FFmpeg/libavcodec/utils.c

/*
 * utils for libavcodec
 * Copyright (c) 2001 Fabrice Bellard
 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * utils.
 */

#include "config.h"
#include "libavutil/attributes.h"
#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/channel_layout.h"
#include "libavutil/crc.h"
#include "libavutil/frame.h"
#include "libavutil/internal.h"
#include "libavutil/mathematics.h"
#include "libavutil/pixdesc.h"
#include "libavutil/imgutils.h"
#include "libavutil/samplefmt.h"
#include "libavutil/dict.h"
#include "avcodec.h"
#include "dsputil.h"
#include "libavutil/opt.h"
#include "thread.h"
#include "internal.h"
#include "bytestream.h"
#include "version.h"
#include <stdlib.h>
#include <stdarg.h>
#include <limits.h>
#include <float.h>

static int volatile entangled_thread_counter = 0;
static int (*lockmgr_cb)(void **mutex, enum AVLockOp op);
static void *codec_mutex;
static void *avformat_mutex;

#if FF_API_FAST_MALLOC && CONFIG_SHARED && HAVE_SYMVER
FF_SYMVER(void*, av_fast_realloc, (void *ptr, unsigned int *size, size_t min_size), "LIBAVCODEC_55")
{
    return av_fast_realloc(ptr, size, min_size);
}

FF_SYMVER(void, av_fast_malloc, (void *ptr, unsigned int *size, size_t min_size), "LIBAVCODEC_55")
{
    av_fast_malloc(ptr, size, min_size);
}
#endif

void av_fast_padded_malloc(void *ptr, unsigned int *size, size_t min_size)
{
    void **p = ptr;
    if (min_size > SIZE_MAX - FF_INPUT_BUFFER_PADDING_SIZE) {
        av_freep(p);
        *size = 0;
        return;
    }
    av_fast_malloc(p, size, min_size + FF_INPUT_BUFFER_PADDING_SIZE);
    if (*size)
        memset((uint8_t *)*p + min_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
}

/* encoder management */
static AVCodec *first_avcodec = NULL;

AVCodec *av_codec_next(const AVCodec *c)
{
    if (c)
        return c->next;
    else
        return first_avcodec;
}

static av_cold void avcodec_init(void)
{
    static int initialized = 0;

    if (initialized != 0)
        return;
    initialized = 1;

    if (CONFIG_DSPUTIL)
        ff_dsputil_static_init();
}

int av_codec_is_encoder(const AVCodec *codec)
{
    return codec && (codec->encode_sub || codec->encode2);
}

int av_codec_is_decoder(const AVCodec *codec)
{
    return codec && codec->decode;
}

av_cold void avcodec_register(AVCodec *codec)
{
    AVCodec **p;
    avcodec_init();
    p = &first_avcodec;
    while (*p != NULL)
        p = &(*p)->next;
    *p          = codec;
    codec->next = NULL;

    if (codec->init_static_data)
        codec->init_static_data(codec);
}

unsigned avcodec_get_edge_width(void)
{
    return EDGE_WIDTH;
}

#if FF_API_SET_DIMENSIONS
void avcodec_set_dimensions(AVCodecContext *s, int width, int height)
{
    ff_set_dimensions(s, width, height);
}
#endif

int ff_set_dimensions(AVCodecContext *s, int width, int height)
{
    int ret = av_image_check_size(width, height, 0, s);

    if (ret < 0)
        width = height = 0;
    s->width  = s->coded_width  = width;
    s->height = s->coded_height = height;

    return ret;
}

int ff_side_data_update_matrix_encoding(AVFrame *frame,
                                        enum AVMatrixEncoding matrix_encoding)
{
    AVFrameSideData *side_data;
    enum AVMatrixEncoding *data;

    side_data = av_frame_get_side_data(frame, AV_FRAME_DATA_MATRIXENCODING);
    if (!side_data)
        side_data = av_frame_new_side_data(frame, AV_FRAME_DATA_MATRIXENCODING,
                                           sizeof(enum AVMatrixEncoding));

    if (!side_data)
        return AVERROR(ENOMEM);

    data  = (enum AVMatrixEncoding*)side_data->data;
    *data = matrix_encoding;

    return 0;
}

#if HAVE_NEON || ARCH_PPC || HAVE_MMX
#   define STRIDE_ALIGN 16
#else
#   define STRIDE_ALIGN 8
#endif

void avcodec_align_dimensions2(AVCodecContext *s, int *width, int *height,
                               int linesize_align[AV_NUM_DATA_POINTERS])
{
    int i;
    int w_align = 1;
    int h_align = 1;

    switch (s->pix_fmt) {
    case AV_PIX_FMT_YUV420P:
    case AV_PIX_FMT_YUYV422:
    case AV_PIX_FMT_UYVY422:
    case AV_PIX_FMT_YUV422P:
    case AV_PIX_FMT_YUV440P:
    case AV_PIX_FMT_YUV444P:
    case AV_PIX_FMT_GBRP:
    case AV_PIX_FMT_GRAY8:
    case AV_PIX_FMT_GRAY16BE:
    case AV_PIX_FMT_GRAY16LE:
    case AV_PIX_FMT_YUVJ420P:
    case AV_PIX_FMT_YUVJ422P:
    case AV_PIX_FMT_YUVJ440P:
    case AV_PIX_FMT_YUVJ444P:
    case AV_PIX_FMT_YUVA420P:
    case AV_PIX_FMT_YUVA422P:
    case AV_PIX_FMT_YUVA444P:
    case AV_PIX_FMT_YUV420P9LE:
    case AV_PIX_FMT_YUV420P9BE:
    case AV_PIX_FMT_YUV420P10LE:
    case AV_PIX_FMT_YUV420P10BE:
    case AV_PIX_FMT_YUV422P9LE:
    case AV_PIX_FMT_YUV422P9BE:
    case AV_PIX_FMT_YUV422P10LE:
    case AV_PIX_FMT_YUV422P10BE:
    case AV_PIX_FMT_YUVA422P10LE:
    case AV_PIX_FMT_YUVA422P10BE:
    case AV_PIX_FMT_YUV444P9LE:
    case AV_PIX_FMT_YUV444P9BE:
    case AV_PIX_FMT_YUV444P10LE:
    case AV_PIX_FMT_YUV444P10BE:
    case AV_PIX_FMT_YUVA444P10LE:
    case AV_PIX_FMT_YUVA444P10BE:
    case AV_PIX_FMT_GBRP9LE:
    case AV_PIX_FMT_GBRP9BE:
    case AV_PIX_FMT_GBRP10LE:
    case AV_PIX_FMT_GBRP10BE:
        w_align = 16; //FIXME assume 16 pixel per macroblock
        h_align = 16 * 2; // interlaced needs 2 macroblocks height
        break;
    case AV_PIX_FMT_YUV411P:
    case AV_PIX_FMT_UYYVYY411:
        w_align = 32;
        h_align = 8;
        break;
    case AV_PIX_FMT_YUV410P:
        if (s->codec_id == AV_CODEC_ID_SVQ1) {
            w_align = 64;
            h_align = 64;
        }
    case AV_PIX_FMT_RGB555:
        if (s->codec_id == AV_CODEC_ID_RPZA) {
            w_align = 4;
            h_align = 4;
        }
    case AV_PIX_FMT_PAL8:
    case AV_PIX_FMT_BGR8:
    case AV_PIX_FMT_RGB8:
        if (s->codec_id == AV_CODEC_ID_SMC) {
            w_align = 4;
            h_align = 4;
        }
        break;
    case AV_PIX_FMT_BGR24:
        if ((s->codec_id == AV_CODEC_ID_MSZH) ||
            (s->codec_id == AV_CODEC_ID_ZLIB)) {
            w_align = 4;
            h_align = 4;
        }
        break;
    default:
        w_align = 1;
        h_align = 1;
        break;
    }

    *width  = FFALIGN(*width, w_align);
    *height = FFALIGN(*height, h_align);
    if (s->codec_id == AV_CODEC_ID_H264)
        // some of the optimized chroma MC reads one line too much
        *height += 2;

    for (i = 0; i < 4; i++)
        linesize_align[i] = STRIDE_ALIGN;
}

void avcodec_align_dimensions(AVCodecContext *s, int *width, int *height)
{
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(s->pix_fmt);
    int chroma_shift = desc->log2_chroma_w;
    int linesize_align[AV_NUM_DATA_POINTERS];
    int align;

    avcodec_align_dimensions2(s, width, height, linesize_align);
    align               = FFMAX(linesize_align[0], linesize_align[3]);
    linesize_align[1] <<= chroma_shift;
    linesize_align[2] <<= chroma_shift;
    align               = FFMAX3(align, linesize_align[1], linesize_align[2]);
    *width              = FFALIGN(*width, align);
}

int avcodec_fill_audio_frame(AVFrame *frame, int nb_channels,
                             enum AVSampleFormat sample_fmt, const uint8_t *buf,
                             int buf_size, int align)
{
    int ch, planar, needed_size, ret = 0;

    needed_size = av_samples_get_buffer_size(NULL, nb_channels,
                                             frame->nb_samples, sample_fmt,
                                             align);
    if (buf_size < needed_size)
        return AVERROR(EINVAL);

    planar = av_sample_fmt_is_planar(sample_fmt);
    if (planar && nb_channels > AV_NUM_DATA_POINTERS) {
        if (!(frame->extended_data = av_mallocz(nb_channels *
                                                sizeof(*frame->extended_data))))
            return AVERROR(ENOMEM);
    } else {
        frame->extended_data = frame->data;
    }

