FFmpeg/libavcodec/lcldec.c

/*
 * LCL (LossLess Codec Library) Codec
 * Copyright (c) 2002-2004 Roberto Togni
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg 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.
 *
 * FFmpeg 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 FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file libavcodec/lcldec.c
 * LCL (LossLess Codec Library) Video Codec
 * Decoder for MSZH and ZLIB codecs
 * Experimental encoder for ZLIB RGB24
 *
 * Fourcc: MSZH, ZLIB
 *
 * Original Win32 dll:
 * Ver2.23 By Kenji Oshima 2000.09.20
 * avimszh.dll, avizlib.dll
 *
 * A description of the decoding algorithm can be found here:
 *   http://www.pcisys.net/~melanson/codecs
 *
 * Supports: BGR24 (RGB 24bpp)
 *
 */

#include <stdio.h>
#include <stdlib.h>

#include "avcodec.h"
#include "get_bits.h"
#include "lcl.h"

#if CONFIG_ZLIB_DECODER
#include <zlib.h>
#endif

/*
 * Decoder context
 */
typedef struct LclDecContext {
    AVFrame pic;

    // Image type
    int imgtype;
    // Compression type
    int compression;
    // Flags
    int flags;
    // Decompressed data size
    unsigned int decomp_size;
    // Decompression buffer
    unsigned char* decomp_buf;
#if CONFIG_ZLIB_DECODER
    z_stream zstream;
#endif
} LclDecContext;


static unsigned int mszh_decomp(unsigned char * srcptr, int srclen, unsigned char * destptr, unsigned int destsize)
{
    unsigned char *destptr_bak = destptr;
    unsigned char *destptr_end = destptr + destsize;
    unsigned char mask = 0;
    unsigned char maskbit = 0;
    unsigned int ofs, cnt;

    while (srclen > 0 && destptr < destptr_end) {
        if (maskbit == 0) {
            mask = *srcptr++;
            maskbit = 8;
            srclen--;
            continue;
        }
        if ((mask & (1 << (--maskbit))) == 0) {
            if (destptr + 4 > destptr_end)
                break;
            AV_WN32(destptr, AV_RN32(srcptr));
            srclen -= 4;
            destptr += 4;
            srcptr += 4;
        } else {
            ofs = *srcptr++;
            cnt = *srcptr++;
            ofs += cnt * 256;
            cnt = ((cnt >> 3) & 0x1f) + 1;
            ofs &= 0x7ff;
            srclen -= 2;
            cnt *= 4;
            if (destptr + cnt > destptr_end) {
                cnt =  destptr_end - destptr;
            }
            for (; cnt > 0; cnt--) {
                *destptr = *(destptr - ofs);
                destptr++;
            }
        }
    }

    return destptr - destptr_bak;
}



/*
 *
 * Decode a frame
 *
 */
static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    LclDecContext * const c = avctx->priv_data;
    unsigned char *encoded = (unsigned char *)buf;
    unsigned int pixel_ptr;
    int row, col;
    unsigned char *outptr;
    uint8_t *y_out, *u_out, *v_out;
    unsigned int width = avctx->width; // Real image width
    unsigned int height = avctx->height; // Real image height
    unsigned int mszh_dlen;
    unsigned char yq, y1q, uq, vq;
    int uqvq;
    unsigned int mthread_inlen, mthread_outlen;
#if CONFIG_ZLIB_DECODER
    int zret; // Zlib return code
#endif
    unsigned int len = buf_size;

    if(c->pic.data[0])
        avctx->release_buffer(avctx, &c->pic);

    c->pic.reference = 0;
    c->pic.buffer_hints = FF_BUFFER_HINTS_VALID;
    if(avctx->get_buffer(avctx, &c->pic) < 0){
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return -1;
    }