    if ((ret = av_samples_fill_arrays(frame->extended_data, &frame->linesize[0],
                                      buf, nb_channels, frame->nb_samples,
                                      sample_fmt, align)) < 0) {
        if (frame->extended_data != frame->data)
            av_free(frame->extended_data);
        return ret;
    }
    if (frame->extended_data != frame->data) {
        for (ch = 0; ch < AV_NUM_DATA_POINTERS; ch++)
            frame->data[ch] = frame->extended_data[ch];
    }

    return ret;
}

static int update_frame_pool(AVCodecContext *avctx, AVFrame *frame)
{
    FramePool *pool = avctx->internal->pool;
    int i, ret;

    switch (avctx->codec_type) {
    case AVMEDIA_TYPE_VIDEO: {
        AVPicture picture;
        int size[4] = { 0 };
        int w = frame->width;
        int h = frame->height;
        int tmpsize, unaligned;

        if (pool->format == frame->format &&
            pool->width == frame->width && pool->height == frame->height)
            return 0;

        avcodec_align_dimensions2(avctx, &w, &h, pool->stride_align);

        if (!(avctx->flags & CODEC_FLAG_EMU_EDGE)) {
            w += EDGE_WIDTH * 2;
            h += EDGE_WIDTH * 2;
        }

        do {
            // NOTE: do not align linesizes individually, this breaks e.g. assumptions
            // that linesize[0] == 2*linesize[1] in the MPEG-encoder for 4:2:2
            av_image_fill_linesizes(picture.linesize, avctx->pix_fmt, w);
            // increase alignment of w for next try (rhs gives the lowest bit set in w)
            w += w & ~(w - 1);

            unaligned = 0;
            for (i = 0; i < 4; i++)
                unaligned |= picture.linesize[i] % pool->stride_align[i];
        } while (unaligned);

        tmpsize = av_image_fill_pointers(picture.data, avctx->pix_fmt, h,
                                         NULL, picture.linesize);
        if (tmpsize < 0)
            return -1;

        for (i = 0; i < 3 && picture.data[i + 1]; i++)
            size[i] = picture.data[i + 1] - picture.data[i];
        size[i] = tmpsize - (picture.data[i] - picture.data[0]);

        for (i = 0; i < 4; i++) {
            av_buffer_pool_uninit(&pool->pools[i]);
            pool->linesize[i] = picture.linesize[i];
            if (size[i]) {
                pool->pools[i] = av_buffer_pool_init(size[i] + 16, NULL);
                if (!pool->pools[i]) {
                    ret = AVERROR(ENOMEM);
                    goto fail;
                }
            }
        }
        pool->format = frame->format;
        pool->width  = frame->width;
        pool->height = frame->height;

        break;
        }
    case AVMEDIA_TYPE_AUDIO: {
        int ch     = av_get_channel_layout_nb_channels(frame->channel_layout);
        int planar = av_sample_fmt_is_planar(frame->format);
        int planes = planar ? ch : 1;

        if (pool->format == frame->format && pool->planes == planes &&
            pool->channels == ch && frame->nb_samples == pool->samples)
            return 0;

        av_buffer_pool_uninit(&pool->pools[0]);
        ret = av_samples_get_buffer_size(&pool->linesize[0], ch,
                                         frame->nb_samples, frame->format, 0);
        if (ret < 0)
            goto fail;

        pool->pools[0] = av_buffer_pool_init(pool->linesize[0], NULL);
        if (!pool->pools[0]) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }

        pool->format     = frame->format;
        pool->planes     = planes;
        pool->channels   = ch;
        pool->samples = frame->nb_samples;
        break;
        }
    default: av_assert0(0);
    }
    return 0;
fail:
    for (i = 0; i < 4; i++)
        av_buffer_pool_uninit(&pool->pools[i]);
    pool->format = -1;
    pool->planes = pool->channels = pool->samples = 0;
    pool->width  = pool->height = 0;
    return ret;
}

static int audio_get_buffer(AVCodecContext *avctx, AVFrame *frame)
{
    FramePool *pool = avctx->internal->pool;
    int planes = pool->planes;
    int i;

    frame->linesize[0] = pool->linesize[0];

    if (planes > AV_NUM_DATA_POINTERS) {
        frame->extended_data = av_mallocz(planes * sizeof(*frame->extended_data));
        frame->nb_extended_buf = planes - AV_NUM_DATA_POINTERS;
        frame->extended_buf  = av_mallocz(frame->nb_extended_buf *
                                          sizeof(*frame->extended_buf));
        if (!frame->extended_data || !frame->extended_buf) {
            av_freep(&frame->extended_data);
            av_freep(&frame->extended_buf);
            return AVERROR(ENOMEM);
        }
    } else
        frame->extended_data = frame->data;

    for (i = 0; i < FFMIN(planes, AV_NUM_DATA_POINTERS); i++) {
        frame->buf[i] = av_buffer_pool_get(pool->pools[0]);
        if (!frame->buf[i])
            goto fail;
        frame->extended_data[i] = frame->data[i] = frame->buf[i]->data;
    }
    for (i = 0; i < frame->nb_extended_buf; i++) {
        frame->extended_buf[i] = av_buffer_pool_get(pool->pools[0]);
        if (!frame->extended_buf[i])
            goto fail;
        frame->extended_data[i + AV_NUM_DATA_POINTERS] = frame->extended_buf[i]->data;
    }

    if (avctx->debug & FF_DEBUG_BUFFERS)
        av_log(avctx, AV_LOG_DEBUG, "default_get_buffer called on frame %p", frame);

    return 0;
fail:
    av_frame_unref(frame);
    return AVERROR(ENOMEM);
}

static int video_get_buffer(AVCodecContext *s, AVFrame *pic)
{
    FramePool *pool = s->internal->pool;
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pic->format);
    int pixel_size = desc->comp[0].step_minus1 + 1;
    int h_chroma_shift, v_chroma_shift;
    int i;

    if (pic->data[0] != NULL) {
        av_log(s, AV_LOG_ERROR, "pic->data[0]!=NULL in avcodec_default_get_buffer\n");
        return -1;
    }

    memset(pic->data, 0, sizeof(pic->data));
    pic->extended_data = pic->data;

    av_pix_fmt_get_chroma_sub_sample(s->pix_fmt, &h_chroma_shift, &v_chroma_shift);

    for (i = 0; i < 4 && pool->pools[i]; i++) {
        const int h_shift = i == 0 ? 0 : h_chroma_shift;
        const int v_shift = i == 0 ? 0 : v_chroma_shift;

        pic->linesize[i] = pool->linesize[i];

        pic->buf[i] = av_buffer_pool_get(pool->pools[i]);
        if (!pic->buf[i])
            goto fail;

        // no edge if EDGE EMU or not planar YUV
        if ((s->flags & CODEC_FLAG_EMU_EDGE) || !pool->pools[2])
            pic->data[i] = pic->buf[i]->data;
        else {
            pic->data[i] = pic->buf[i]->data +
                FFALIGN((pic->linesize[i] * EDGE_WIDTH >> v_shift) +
                        (pixel_size * EDGE_WIDTH >> h_shift), pool->stride_align[i]);
        }
    }
    for (; i < AV_NUM_DATA_POINTERS; i++) {
        pic->data[i] = NULL;
        pic->linesize[i] = 0;
    }
    if (pic->data[1] && !pic->data[2])
        avpriv_set_systematic_pal2((uint32_t *)pic->data[1], s->pix_fmt);

    if (s->debug & FF_DEBUG_BUFFERS)
        av_log(s, AV_LOG_DEBUG, "default_get_buffer called on pic %p\n", pic);

    return 0;
fail:
    av_frame_unref(pic);
    return AVERROR(ENOMEM);
}

int avcodec_default_get_buffer2(AVCodecContext *avctx, AVFrame *frame, int flags)
{
    int ret;

    if ((ret = update_frame_pool(avctx, frame)) < 0)
        return ret;

#if FF_API_GET_BUFFER
FF_DISABLE_DEPRECATION_WARNINGS
    frame->type = FF_BUFFER_TYPE_INTERNAL;
FF_ENABLE_DEPRECATION_WARNINGS
#endif

    switch (avctx->codec_type) {
    case AVMEDIA_TYPE_VIDEO:
        return video_get_buffer(avctx, frame);
    case AVMEDIA_TYPE_AUDIO:
        return audio_get_buffer(avctx, frame);
    default:
        return -1;
    }
}

#if FF_API_GET_BUFFER
FF_DISABLE_DEPRECATION_WARNINGS
int avcodec_default_get_buffer(AVCodecContext *avctx, AVFrame *frame)
{
    return avcodec_default_get_buffer2(avctx, frame, 0);
}

typedef struct CompatReleaseBufPriv {
    AVCodecContext avctx;
    AVFrame frame;
} CompatReleaseBufPriv;

static void compat_free_buffer(void *opaque, uint8_t *data)
{
    CompatReleaseBufPriv *priv = opaque;
    if (priv->avctx.release_buffer)
        priv->avctx.release_buffer(&priv->avctx, &priv->frame);
    av_freep(&priv);
}

static void compat_release_buffer(void *opaque, uint8_t *data)
{
    AVBufferRef *buf = opaque;
    av_buffer_unref(&buf);
}
FF_ENABLE_DEPRECATION_WARNINGS
#endif

int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
{
    int ret;

    switch (avctx->codec_type) {
    case AVMEDIA_TYPE_VIDEO:
        frame->width  = FFMAX(avctx->width, avctx->coded_width);
        frame->height = FFMAX(avctx->height, avctx->coded_height);
        if (frame->format < 0)
            frame->format              = avctx->pix_fmt;
        if (!frame->sample_aspect_ratio.num)
            frame->sample_aspect_ratio = avctx->sample_aspect_ratio;

        if ((ret = av_image_check_size(avctx->width, avctx->height, 0, avctx)) < 0)
            return ret;
        break;
    case AVMEDIA_TYPE_AUDIO:
        if (!frame->sample_rate)
            frame->sample_rate    = avctx->sample_rate;
        if (frame->format < 0)
            frame->format         = avctx->sample_fmt;
        if (!frame->channel_layout) {
            if (avctx->channel_layout) {
                 if (av_get_channel_layout_nb_channels(avctx->channel_layout) !=
                     avctx->channels) {
                     av_log(avctx, AV_LOG_ERROR, "Inconsistent channel "
                            "configuration.\n");
                     return AVERROR(EINVAL);
                 }

                frame->channel_layout = avctx->channel_layout;
            } else {
                if (avctx->channels > FF_SANE_NB_CHANNELS) {
                    av_log(avctx, AV_LOG_ERROR, "Too many channels: %d.\n",
                           avctx->channels);
                    return AVERROR(ENOSYS);
                }

                frame->channel_layout = av_get_default_channel_layout(avctx->channels);
                if (!frame->channel_layout)
                    frame->channel_layout = (1ULL << avctx->channels) - 1;
            }
        }
        break;
    default: return AVERROR(EINVAL);
    }

    frame->pkt_pts = avctx->internal->pkt ? avctx->internal->pkt->pts : AV_NOPTS_VALUE;
    frame->reordered_opaque = avctx->reordered_opaque;