    outptr = c->pic.data[0]; // Output image pointer

    /* Decompress frame */
    switch (avctx->codec_id) {
    case CODEC_ID_MSZH:
        switch (c->compression) {
        case COMP_MSZH:
            if (c->flags & FLAG_MULTITHREAD) {
                mthread_inlen = *(unsigned int*)encoded;
                mthread_outlen = *(unsigned int*)(encoded+4);
                if (mthread_outlen > c->decomp_size) // this should not happen
                    mthread_outlen = c->decomp_size;
                mszh_dlen = mszh_decomp(encoded + 8, mthread_inlen, c->decomp_buf, c->decomp_size);
                if (mthread_outlen != mszh_dlen) {
                    av_log(avctx, AV_LOG_ERROR, "Mthread1 decoded size differs (%d != %d)\n",
                           mthread_outlen, mszh_dlen);
                    return -1;
                }
                mszh_dlen = mszh_decomp(encoded + 8 + mthread_inlen, len - mthread_inlen,
                                        c->decomp_buf + mthread_outlen, c->decomp_size - mthread_outlen);
                if (mthread_outlen != mszh_dlen) {
                    av_log(avctx, AV_LOG_ERROR, "Mthread2 decoded size differs (%d != %d)\n",
                           mthread_outlen, mszh_dlen);
                    return -1;
                }
                encoded = c->decomp_buf;
                len = c->decomp_size;
            } else {
                mszh_dlen = mszh_decomp(encoded, len, c->decomp_buf, c->decomp_size);
                if (c->decomp_size != mszh_dlen) {
                    av_log(avctx, AV_LOG_ERROR, "Decoded size differs (%d != %d)\n",
                           c->decomp_size, mszh_dlen);
                    return -1;
                }
                encoded = c->decomp_buf;
                len = mszh_dlen;
            }
            break;
        case COMP_MSZH_NOCOMP:
            break;
        default:
            av_log(avctx, AV_LOG_ERROR, "BUG! Unknown MSZH compression in frame decoder.\n");
            return -1;
        }
        break;
    case CODEC_ID_ZLIB:
#if CONFIG_ZLIB_DECODER
        /* Using the original dll with normal compression (-1) and RGB format
         * gives a file with ZLIB fourcc, but frame is really uncompressed.
         * To be sure that's true check also frame size */
        if (c->compression == COMP_ZLIB_NORMAL && c->imgtype == IMGTYPE_RGB24 &&
            len == width * height * 3)
            break;
        zret = inflateReset(&c->zstream);
        if (zret != Z_OK) {
            av_log(avctx, AV_LOG_ERROR, "Inflate reset error: %d\n", zret);
            return -1;
        }
        if (c->flags & FLAG_MULTITHREAD) {
            mthread_inlen = *(unsigned int*)encoded;
            mthread_outlen = *(unsigned int*)(encoded+4);
            if (mthread_outlen > c->decomp_size)
                mthread_outlen = c->decomp_size;
            c->zstream.next_in = encoded + 8;
            c->zstream.avail_in = mthread_inlen;
            c->zstream.next_out = c->decomp_buf;
            c->zstream.avail_out = c->decomp_size;
            zret = inflate(&c->zstream, Z_FINISH);
            if (zret != Z_OK && zret != Z_STREAM_END) {
                av_log(avctx, AV_LOG_ERROR, "Mthread1 inflate error: %d\n", zret);
                return -1;
            }
            if (mthread_outlen != (unsigned int)c->zstream.total_out) {
                av_log(avctx, AV_LOG_ERROR, "Mthread1 decoded size differs (%u != %lu)\n",
                       mthread_outlen, c->zstream.total_out);
                return -1;
            }
            zret = inflateReset(&c->zstream);
            if (zret != Z_OK) {
                av_log(avctx, AV_LOG_ERROR, "Mthread2 inflate reset error: %d\n", zret);
                return -1;
            }
            c->zstream.next_in = encoded + 8 + mthread_inlen;
            c->zstream.avail_in = len - mthread_inlen;
            c->zstream.next_out = c->decomp_buf + mthread_outlen;
            c->zstream.avail_out = c->decomp_size - mthread_outlen;
            zret = inflate(&c->zstream, Z_FINISH);
            if (zret != Z_OK && zret != Z_STREAM_END) {
                av_log(avctx, AV_LOG_ERROR, "Mthread2 inflate error: %d\n", zret);
                return -1;
            }
            if (mthread_outlen != (unsigned int)c->zstream.total_out) {
                av_log(avctx, AV_LOG_ERROR, "Mthread2 decoded size differs (%d != %lu)\n",
                       mthread_outlen, c->zstream.total_out);
                return -1;
            }
        } else {
            c->zstream.next_in = encoded;
            c->zstream.avail_in = len;
            c->zstream.next_out = c->decomp_buf;
            c->zstream.avail_out = c->decomp_size;
            zret = inflate(&c->zstream, Z_FINISH);
            if (zret != Z_OK && zret != Z_STREAM_END) {
                av_log(avctx, AV_LOG_ERROR, "Inflate error: %d\n", zret);
                return -1;
            }
            if (c->decomp_size != (unsigned int)c->zstream.total_out) {
                av_log(avctx, AV_LOG_ERROR, "Decoded size differs (%d != %lu)\n",
                       c->decomp_size, c->zstream.total_out);
                return -1;
            }
        }
        encoded = c->decomp_buf;
        len = c->decomp_size;
#else
        av_log(avctx, AV_LOG_ERROR, "BUG! Zlib support not compiled in frame decoder.\n");
        return -1;
#endif
        break;
    default:
        av_log(avctx, AV_LOG_ERROR, "BUG! Unknown codec in frame decoder compression switch.\n");
        return -1;
    }