#if FF_API_GET_BUFFER
FF_DISABLE_DEPRECATION_WARNINGS
    /*
     * Wrap an old get_buffer()-allocated buffer in an bunch of AVBuffers.
     * We wrap each plane in its own AVBuffer. Each of those has a reference to
     * a dummy AVBuffer as its private data, unreffing it on free.
     * When all the planes are freed, the dummy buffer's free callback calls
     * release_buffer().
     */
    if (avctx->get_buffer) {
        CompatReleaseBufPriv *priv = NULL;
        AVBufferRef *dummy_buf = NULL;
        int planes, i, ret;

        if (flags & AV_GET_BUFFER_FLAG_REF)
            frame->reference    = 1;

        ret = avctx->get_buffer(avctx, frame);
        if (ret < 0)
            return ret;

        /* return if the buffers are already set up
         * this would happen e.g. when a custom get_buffer() calls
         * avcodec_default_get_buffer
         */
        if (frame->buf[0])
            return 0;

        priv = av_mallocz(sizeof(*priv));
        if (!priv) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }
        priv->avctx = *avctx;
        priv->frame = *frame;

        dummy_buf = av_buffer_create(NULL, 0, compat_free_buffer, priv, 0);
        if (!dummy_buf) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }

#define WRAP_PLANE(ref_out, data, data_size)                            \
do {                                                                    \
    AVBufferRef *dummy_ref = av_buffer_ref(dummy_buf);                  \
    if (!dummy_ref) {                                                   \
        ret = AVERROR(ENOMEM);                                          \
        goto fail;                                                      \
    }                                                                   \
    ref_out = av_buffer_create(data, data_size, compat_release_buffer,  \
                               dummy_ref, 0);                           \
    if (!ref_out) {                                                     \
        av_frame_unref(frame);                                          \
        ret = AVERROR(ENOMEM);                                          \
        goto fail;                                                      \
    }                                                                   \
} while (0)

        if (avctx->codec_type == AVMEDIA_TYPE_VIDEO) {
            const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(frame->format);

            planes = av_pix_fmt_count_planes(frame->format);
            /* workaround for AVHWAccel plane count of 0, buf[0] is used as
               check for allocated buffers: make libavcodec happy */
            if (desc && desc->flags & AV_PIX_FMT_FLAG_HWACCEL)
                planes = 1;
            if (!desc || planes <= 0) {
                ret = AVERROR(EINVAL);
                goto fail;
            }

            for (i = 0; i < planes; i++) {
                int v_shift    = (i == 1 || i == 2) ? desc->log2_chroma_h : 0;
                int plane_size = (frame->height >> v_shift) * frame->linesize[i];

                WRAP_PLANE(frame->buf[i], frame->data[i], plane_size);
            }
        } else {
            int planar = av_sample_fmt_is_planar(frame->format);
            planes = planar ? avctx->channels : 1;

            if (planes > FF_ARRAY_ELEMS(frame->buf)) {
                frame->nb_extended_buf = planes - FF_ARRAY_ELEMS(frame->buf);
                frame->extended_buf = av_malloc(sizeof(*frame->extended_buf) *
                                                frame->nb_extended_buf);
                if (!frame->extended_buf) {
                    ret = AVERROR(ENOMEM);
                    goto fail;
                }
            }

            for (i = 0; i < FFMIN(planes, FF_ARRAY_ELEMS(frame->buf)); i++)
                WRAP_PLANE(frame->buf[i], frame->extended_data[i], frame->linesize[0]);

            for (i = 0; i < frame->nb_extended_buf; i++)
                WRAP_PLANE(frame->extended_buf[i],
                           frame->extended_data[i + FF_ARRAY_ELEMS(frame->buf)],
                           frame->linesize[0]);
        }

        av_buffer_unref(&dummy_buf);

        frame->width  = avctx->width;
        frame->height = avctx->height;

        return 0;

fail:
        avctx->release_buffer(avctx, frame);
        av_freep(&priv);
        av_buffer_unref(&dummy_buf);
        return ret;
    }
FF_ENABLE_DEPRECATION_WARNINGS
#endif

    ret = avctx->get_buffer2(avctx, frame, flags);

    if (avctx->codec_type == AVMEDIA_TYPE_VIDEO) {
        frame->width  = avctx->width;
        frame->height = avctx->height;
    }

    return ret;
}

int ff_reget_buffer(AVCodecContext *avctx, AVFrame *frame)
{
    AVFrame tmp;
    int ret;

    av_assert0(avctx->codec_type == AVMEDIA_TYPE_VIDEO);

    if (!frame->data[0])
        return ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF);

    if (av_frame_is_writable(frame))
        return 0;

    av_frame_move_ref(&tmp, frame);

    ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF);
    if (ret < 0) {
        av_frame_unref(&tmp);
        return ret;
    }

    av_image_copy(frame->data, frame->linesize, tmp.data, tmp.linesize,
                  frame->format, frame->width, frame->height);

    av_frame_unref(&tmp);

    return 0;
}

#if FF_API_GET_BUFFER
void avcodec_default_release_buffer(AVCodecContext *s, AVFrame *pic)
{
    av_frame_unref(pic);
}

int avcodec_default_reget_buffer(AVCodecContext *s, AVFrame *pic)
{
    av_assert0(0);
    return AVERROR_BUG;
}
#endif

int avcodec_default_execute(AVCodecContext *c, int (*func)(AVCodecContext *c2, void *arg2), void *arg, int *ret, int count, int size)
{
    int i;

    for (i = 0; i < count; i++) {
        int r = func(c, (char *)arg + i * size);
        if (ret)
            ret[i] = r;
    }
    return 0;
}

int avcodec_default_execute2(AVCodecContext *c, int (*func)(AVCodecContext *c2, void *arg2, int jobnr, int threadnr), void *arg, int *ret, int count)
{
    int i;

    for (i = 0; i < count; i++) {
        int r = func(c, arg, i, 0);
        if (ret)
            ret[i] = r;
    }
    return 0;
}

static int is_hwaccel_pix_fmt(enum AVPixelFormat pix_fmt)
{
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pix_fmt);
    return desc->flags & AV_PIX_FMT_FLAG_HWACCEL;
}

enum AVPixelFormat avcodec_default_get_format(struct AVCodecContext *s, const enum AVPixelFormat *fmt)
{
    while (*fmt != AV_PIX_FMT_NONE && is_hwaccel_pix_fmt(*fmt))
        ++fmt;
    return fmt[0];
}

#if FF_API_AVFRAME_LAVC
void avcodec_get_frame_defaults(AVFrame *frame)
{
    if (frame->extended_data != frame->data)
        av_freep(&frame->extended_data);

    memset(frame, 0, sizeof(AVFrame));

    frame->pts                 = AV_NOPTS_VALUE;
    frame->key_frame           = 1;
    frame->sample_aspect_ratio = (AVRational) {0, 1 };
    frame->format              = -1; /* unknown */
    frame->extended_data       = frame->data;
}

AVFrame *avcodec_alloc_frame(void)
{
    AVFrame *frame = av_mallocz(sizeof(AVFrame));

    if (frame == NULL)
        return NULL;

    avcodec_get_frame_defaults(frame);

    return frame;
}

void avcodec_free_frame(AVFrame **frame)
{
    av_frame_free(frame);
}
#endif

int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options)
{
    int ret = 0;
    AVDictionary *tmp = NULL;

    if (avcodec_is_open(avctx))
        return 0;

    if ((!codec && !avctx->codec)) {
        av_log(avctx, AV_LOG_ERROR, "No codec provided to avcodec_open2().\n");
        return AVERROR(EINVAL);
    }
    if ((codec && avctx->codec && codec != avctx->codec)) {
        av_log(avctx, AV_LOG_ERROR, "This AVCodecContext was allocated for %s, "
                                    "but %s passed to avcodec_open2().\n", avctx->codec->name, codec->name);
        return AVERROR(EINVAL);
    }
    if (!codec)
        codec = avctx->codec;

    if (avctx->extradata_size < 0 || avctx->extradata_size >= FF_MAX_EXTRADATA_SIZE)
        return AVERROR(EINVAL);

    if (options)
        av_dict_copy(&tmp, *options, 0);

    /* If there is a user-supplied mutex locking routine, call it. */
    if (lockmgr_cb) {
        if ((*lockmgr_cb)(&codec_mutex, AV_LOCK_OBTAIN))
            return -1;
    }

    entangled_thread_counter++;
    if (entangled_thread_counter != 1) {
        av_log(avctx, AV_LOG_ERROR, "insufficient thread locking around avcodec_open/close()\n");
        ret = -1;
        goto end;
    }

    avctx->internal = av_mallocz(sizeof(AVCodecInternal));
    if (!avctx->internal) {
        ret = AVERROR(ENOMEM);
        goto end;
    }

    avctx->internal->pool = av_mallocz(sizeof(*avctx->internal->pool));
    if (!avctx->internal->pool) {
        ret = AVERROR(ENOMEM);
        goto free_and_end;
    }

    avctx->internal->to_free = av_frame_alloc();
    if (!avctx->internal->to_free) {
        ret = AVERROR(ENOMEM);
        goto free_and_end;
    }

    if (codec->priv_data_size > 0) {
        if (!avctx->priv_data) {
            avctx->priv_data = av_mallocz(codec->priv_data_size);
            if (!avctx->priv_data) {
                ret = AVERROR(ENOMEM);
                goto end;
            }
            if (codec->priv_class) {
                *(const AVClass **)avctx->priv_data = codec->priv_class;
                av_opt_set_defaults(avctx->priv_data);
            }
        }
        if (codec->priv_class && (ret = av_opt_set_dict(avctx->priv_data, &tmp)) < 0)
            goto free_and_end;
    } else {
        avctx->priv_data = NULL;
    }
    if ((ret = av_opt_set_dict(avctx, &tmp)) < 0)
        goto free_and_end;

    if (avctx->coded_width && avctx->coded_height && !avctx->width && !avctx->height)
        ret = ff_set_dimensions(avctx, avctx->coded_width, avctx->coded_height);
    else if (avctx->width && avctx->height)
        ret = ff_set_dimensions(avctx, avctx->width, avctx->height);
    if (ret < 0)
        goto free_and_end;

    if ((avctx->coded_width || avctx->coded_height || avctx->width || avctx->height)
        && (  av_image_check_size(avctx->coded_width, avctx->coded_height, 0, avctx) < 0
           || av_image_check_size(avctx->width,       avctx->height,       0, avctx) < 0)) {
        av_log(avctx, AV_LOG_WARNING, "ignoring invalid width/height values\n");
        ff_set_dimensions(avctx, 0, 0);
    }

    /* if the decoder init function was already called previously,
     * free the already allocated subtitle_header before overwriting it */
    if (av_codec_is_decoder(codec))
        av_freep(&avctx->subtitle_header);

    if (avctx->channels > FF_SANE_NB_CHANNELS) {
        ret = AVERROR(EINVAL);
        goto free_and_end;
    }

    avctx->codec = codec;
    if ((avctx->codec_type == AVMEDIA_TYPE_UNKNOWN || avctx->codec_type == codec->type) &&
        avctx->codec_id == AV_CODEC_ID_NONE) {
        avctx->codec_type = codec->type;
        avctx->codec_id   = codec->id;
    }
    if (avctx->codec_id != codec->id || (avctx->codec_type != codec->type
                                         && avctx->codec_type != AVMEDIA_TYPE_ATTACHMENT)) {
        av_log(avctx, AV_LOG_ERROR, "codec type or id mismatches\n");
        ret = AVERROR(EINVAL);
        goto free_and_end;
    }
    avctx->frame_number = 0;

    if (avctx->codec->capabilities & CODEC_CAP_EXPERIMENTAL &&
        avctx->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL) {
        ret = AVERROR_EXPERIMENTAL;
        goto free_and_end;
    }

    if (avctx->codec_type == AVMEDIA_TYPE_AUDIO &&
        (!avctx->time_base.num || !avctx->time_base.den)) {
        avctx->time_base.num = 1;
        avctx->time_base.den = avctx->sample_rate;
    }

    if (HAVE_THREADS) {
        ret = ff_thread_init(avctx);
        if (ret < 0) {
            goto free_and_end;
        }
    }
    if (!HAVE_THREADS && !(codec->capabilities & CODEC_CAP_AUTO_THREADS))
        avctx->thread_count = 1;

    if (av_codec_is_encoder(avctx->codec)) {
        int i;
        if (avctx->codec->sample_fmts) {
            for (i = 0; avctx->codec->sample_fmts[i] != AV_SAMPLE_FMT_NONE; i++) {
                if (avctx->sample_fmt == avctx->codec->sample_fmts[i])
                    break;
                if (avctx->channels == 1 &&
                    av_get_planar_sample_fmt(avctx->sample_fmt) ==
                    av_get_planar_sample_fmt(avctx->codec->sample_fmts[i])) {
                    avctx->sample_fmt = avctx->codec->sample_fmts[i];
                    break;
                }
            }
            if (avctx->codec->sample_fmts[i] == AV_SAMPLE_FMT_NONE) {
                av_log(avctx, AV_LOG_ERROR, "Specified sample_fmt is not supported.\n");
                ret = AVERROR(EINVAL);
                goto free_and_end;
            }
        }
        if (avctx->codec->pix_fmts) {
            for (i = 0; avctx->codec->pix_fmts[i] != AV_PIX_FMT_NONE; i++)
                if (avctx->pix_fmt == avctx->codec->pix_fmts[i])
                    break;
            if (avctx->codec->pix_fmts[i] == AV_PIX_FMT_NONE) {
                av_log(avctx, AV_LOG_ERROR, "Specified pix_fmt is not supported\n");
                ret = AVERROR(EINVAL);
                goto free_and_end;
            }
        }
        if (avctx->codec->supported_samplerates) {
            for (i = 0; avctx->codec->supported_samplerates[i] != 0; i++)
                if (avctx->sample_rate == avctx->codec->supported_samplerates[i])
                    break;
            if (avctx->codec->supported_samplerates[i] == 0) {
                av_log(avctx, AV_LOG_ERROR, "Specified sample_rate is not supported\n");
                ret = AVERROR(EINVAL);
                goto free_and_end;
            }
        }
        if (avctx->codec->channel_layouts) {
            if (!avctx->channel_layout) {
                av_log(avctx, AV_LOG_WARNING, "channel_layout not specified\n");
            } else {
                for (i = 0; avctx->codec->channel_layouts[i] != 0; i++)
                    if (avctx->channel_layout == avctx->codec->channel_layouts[i])
                        break;
                if (avctx->codec->channel_layouts[i] == 0) {
                    av_log(avctx, AV_LOG_ERROR, "Specified channel_layout is not supported\n");
                    ret = AVERROR(EINVAL);
                    goto free_and_end;
                }
            }
        }
        if (avctx->channel_layout && avctx->channels) {
            if (av_get_channel_layout_nb_channels(avctx->channel_layout) != avctx->channels) {
                av_log(avctx, AV_LOG_ERROR, "channel layout does not match number of channels\n");
                ret = AVERROR(EINVAL);
                goto free_and_end;
            }
        } else if (avctx->channel_layout) {
            avctx->channels = av_get_channel_layout_nb_channels(avctx->channel_layout);
        }

        if (!avctx->rc_initial_buffer_occupancy)
            avctx->rc_initial_buffer_occupancy = avctx->rc_buffer_size * 3 / 4;
    }

    if (avctx->codec->init && !(avctx->active_thread_type & FF_THREAD_FRAME)) {
        ret = avctx->codec->init(avctx);
        if (ret < 0) {
            goto free_and_end;
        }
    }

    if (av_codec_is_decoder(avctx->codec)) {
        /* validate channel layout from the decoder */
        if (avctx->channel_layout) {
            int channels = av_get_channel_layout_nb_channels(avctx->channel_layout);
            if (!avctx->channels)
                avctx->channels = channels;
            else if (channels != avctx->channels) {
                av_log(avctx, AV_LOG_WARNING,
                       "channel layout does not match number of channels\n");
                avctx->channel_layout = 0;
            }
        }
        if (avctx->channels && avctx->channels < 0 ||
            avctx->channels > FF_SANE_NB_CHANNELS) {
            ret = AVERROR(EINVAL);
            goto free_and_end;
        }
    }
end:
    entangled_thread_counter--;

    /* Release any user-supplied mutex. */
    if (lockmgr_cb) {
        (*lockmgr_cb)(&codec_mutex, AV_LOCK_RELEASE);
    }
    if (options) {
        av_dict_free(options);
        *options = tmp;
    }

    return ret;
free_and_end:
    av_dict_free(&tmp);
    av_freep(&avctx->priv_data);
    if (avctx->internal) {
        av_frame_free(&avctx->internal->to_free);
        av_freep(&avctx->internal->pool);
    }
    av_freep(&avctx->internal);
    avctx->codec = NULL;
    goto end;
}

int ff_alloc_packet(AVPacket *avpkt, int size)
{
    if (size > INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE)
        return AVERROR(EINVAL);

    if (avpkt->data) {
        AVBufferRef *buf = avpkt->buf;
#if FF_API_DESTRUCT_PACKET
FF_DISABLE_DEPRECATION_WARNINGS
        void *destruct = avpkt->destruct;
FF_ENABLE_DEPRECATION_WARNINGS
#endif

        if (avpkt->size < size)
            return AVERROR(EINVAL);

        av_init_packet(avpkt);
#if FF_API_DESTRUCT_PACKET
FF_DISABLE_DEPRECATION_WARNINGS
        avpkt->destruct = destruct;
FF_ENABLE_DEPRECATION_WARNINGS
#endif
        avpkt->buf      = buf;
        avpkt->size     = size;
        return 0;
    } else {
        return av_new_packet(avpkt, size);
    }
}