    /* Apply PNG filter */
    if (avctx->codec_id == CODEC_ID_ZLIB && (c->flags & FLAG_PNGFILTER)) {
        switch (c->imgtype) {
        case IMGTYPE_YUV111:
        case IMGTYPE_RGB24:
            for (row = 0; row < height; row++) {
                pixel_ptr = row * width * 3;
                yq = encoded[pixel_ptr++];
                uqvq = AV_RL16(encoded+pixel_ptr);
                pixel_ptr += 2;
                for (col = 1; col < width; col++) {
                    encoded[pixel_ptr] = yq -= encoded[pixel_ptr];
                    uqvq -= AV_RL16(encoded+pixel_ptr+1);
                    AV_WL16(encoded+pixel_ptr+1, uqvq);
                    pixel_ptr += 3;
                }
            }
            break;
        case IMGTYPE_YUV422:
            for (row = 0; row < height; row++) {
                pixel_ptr = row * width * 2;
                yq = uq = vq =0;
                for (col = 0; col < width/4; col++) {
                    encoded[pixel_ptr] = yq -= encoded[pixel_ptr];
                    encoded[pixel_ptr+1] = yq -= encoded[pixel_ptr+1];
                    encoded[pixel_ptr+2] = yq -= encoded[pixel_ptr+2];
                    encoded[pixel_ptr+3] = yq -= encoded[pixel_ptr+3];
                    encoded[pixel_ptr+4] = uq -= encoded[pixel_ptr+4];
                    encoded[pixel_ptr+5] = uq -= encoded[pixel_ptr+5];
                    encoded[pixel_ptr+6] = vq -= encoded[pixel_ptr+6];
                    encoded[pixel_ptr+7] = vq -= encoded[pixel_ptr+7];
                    pixel_ptr += 8;
                }
            }
            break;
        case IMGTYPE_YUV411:
            for (row = 0; row < height; row++) {
                pixel_ptr = row * width / 2 * 3;
                yq = uq = vq =0;
                for (col = 0; col < width/4; col++) {
                    encoded[pixel_ptr] = yq -= encoded[pixel_ptr];
                    encoded[pixel_ptr+1] = yq -= encoded[pixel_ptr+1];
                    encoded[pixel_ptr+2] = yq -= encoded[pixel_ptr+2];
                    encoded[pixel_ptr+3] = yq -= encoded[pixel_ptr+3];
                    encoded[pixel_ptr+4] = uq -= encoded[pixel_ptr+4];
                    encoded[pixel_ptr+5] = vq -= encoded[pixel_ptr+5];
                    pixel_ptr += 6;
                }
            }
            break;
        case IMGTYPE_YUV211:
            for (row = 0; row < height; row++) {
                pixel_ptr = row * width * 2;
                yq = uq = vq =0;
                for (col = 0; col < width/2; col++) {
                    encoded[pixel_ptr] = yq -= encoded[pixel_ptr];
                    encoded[pixel_ptr+1] = yq -= encoded[pixel_ptr+1];
                    encoded[pixel_ptr+2] = uq -= encoded[pixel_ptr+2];
                    encoded[pixel_ptr+3] = vq -= encoded[pixel_ptr+3];
                    pixel_ptr += 4;
                }
            }
            break;
        case IMGTYPE_YUV420:
            for (row = 0; row < height/2; row++) {
                pixel_ptr = row * width * 3;
                yq = y1q = uq = vq =0;
                for (col = 0; col < width/2; col++) {
                    encoded[pixel_ptr] = yq -= encoded[pixel_ptr];
                    encoded[pixel_ptr+1] = yq -= encoded[pixel_ptr+1];
                    encoded[pixel_ptr+2] = y1q -= encoded[pixel_ptr+2];
                    encoded[pixel_ptr+3] = y1q -= encoded[pixel_ptr+3];
                    encoded[pixel_ptr+4] = uq -= encoded[pixel_ptr+4];
                    encoded[pixel_ptr+5] = vq -= encoded[pixel_ptr+5];
                    pixel_ptr += 6;
                }
            }
            break;
        default:
            av_log(avctx, AV_LOG_ERROR, "BUG! Unknown imagetype in pngfilter switch.\n");
            return -1;
        }
    }