/**
 * Pad last frame with silence.
 */
static int pad_last_frame(AVCodecContext *s, AVFrame **dst, const AVFrame *src)
{
    AVFrame *frame = NULL;
    int ret;

    if (!(frame = av_frame_alloc()))
        return AVERROR(ENOMEM);

    frame->format         = src->format;
    frame->channel_layout = src->channel_layout;
    frame->nb_samples     = s->frame_size;
    ret = av_frame_get_buffer(frame, 32);
    if (ret < 0)
        goto fail;

    ret = av_frame_copy_props(frame, src);
    if (ret < 0)
        goto fail;

    if ((ret = av_samples_copy(frame->extended_data, src->extended_data, 0, 0,
                               src->nb_samples, s->channels, s->sample_fmt)) < 0)
        goto fail;
    if ((ret = av_samples_set_silence(frame->extended_data, src->nb_samples,
                                      frame->nb_samples - src->nb_samples,
                                      s->channels, s->sample_fmt)) < 0)
        goto fail;

    *dst = frame;

    return 0;

fail:
    av_frame_free(&frame);
    return ret;
}

int attribute_align_arg avcodec_encode_audio2(AVCodecContext *avctx,
                                              AVPacket *avpkt,
                                              const AVFrame *frame,
                                              int *got_packet_ptr)
{
    AVFrame tmp;
    AVFrame *padded_frame = NULL;
    int ret;
    int user_packet = !!avpkt->data;

    *got_packet_ptr = 0;

    if (!(avctx->codec->capabilities & CODEC_CAP_DELAY) && !frame) {
        av_free_packet(avpkt);
        av_init_packet(avpkt);
        return 0;
    }

    /* ensure that extended_data is properly set */
    if (frame && !frame->extended_data) {
        if (av_sample_fmt_is_planar(avctx->sample_fmt) &&
            avctx->channels > AV_NUM_DATA_POINTERS) {
            av_log(avctx, AV_LOG_ERROR, "Encoding to a planar sample format, "
                                        "with more than %d channels, but extended_data is not set.\n",
                   AV_NUM_DATA_POINTERS);
            return AVERROR(EINVAL);
        }
        av_log(avctx, AV_LOG_WARNING, "extended_data is not set.\n");

        tmp = *frame;
        tmp.extended_data = tmp.data;
        frame = &tmp;
    }

    /* check for valid frame size */
    if (frame) {
        if (avctx->codec->capabilities & CODEC_CAP_SMALL_LAST_FRAME) {
            if (frame->nb_samples > avctx->frame_size)
                return AVERROR(EINVAL);
        } else if (!(avctx->codec->capabilities & CODEC_CAP_VARIABLE_FRAME_SIZE)) {
            if (frame->nb_samples < avctx->frame_size &&
                !avctx->internal->last_audio_frame) {
                ret = pad_last_frame(avctx, &padded_frame, frame);
                if (ret < 0)
                    return ret;

                frame = padded_frame;
                avctx->internal->last_audio_frame = 1;
            }

            if (frame->nb_samples != avctx->frame_size) {
                ret = AVERROR(EINVAL);
                goto end;
            }
        }
    }

    ret = avctx->codec->encode2(avctx, avpkt, frame, got_packet_ptr);
    if (!ret) {
        if (*got_packet_ptr) {
            if (!(avctx->codec->capabilities & CODEC_CAP_DELAY)) {
                if (avpkt->pts == AV_NOPTS_VALUE)
                    avpkt->pts = frame->pts;
                if (!avpkt->duration)
                    avpkt->duration = ff_samples_to_time_base(avctx,
                                                              frame->nb_samples);
            }
            avpkt->dts = avpkt->pts;
        } else {
            avpkt->size = 0;
        }

        if (!user_packet && avpkt->size) {
            ret = av_buffer_realloc(&avpkt->buf, avpkt->size);
            if (ret >= 0)
                avpkt->data = avpkt->buf->data;
        }

        avctx->frame_number++;
    }

    if (ret < 0 || !*got_packet_ptr) {
        av_free_packet(avpkt);
        av_init_packet(avpkt);
        goto end;
    }

    /* NOTE: if we add any audio encoders which output non-keyframe packets,
     *       this needs to be moved to the encoders, but for now we can do it
     *       here to simplify things */
    avpkt->flags |= AV_PKT_FLAG_KEY;

end:
    av_frame_free(&padded_frame);

    return ret;
}

int attribute_align_arg avcodec_encode_video2(AVCodecContext *avctx,
                                              AVPacket *avpkt,
                                              const AVFrame *frame,
                                              int *got_packet_ptr)
{
    int ret;
    int user_packet = !!avpkt->data;

    *got_packet_ptr = 0;

    if (!(avctx->codec->capabilities & CODEC_CAP_DELAY) && !frame) {
        av_free_packet(avpkt);
        av_init_packet(avpkt);
        avpkt->size = 0;
        return 0;
    }

    if (av_image_check_size(avctx->width, avctx->height, 0, avctx))
        return AVERROR(EINVAL);

    av_assert0(avctx->codec->encode2);

    ret = avctx->codec->encode2(avctx, avpkt, frame, got_packet_ptr);
    if (!ret) {
        if (!*got_packet_ptr)
            avpkt->size = 0;
        else if (!(avctx->codec->capabilities & CODEC_CAP_DELAY))
            avpkt->pts = avpkt->dts = frame->pts;

        if (!user_packet && avpkt->size) {
            ret = av_buffer_realloc(&avpkt->buf, avpkt->size);
            if (ret >= 0)
                avpkt->data = avpkt->buf->data;
        }

        avctx->frame_number++;
    }

    if (ret < 0 || !*got_packet_ptr)
        av_free_packet(avpkt);

    emms_c();
    return ret;
}

int avcodec_encode_subtitle(AVCodecContext *avctx, uint8_t *buf, int buf_size,
                            const AVSubtitle *sub)
{
    int ret;
    if (sub->start_display_time) {
        av_log(avctx, AV_LOG_ERROR, "start_display_time must be 0.\n");
        return -1;
    }
    if (sub->num_rects == 0 || !sub->rects)
        return -1;
    ret = avctx->codec->encode_sub(avctx, buf, buf_size, sub);
    avctx->frame_number++;
    return ret;
}

static int apply_param_change(AVCodecContext *avctx, AVPacket *avpkt)
{
    int size = 0, ret;
    const uint8_t *data;
    uint32_t flags;

    data = av_packet_get_side_data(avpkt, AV_PKT_DATA_PARAM_CHANGE, &size);
    if (!data)
        return 0;

    if (!(avctx->codec->capabilities & CODEC_CAP_PARAM_CHANGE)) {
        av_log(avctx, AV_LOG_ERROR, "This decoder does not support parameter "
               "changes, but PARAM_CHANGE side data was sent to it.\n");
        return AVERROR(EINVAL);
    }

    if (size < 4)
        goto fail;

    flags = bytestream_get_le32(&data);
    size -= 4;

    if (flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT) {
        if (size < 4)
            goto fail;
        avctx->channels = bytestream_get_le32(&data);
        size -= 4;
    }
    if (flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT) {
        if (size < 8)
            goto fail;
        avctx->channel_layout = bytestream_get_le64(&data);
        size -= 8;
    }
    if (flags & AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE) {
        if (size < 4)
            goto fail;
        avctx->sample_rate = bytestream_get_le32(&data);
        size -= 4;
    }
    if (flags & AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS) {
        if (size < 8)
            goto fail;
        avctx->width  = bytestream_get_le32(&data);
        avctx->height = bytestream_get_le32(&data);
        size -= 8;
        ret = ff_set_dimensions(avctx, avctx->width, avctx->height);
        if (ret < 0)
            return ret;
    }

    return 0;
fail:
    av_log(avctx, AV_LOG_ERROR, "PARAM_CHANGE side data too small.\n");
    return AVERROR_INVALIDDATA;
}

static int unrefcount_frame(AVCodecInternal *avci, AVFrame *frame)
{
    int ret;

    /* move the original frame to our backup */
    av_frame_unref(avci->to_free);
    av_frame_move_ref(avci->to_free, frame);

    /* now copy everything except the AVBufferRefs back
     * note that we make a COPY of the side data, so calling av_frame_free() on
     * the caller's frame will work properly */
    ret = av_frame_copy_props(frame, avci->to_free);
    if (ret < 0)
        return ret;

    memcpy(frame->data,     avci->to_free->data,     sizeof(frame->data));
    memcpy(frame->linesize, avci->to_free->linesize, sizeof(frame->linesize));
    if (avci->to_free->extended_data != avci->to_free->data) {
        int planes = av_get_channel_layout_nb_channels(avci->to_free->channel_layout);
        int size   = planes * sizeof(*frame->extended_data);

        if (!size) {
            av_frame_unref(frame);
            return AVERROR_BUG;
        }

        frame->extended_data = av_malloc(size);
        if (!frame->extended_data) {
            av_frame_unref(frame);
            return AVERROR(ENOMEM);
        }
        memcpy(frame->extended_data, avci->to_free->extended_data,
               size);
    } else
        frame->extended_data = frame->data;

    frame->format         = avci->to_free->format;
    frame->width          = avci->to_free->width;
    frame->height         = avci->to_free->height;
    frame->channel_layout = avci->to_free->channel_layout;
    frame->nb_samples     = avci->to_free->nb_samples;

    return 0;
}

int attribute_align_arg avcodec_decode_video2(AVCodecContext *avctx, AVFrame *picture,
                                              int *got_picture_ptr,
                                              AVPacket *avpkt)
{
    AVCodecInternal *avci = avctx->internal;
    int ret;

    *got_picture_ptr = 0;
    if ((avctx->coded_width || avctx->coded_height) && av_image_check_size(avctx->coded_width, avctx->coded_height, 0, avctx))
        return -1;

    avctx->internal->pkt = avpkt;
    ret = apply_param_change(avctx, avpkt);
    if (ret < 0) {
        av_log(avctx, AV_LOG_ERROR, "Error applying parameter changes.\n");
        if (avctx->err_recognition & AV_EF_EXPLODE)
            return ret;
    }

    av_frame_unref(picture);

    if ((avctx->codec->capabilities & CODEC_CAP_DELAY) || avpkt->size || (avctx->active_thread_type & FF_THREAD_FRAME)) {
        if (HAVE_THREADS && avctx->active_thread_type & FF_THREAD_FRAME)
            ret = ff_thread_decode_frame(avctx, picture, got_picture_ptr,
                                         avpkt);
        else {
            ret = avctx->codec->decode(avctx, picture, got_picture_ptr,
                                       avpkt);
            picture->pkt_dts = avpkt->dts;
            /* get_buffer is supposed to set frame parameters */
            if (!(avctx->codec->capabilities & CODEC_CAP_DR1)) {
                picture->sample_aspect_ratio = avctx->sample_aspect_ratio;
                picture->width               = avctx->width;
                picture->height              = avctx->height;
                picture->format              = avctx->pix_fmt;
            }
        }

        emms_c(); //needed to avoid an emms_c() call before every return;

        if (*got_picture_ptr) {
            if (!avctx->refcounted_frames) {
                int err = unrefcount_frame(avci, picture);
                if (err < 0)
                    return err;
            }

            avctx->frame_number++;
        } else
            av_frame_unref(picture);
    } else
        ret = 0;

    return ret;
}

int attribute_align_arg avcodec_decode_audio4(AVCodecContext *avctx,
                                              AVFrame *frame,
                                              int *got_frame_ptr,
                                              AVPacket *avpkt)
{
    AVCodecInternal *avci = avctx->internal;
    int ret = 0;

    *got_frame_ptr = 0;

    avctx->internal->pkt = avpkt;

    if (!avpkt->data && avpkt->size) {
        av_log(avctx, AV_LOG_ERROR, "invalid packet: NULL data, size != 0\n");
        return AVERROR(EINVAL);
    }

    ret = apply_param_change(avctx, avpkt);
    if (ret < 0) {
        av_log(avctx, AV_LOG_ERROR, "Error applying parameter changes.\n");
        if (avctx->err_recognition & AV_EF_EXPLODE)
            return ret;
    }

    av_frame_unref(frame);

    if ((avctx->codec->capabilities & CODEC_CAP_DELAY) || avpkt->size) {
        ret = avctx->codec->decode(avctx, frame, got_frame_ptr, avpkt);
        if (ret >= 0 && *got_frame_ptr) {
            avctx->frame_number++;
            frame->pkt_dts = avpkt->dts;
            if (frame->format == AV_SAMPLE_FMT_NONE)
                frame->format = avctx->sample_fmt;

            if (!avctx->refcounted_frames) {
                int err = unrefcount_frame(avci, frame);
                if (err < 0)
                    return err;
            }
        } else
            av_frame_unref(frame);
    }


    return ret;
}

int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
                             int *got_sub_ptr,
                             AVPacket *avpkt)
{
    int ret;

    avctx->internal->pkt = avpkt;
    *got_sub_ptr = 0;
    ret = avctx->codec->decode(avctx, sub, got_sub_ptr, avpkt);
    if (*got_sub_ptr)
        avctx->frame_number++;
    return ret;
}

void avsubtitle_free(AVSubtitle *sub)
{
    int i;

    for (i = 0; i < sub->num_rects; i++) {
        av_freep(&sub->rects[i]->pict.data[0]);
        av_freep(&sub->rects[i]->pict.data[1]);
        av_freep(&sub->rects[i]->pict.data[2]);
        av_freep(&sub->rects[i]->pict.data[3]);
        av_freep(&sub->rects[i]->text);
        av_freep(&sub->rects[i]->ass);
        av_freep(&sub->rects[i]);
    }

    av_freep(&sub->rects);

    memset(sub, 0, sizeof(AVSubtitle));
}

av_cold int avcodec_close(AVCodecContext *avctx)
{
    /* If there is a user-supplied mutex locking routine, call it. */
    if (lockmgr_cb) {
        if ((*lockmgr_cb)(&codec_mutex, AV_LOCK_OBTAIN))
            return -1;
    }

    entangled_thread_counter++;
    if (entangled_thread_counter != 1) {
        av_log(avctx, AV_LOG_ERROR, "insufficient thread locking around avcodec_open/close()\n");
        entangled_thread_counter--;
        return -1;
    }

    if (avcodec_is_open(avctx)) {
        FramePool *pool = avctx->internal->pool;
        int i;
        if (HAVE_THREADS && avctx->internal->thread_ctx)
            ff_thread_free(avctx);
        if (avctx->codec && avctx->codec->close)
            avctx->codec->close(avctx);
        avctx->coded_frame = NULL;
        av_frame_free(&avctx->internal->to_free);
        for (i = 0; i < FF_ARRAY_ELEMS(pool->pools); i++)
            av_buffer_pool_uninit(&pool->pools[i]);
        av_freep(&avctx->internal->pool);
        av_freep(&avctx->internal);
    }

    if (avctx->priv_data && avctx->codec && avctx->codec->priv_class)
        av_opt_free(avctx->priv_data);
    av_opt_free(avctx);
    av_freep(&avctx->priv_data);
    if (av_codec_is_encoder(avctx->codec))
        av_freep(&avctx->extradata);
    avctx->codec = NULL;
    avctx->active_thread_type = 0;
    entangled_thread_counter--;

    /* Release any user-supplied mutex. */
    if (lockmgr_cb) {
        (*lockmgr_cb)(&codec_mutex, AV_LOCK_RELEASE);
    }
    return 0;
}

static AVCodec *find_encdec(enum AVCodecID id, int encoder)
{
    AVCodec *p, *experimental = NULL;
    p = first_avcodec;
    while (p) {
        if ((encoder ? av_codec_is_encoder(p) : av_codec_is_decoder(p)) &&
            p->id == id) {
            if (p->capabilities & CODEC_CAP_EXPERIMENTAL && !experimental) {
                experimental = p;
            } else
                return p;
        }
        p = p->next;
    }
    return experimental;
}

AVCodec *avcodec_find_encoder(enum AVCodecID id)
{
    return find_encdec(id, 1);
}

AVCodec *avcodec_find_encoder_by_name(const char *name)
{
    AVCodec *p;
    if (!name)
        return NULL;
    p = first_avcodec;
    while (p) {
        if (av_codec_is_encoder(p) && strcmp(name, p->name) == 0)
            return p;
        p = p->next;
    }
    return NULL;
}

AVCodec *avcodec_find_decoder(enum AVCodecID id)
{
    return find_encdec(id, 0);
}

AVCodec *avcodec_find_decoder_by_name(const char *name)
{
    AVCodec *p;
    if (!name)
        return NULL;
    p = first_avcodec;
    while (p) {
        if (av_codec_is_decoder(p) && strcmp(name, p->name) == 0)
            return p;
        p = p->next;
    }
    return NULL;
}

static int get_bit_rate(AVCodecContext *ctx)
{
    int bit_rate;
    int bits_per_sample;

    switch (ctx->codec_type) {
    case AVMEDIA_TYPE_VIDEO:
    case AVMEDIA_TYPE_DATA:
    case AVMEDIA_TYPE_SUBTITLE:
    case AVMEDIA_TYPE_ATTACHMENT:
        bit_rate = ctx->bit_rate;
        break;
    case AVMEDIA_TYPE_AUDIO:
        bits_per_sample = av_get_bits_per_sample(ctx->codec_id);
        bit_rate = bits_per_sample ? ctx->sample_rate * ctx->channels * bits_per_sample : ctx->bit_rate;
        break;
    default:
        bit_rate = 0;
        break;
    }
    return bit_rate;
}

size_t av_get_codec_tag_string(char *buf, size_t buf_size, unsigned int codec_tag)
{
    int i, len, ret = 0;

#define TAG_PRINT(x)                                              \
    (((x) >= '0' && (x) <= '9') ||                                \
     ((x) >= 'a' && (x) <= 'z') || ((x) >= 'A' && (x) <= 'Z') ||  \
     ((x) == '.' || (x) == ' '))

    for (i = 0; i < 4; i++) {
        len = snprintf(buf, buf_size,
                       TAG_PRINT(codec_tag & 0xFF) ? "%c" : "[%d]", codec_tag & 0xFF);
        buf        += len;
        buf_size    = buf_size > len ? buf_size - len : 0;
        ret        += len;
        codec_tag >>= 8;
    }
    return ret;
}

void avcodec_string(char *buf, int buf_size, AVCodecContext *enc, int encode)
{
    const char *codec_name;
    const char *profile = NULL;
    const AVCodec *p;
    char buf1[32];
    int bitrate;
    AVRational display_aspect_ratio;

    if (enc->codec)
        p = enc->codec;
    else if (encode)
        p = avcodec_find_encoder(enc->codec_id);
    else
        p = avcodec_find_decoder(enc->codec_id);

    if (p) {
        codec_name = p->name;
        profile = av_get_profile_name(p, enc->profile);
    } else if (enc->codec_id == AV_CODEC_ID_MPEG2TS) {
        /* fake mpeg2 transport stream codec (currently not
         * registered) */
        codec_name = "mpeg2ts";
    } else if (enc->codec_name[0] != '\0') {
        codec_name = enc->codec_name;
    } else {
        /* output avi tags */
        char tag_buf[32];
        av_get_codec_tag_string(tag_buf, sizeof(tag_buf), enc->codec_tag);
        snprintf(buf1, sizeof(buf1), "%s / 0x%04X", tag_buf, enc->codec_tag);
        codec_name = buf1;
    }