    /* Convert colorspace */
    y_out = c->pic.data[0] + (height - 1) * c->pic.linesize[0];
    u_out = c->pic.data[1] + (height - 1) * c->pic.linesize[1];
    v_out = c->pic.data[2] + (height - 1) * c->pic.linesize[2];
    switch (c->imgtype) {
    case IMGTYPE_YUV111:
        for (row = 0; row < height; row++) {
            for (col = 0; col < width; col++) {
                y_out[col] = *encoded++;
                u_out[col] = *encoded++ + 128;
                v_out[col] = *encoded++ + 128;
            }
            y_out -= c->pic.linesize[0];
            u_out -= c->pic.linesize[1];
            v_out -= c->pic.linesize[2];
        }
        break;
    case IMGTYPE_YUV422:
        for (row = 0; row < height; row++) {
            for (col = 0; col < width - 3; col += 4) {
                memcpy(y_out + col, encoded, 4);
                encoded += 4;
                u_out[ col >> 1     ] = *encoded++ + 128;
                u_out[(col >> 1) + 1] = *encoded++ + 128;
                v_out[ col >> 1     ] = *encoded++ + 128;
                v_out[(col >> 1) + 1] = *encoded++ + 128;
            }
            y_out -= c->pic.linesize[0];
            u_out -= c->pic.linesize[1];
            v_out -= c->pic.linesize[2];
        }
        break;
    case IMGTYPE_RGB24:
        for (row = height - 1; row >= 0; row--) {
            pixel_ptr = row * c->pic.linesize[0];
            memcpy(outptr + pixel_ptr, encoded, 3 * width);
            encoded += 3 * width;
        }
        break;
    case IMGTYPE_YUV411:
        for (row = 0; row < height; row++) {
            for (col = 0; col < width - 3; col += 4) {
                memcpy(y_out + col, encoded, 4);
                encoded += 4;
                u_out[col >> 2] = *encoded++ + 128;
                v_out[col >> 2] = *encoded++ + 128;
            }
            y_out -= c->pic.linesize[0];
            u_out -= c->pic.linesize[1];
            v_out -= c->pic.linesize[2];
        }
        break;
    case IMGTYPE_YUV211:
        for (row = 0; row < height; row++) {
            for (col = 0; col < width - 1; col += 2) {
                memcpy(y_out + col, encoded, 2);
                encoded += 2;
                u_out[col >> 1] = *encoded++ + 128;
                v_out[col >> 1] = *encoded++ + 128;
            }
            y_out -= c->pic.linesize[0];
            u_out -= c->pic.linesize[1];
            v_out -= c->pic.linesize[2];
        }
        break;
    case IMGTYPE_YUV420:
        u_out = c->pic.data[1] + ((height >> 1) - 1) * c->pic.linesize[1];
        v_out = c->pic.data[2] + ((height >> 1) - 1) * c->pic.linesize[2];
        for (row = 0; row < height - 1; row += 2) {
            for (col = 0; col < width - 1; col += 2) {
                memcpy(y_out + col, encoded, 2);
                encoded += 2;
                memcpy(y_out + col - c->pic.linesize[0], encoded, 2);
                encoded += 2;
                u_out[col >> 1] = *encoded++ + 128;
                v_out[col >> 1] = *encoded++ + 128;
            }
            y_out -= c->pic.linesize[0] << 1;
            u_out -= c->pic.linesize[1];
            v_out -= c->pic.linesize[2];
        }
        break;
    default:
        av_log(avctx, AV_LOG_ERROR, "BUG! Unknown imagetype in image decoder.\n");
        return -1;
    }