    switch (enc->codec_type) {
    case AVMEDIA_TYPE_VIDEO:
        snprintf(buf, buf_size,
                 "Video: %s%s",
                 codec_name, enc->mb_decision ? " (hq)" : "");
        if (profile)
            snprintf(buf + strlen(buf), buf_size - strlen(buf),
                     " (%s)", profile);
        if (enc->pix_fmt != AV_PIX_FMT_NONE) {
            snprintf(buf + strlen(buf), buf_size - strlen(buf),
                     ", %s",
                     av_get_pix_fmt_name(enc->pix_fmt));
        }
        if (enc->width) {
            snprintf(buf + strlen(buf), buf_size - strlen(buf),
                     ", %dx%d",
                     enc->width, enc->height);
            if (enc->sample_aspect_ratio.num) {
                av_reduce(&display_aspect_ratio.num, &display_aspect_ratio.den,
                          enc->width * enc->sample_aspect_ratio.num,
                          enc->height * enc->sample_aspect_ratio.den,
                          1024 * 1024);
                snprintf(buf + strlen(buf), buf_size - strlen(buf),
                         " [PAR %d:%d DAR %d:%d]",
                         enc->sample_aspect_ratio.num, enc->sample_aspect_ratio.den,
                         display_aspect_ratio.num, display_aspect_ratio.den);
            }
            if (av_log_get_level() >= AV_LOG_DEBUG) {
                int g = av_gcd(enc->time_base.num, enc->time_base.den);
                snprintf(buf + strlen(buf), buf_size - strlen(buf),
                         ", %d/%d",
                         enc->time_base.num / g, enc->time_base.den / g);
            }
        }
        if (encode) {
            snprintf(buf + strlen(buf), buf_size - strlen(buf),
                     ", q=%d-%d", enc->qmin, enc->qmax);
        }
        break;
    case AVMEDIA_TYPE_AUDIO:
        snprintf(buf, buf_size,
                 "Audio: %s",
                 codec_name);
        if (profile)
            snprintf(buf + strlen(buf), buf_size - strlen(buf),
                     " (%s)", profile);
        if (enc->sample_rate) {
            snprintf(buf + strlen(buf), buf_size - strlen(buf),
                     ", %d Hz", enc->sample_rate);
        }
        av_strlcat(buf, ", ", buf_size);
        av_get_channel_layout_string(buf + strlen(buf), buf_size - strlen(buf), enc->channels, enc->channel_layout);
        if (enc->sample_fmt != AV_SAMPLE_FMT_NONE) {
            snprintf(buf + strlen(buf), buf_size - strlen(buf),
                     ", %s", av_get_sample_fmt_name(enc->sample_fmt));
        }
        break;
    case AVMEDIA_TYPE_DATA:
        snprintf(buf, buf_size, "Data: %s", codec_name);
        break;
    case AVMEDIA_TYPE_SUBTITLE:
        snprintf(buf, buf_size, "Subtitle: %s", codec_name);
        break;
    case AVMEDIA_TYPE_ATTACHMENT:
        snprintf(buf, buf_size, "Attachment: %s", codec_name);
        break;
    default:
        snprintf(buf, buf_size, "Invalid Codec type %d", enc->codec_type);
        return;
    }
    if (encode) {
        if (enc->flags & CODEC_FLAG_PASS1)
            snprintf(buf + strlen(buf), buf_size - strlen(buf),
                     ", pass 1");
        if (enc->flags & CODEC_FLAG_PASS2)
            snprintf(buf + strlen(buf), buf_size - strlen(buf),
                     ", pass 2");
    }
    bitrate = get_bit_rate(enc);
    if (bitrate != 0) {
        snprintf(buf + strlen(buf), buf_size - strlen(buf),
                 ", %d kb/s", bitrate / 1000);
    }
}

const char *av_get_profile_name(const AVCodec *codec, int profile)
{
    const AVProfile *p;
    if (profile == FF_PROFILE_UNKNOWN || !codec->profiles)
        return NULL;

    for (p = codec->profiles; p->profile != FF_PROFILE_UNKNOWN; p++)
        if (p->profile == profile)
            return p->name;

    return NULL;
}

unsigned avcodec_version(void)
{
    return LIBAVCODEC_VERSION_INT;
}

const char *avcodec_configuration(void)
{
    return LIBAV_CONFIGURATION;
}

const char *avcodec_license(void)
{
#define LICENSE_PREFIX "libavcodec license: "
    return LICENSE_PREFIX LIBAV_LICENSE + sizeof(LICENSE_PREFIX) - 1;
}

void avcodec_flush_buffers(AVCodecContext *avctx)
{
    if (HAVE_THREADS && avctx->active_thread_type & FF_THREAD_FRAME)
        ff_thread_flush(avctx);
    else if (avctx->codec->flush)
        avctx->codec->flush(avctx);

    if (!avctx->refcounted_frames)
        av_frame_unref(avctx->internal->to_free);
}

int av_get_exact_bits_per_sample(enum AVCodecID codec_id)
{
    switch (codec_id) {
    case AV_CODEC_ID_ADPCM_CT:
    case AV_CODEC_ID_ADPCM_IMA_APC:
    case AV_CODEC_ID_ADPCM_IMA_EA_SEAD:
    case AV_CODEC_ID_ADPCM_IMA_WS:
    case AV_CODEC_ID_ADPCM_G722:
    case AV_CODEC_ID_ADPCM_YAMAHA:
        return 4;
    case AV_CODEC_ID_PCM_ALAW:
    case AV_CODEC_ID_PCM_MULAW:
    case AV_CODEC_ID_PCM_S8:
    case AV_CODEC_ID_PCM_U8:
    case AV_CODEC_ID_PCM_ZORK:
        return 8;
    case AV_CODEC_ID_PCM_S16BE:
    case AV_CODEC_ID_PCM_S16LE:
    case AV_CODEC_ID_PCM_S16LE_PLANAR:
    case AV_CODEC_ID_PCM_U16BE:
    case AV_CODEC_ID_PCM_U16LE:
        return 16;
    case AV_CODEC_ID_PCM_S24DAUD:
    case AV_CODEC_ID_PCM_S24BE:
    case AV_CODEC_ID_PCM_S24LE:
    case AV_CODEC_ID_PCM_S24LE_PLANAR:
    case AV_CODEC_ID_PCM_U24BE:
    case AV_CODEC_ID_PCM_U24LE:
        return 24;
    case AV_CODEC_ID_PCM_S32BE:
    case AV_CODEC_ID_PCM_S32LE:
    case AV_CODEC_ID_PCM_S32LE_PLANAR:
    case AV_CODEC_ID_PCM_U32BE:
    case AV_CODEC_ID_PCM_U32LE:
    case AV_CODEC_ID_PCM_F32BE:
    case AV_CODEC_ID_PCM_F32LE:
        return 32;
    case AV_CODEC_ID_PCM_F64BE:
    case AV_CODEC_ID_PCM_F64LE:
        return 64;
    default:
        return 0;
    }
}

int av_get_bits_per_sample(enum AVCodecID codec_id)
{
    switch (codec_id) {
    case AV_CODEC_ID_ADPCM_SBPRO_2:
        return 2;
    case AV_CODEC_ID_ADPCM_SBPRO_3:
        return 3;
    case AV_CODEC_ID_ADPCM_SBPRO_4:
    case AV_CODEC_ID_ADPCM_IMA_WAV:
    case AV_CODEC_ID_ADPCM_IMA_QT:
    case AV_CODEC_ID_ADPCM_SWF:
    case AV_CODEC_ID_ADPCM_MS:
        return 4;
    default:
        return av_get_exact_bits_per_sample(codec_id);
    }
}

int av_get_audio_frame_duration(AVCodecContext *avctx, int frame_bytes)
{
    int id, sr, ch, ba, tag, bps;

    id  = avctx->codec_id;
    sr  = avctx->sample_rate;
    ch  = avctx->channels;
    ba  = avctx->block_align;
    tag = avctx->codec_tag;
    bps = av_get_exact_bits_per_sample(avctx->codec_id);

    /* codecs with an exact constant bits per sample */
    if (bps > 0 && ch > 0 && frame_bytes > 0)
        return (frame_bytes * 8) / (bps * ch);
    bps = avctx->bits_per_coded_sample;

    /* codecs with a fixed packet duration */
    switch (id) {
    case AV_CODEC_ID_ADPCM_ADX:    return   32;
    case AV_CODEC_ID_ADPCM_IMA_QT: return   64;
    case AV_CODEC_ID_ADPCM_EA_XAS: return  128;
    case AV_CODEC_ID_AMR_NB:
    case AV_CODEC_ID_GSM:
    case AV_CODEC_ID_QCELP:
    case AV_CODEC_ID_RA_144:
    case AV_CODEC_ID_RA_288:       return  160;
    case AV_CODEC_ID_IMC:          return  256;
    case AV_CODEC_ID_AMR_WB:
    case AV_CODEC_ID_GSM_MS:       return  320;
    case AV_CODEC_ID_MP1:          return  384;
    case AV_CODEC_ID_ATRAC1:       return  512;
    case AV_CODEC_ID_ATRAC3:       return 1024;
    case AV_CODEC_ID_MP2:
    case AV_CODEC_ID_MUSEPACK7:    return 1152;
    case AV_CODEC_ID_AC3:          return 1536;
    }

    if (sr > 0) {
        /* calc from sample rate */
        if (id == AV_CODEC_ID_TTA)
            return 256 * sr / 245;

        if (ch > 0) {
            /* calc from sample rate and channels */
            if (id == AV_CODEC_ID_BINKAUDIO_DCT)
                return (480 << (sr / 22050)) / ch;
        }
    }

    if (ba > 0) {
        /* calc from block_align */
        if (id == AV_CODEC_ID_SIPR) {
            switch (ba) {
            case 20: return 160;
            case 19: return 144;
            case 29: return 288;
            case 37: return 480;
            }
        } else if (id == AV_CODEC_ID_ILBC) {
            switch (ba) {
            case 38: return 160;
            case 50: return 240;
            }
        }
    }

    if (frame_bytes > 0) {
        /* calc from frame_bytes only */
        if (id == AV_CODEC_ID_TRUESPEECH)
            return 240 * (frame_bytes / 32);
        if (id == AV_CODEC_ID_NELLYMOSER)
            return 256 * (frame_bytes / 64);

        if (bps > 0) {
            /* calc from frame_bytes and bits_per_coded_sample */
            if (id == AV_CODEC_ID_ADPCM_G726)
                return frame_bytes * 8 / bps;
        }

        if (ch > 0) {
            /* calc from frame_bytes and channels */
            switch (id) {
            case AV_CODEC_ID_ADPCM_4XM:
            case AV_CODEC_ID_ADPCM_IMA_ISS:
                return (frame_bytes - 4 * ch) * 2 / ch;
            case AV_CODEC_ID_ADPCM_IMA_SMJPEG:
                return (frame_bytes - 4) * 2 / ch;
            case AV_CODEC_ID_ADPCM_IMA_AMV:
                return (frame_bytes - 8) * 2 / ch;
            case AV_CODEC_ID_ADPCM_XA:
                return (frame_bytes / 128) * 224 / ch;
            case AV_CODEC_ID_INTERPLAY_DPCM:
                return (frame_bytes - 6 - ch) / ch;
            case AV_CODEC_ID_ROQ_DPCM:
                return (frame_bytes - 8) / ch;
            case AV_CODEC_ID_XAN_DPCM:
                return (frame_bytes - 2 * ch) / ch;
            case AV_CODEC_ID_MACE3:
                return 3 * frame_bytes / ch;
            case AV_CODEC_ID_MACE6:
                return 6 * frame_bytes / ch;
            case AV_CODEC_ID_PCM_LXF:
                return 2 * (frame_bytes / (5 * ch));
            }

            if (tag) {
                /* calc from frame_bytes, channels, and codec_tag */
                if (id == AV_CODEC_ID_SOL_DPCM) {
                    if (tag == 3)
                        return frame_bytes / ch;
                    else
                        return frame_bytes * 2 / ch;
                }
            }

            if (ba > 0) {
                /* calc from frame_bytes, channels, and block_align */
                int blocks = frame_bytes / ba;
                switch (avctx->codec_id) {
                case AV_CODEC_ID_ADPCM_IMA_WAV:
                    return blocks * (1 + (ba - 4 * ch) / (4 * ch) * 8);
                case AV_CODEC_ID_ADPCM_IMA_DK3:
                    return blocks * (((ba - 16) * 2 / 3 * 4) / ch);
                case AV_CODEC_ID_ADPCM_IMA_DK4:
                    return blocks * (1 + (ba - 4 * ch) * 2 / ch);
                case AV_CODEC_ID_ADPCM_MS:
                    return blocks * (2 + (ba - 7 * ch) * 2 / ch);
                }
            }

            if (bps > 0) {
                /* calc from frame_bytes, channels, and bits_per_coded_sample */
                switch (avctx->codec_id) {
                case AV_CODEC_ID_PCM_DVD:
                    return 2 * (frame_bytes / ((bps * 2 / 8) * ch));
                case AV_CODEC_ID_PCM_BLURAY:
                    return frame_bytes / ((FFALIGN(ch, 2) * bps) / 8);
                case AV_CODEC_ID_S302M:
                    return 2 * (frame_bytes / ((bps + 4) / 4)) / ch;
                }
            }
        }
    }

    return 0;
}

#if !HAVE_THREADS
int ff_thread_init(AVCodecContext *s)
{
    return -1;
}

#endif

unsigned int av_xiphlacing(unsigned char *s, unsigned int v)
{
    unsigned int n = 0;

    while (v >= 0xff) {
        *s++ = 0xff;
        v -= 0xff;
        n++;
    }
    *s = v;
    n++;
    return n;
}

int ff_match_2uint16(const uint16_t(*tab)[2], int size, int a, int b)
{
    int i;
    for (i = 0; i < size && !(tab[i][0] == a && tab[i][1] == b); i++) ;
    return i;
}

#if FF_API_MISSING_SAMPLE
FF_DISABLE_DEPRECATION_WARNINGS
void av_log_missing_feature(void *avc, const char *feature, int want_sample)
{
    av_log(avc, AV_LOG_WARNING, "%s is not implemented. Update your Libav "
            "version to the newest one from Git. If the problem still "
            "occurs, it means that your file has a feature which has not "
            "been implemented.\n", feature);
    if(want_sample)
        av_log_ask_for_sample(avc, NULL);
}

void av_log_ask_for_sample(void *avc, const char *msg, ...)
{
    va_list argument_list;

    va_start(argument_list, msg);

    if (msg)
        av_vlog(avc, AV_LOG_WARNING, msg, argument_list);
    av_log(avc, AV_LOG_WARNING, "If you want to help, upload a sample "
            "of this file to ftp://upload.libav.org/incoming/ "
            "and contact the libav-devel mailing list.\n");

    va_end(argument_list);
}
FF_ENABLE_DEPRECATION_WARNINGS
#endif /* FF_API_MISSING_SAMPLE */

static AVHWAccel *first_hwaccel = NULL;

void av_register_hwaccel(AVHWAccel *hwaccel)
{
    AVHWAccel **p = &first_hwaccel;
    while (*p)
        p = &(*p)->next;
    *p = hwaccel;
    hwaccel->next = NULL;
}

AVHWAccel *av_hwaccel_next(AVHWAccel *hwaccel)
{
    return hwaccel ? hwaccel->next : first_hwaccel;
}

AVHWAccel *ff_find_hwaccel(AVCodecContext *avctx)
{
    enum AVCodecID codec_id = avctx->codec->id;
    enum AVPixelFormat pix_fmt = avctx->pix_fmt;

    AVHWAccel *hwaccel = NULL;

    while ((hwaccel = av_hwaccel_next(hwaccel)))
        if (hwaccel->id == codec_id
            && hwaccel->pix_fmt == pix_fmt)
            return hwaccel;
    return NULL;
}

int av_lockmgr_register(int (*cb)(void **mutex, enum AVLockOp op))
{
    if (lockmgr_cb) {
        if (lockmgr_cb(&codec_mutex, AV_LOCK_DESTROY))
            return -1;
        if (lockmgr_cb(&avformat_mutex, AV_LOCK_DESTROY))
            return -1;
    }

    lockmgr_cb = cb;

    if (lockmgr_cb) {
        if (lockmgr_cb(&codec_mutex, AV_LOCK_CREATE))
            return -1;
        if (lockmgr_cb(&avformat_mutex, AV_LOCK_CREATE))
            return -1;
    }
    return 0;
}

int avpriv_lock_avformat(void)
{
    if (lockmgr_cb) {
        if ((*lockmgr_cb)(&avformat_mutex, AV_LOCK_OBTAIN))
            return -1;
    }
    return 0;
}

int avpriv_unlock_avformat(void)
{
    if (lockmgr_cb) {
        if ((*lockmgr_cb)(&avformat_mutex, AV_LOCK_RELEASE))
            return -1;
    }
    return 0;
}

unsigned int avpriv_toupper4(unsigned int x)
{
    return av_toupper(x & 0xFF) +
          (av_toupper((x >>  8) & 0xFF) << 8)  +
          (av_toupper((x >> 16) & 0xFF) << 16) +
          (av_toupper((x >> 24) & 0xFF) << 24);
}

int ff_thread_ref_frame(ThreadFrame *dst, ThreadFrame *src)
{
    int ret;

    dst->owner = src->owner;

    ret = av_frame_ref(dst->f, src->f);
    if (ret < 0)
        return ret;

    if (src->progress &&
        !(dst->progress = av_buffer_ref(src->progress))) {
        ff_thread_release_buffer(dst->owner, dst);
        return AVERROR(ENOMEM);
    }

    return 0;
}

#if !HAVE_THREADS

int ff_thread_get_buffer(AVCodecContext *avctx, ThreadFrame *f, int flags)
{
    f->owner = avctx;
    return ff_get_buffer(avctx, f->f, flags);
}

void ff_thread_release_buffer(AVCodecContext *avctx, ThreadFrame *f)
{
    av_frame_unref(f->f);
}

void ff_thread_finish_setup(AVCodecContext *avctx)
{
}

void ff_thread_report_progress(ThreadFrame *f, int progress, int field)
{
}

void ff_thread_await_progress(ThreadFrame *f, int progress, int field)
{
}

#endif

enum AVMediaType avcodec_get_type(enum AVCodecID codec_id)
{
    if (codec_id <= AV_CODEC_ID_NONE)
        return AVMEDIA_TYPE_UNKNOWN;
    else if (codec_id < AV_CODEC_ID_FIRST_AUDIO)
        return AVMEDIA_TYPE_VIDEO;
    else if (codec_id < AV_CODEC_ID_FIRST_SUBTITLE)
        return AVMEDIA_TYPE_AUDIO;
    else if (codec_id < AV_CODEC_ID_FIRST_UNKNOWN)
        return AVMEDIA_TYPE_SUBTITLE;

    return AVMEDIA_TYPE_UNKNOWN;
}

int avcodec_is_open(AVCodecContext *s)
{
    return !!s->internal;
}

const uint8_t *avpriv_find_start_code(const uint8_t *restrict p,
                                      const uint8_t *end,
                                      uint32_t * restrict state)
{
    int i;

    assert(p <= end);
    if (p >= end)
        return end;

    for (i = 0; i < 3; i++) {
        uint32_t tmp = *state << 8;
        *state = tmp + *(p++);
        if (tmp == 0x100 || p == end)
            return p;
    }

    while (p < end) {
        if      (p[-1] > 1      ) p += 3;
        else if (p[-2]          ) p += 2;
        else if (p[-3]|(p[-1]-1)) p++;
        else {
            p++;
            break;
        }
    }

    p = FFMIN(p, end) - 4;
    *state = AV_RB32(p);

    return p + 4;
}