    *data_size = sizeof(AVFrame);
    *(AVFrame*)data = c->pic;

    /* always report that the buffer was completely consumed */
    return buf_size;
}

/*
 *
 * Init lcl decoder
 *
 */
static av_cold int decode_init(AVCodecContext *avctx)
{
    LclDecContext * const c = avctx->priv_data;
    unsigned int basesize = avctx->width * avctx->height;
    unsigned int max_basesize = ((avctx->width + 3) & ~3) * ((avctx->height + 3) & ~3);
    unsigned int max_decomp_size;
    int zret; // Zlib return code

    c->pic.data[0] = NULL;

#if CONFIG_ZLIB_DECODER
    // Needed if zlib unused or init aborted before inflateInit
    memset(&c->zstream, 0, sizeof(z_stream));
#endif

    if (avctx->extradata_size < 8) {
        av_log(avctx, AV_LOG_ERROR, "Extradata size too small.\n");
        return 1;
    }

    if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) {
        return 1;
    }

    /* Check codec type */
    if ((avctx->codec_id == CODEC_ID_MSZH  && avctx->extradata[7] != CODEC_MSZH) ||
        (avctx->codec_id == CODEC_ID_ZLIB  && avctx->extradata[7] != CODEC_ZLIB)) {
        av_log(avctx, AV_LOG_ERROR, "Codec id and codec type mismatch. This should not happen.\n");
    }

    /* Detect image type */
    switch (c->imgtype = avctx->extradata[4]) {
    case IMGTYPE_YUV111:
        c->decomp_size = basesize * 3;
        max_decomp_size = max_basesize * 3;
        avctx->pix_fmt = PIX_FMT_YUV444P;
        av_log(avctx, AV_LOG_INFO, "Image type is YUV 1:1:1.\n");
        break;
    case IMGTYPE_YUV422:
        c->decomp_size = basesize * 2;
        max_decomp_size = max_basesize * 2;
        avctx->pix_fmt = PIX_FMT_YUV422P;
        av_log(avctx, AV_LOG_INFO, "Image type is YUV 4:2:2.\n");
        break;
    case IMGTYPE_RGB24:
        c->decomp_size = basesize * 3;
        max_decomp_size = max_basesize * 3;
        avctx->pix_fmt = PIX_FMT_BGR24;
        av_log(avctx, AV_LOG_INFO, "Image type is RGB 24.\n");
        break;
    case IMGTYPE_YUV411:
        c->decomp_size = basesize / 2 * 3;
        max_decomp_size = max_basesize / 2 * 3;
        avctx->pix_fmt = PIX_FMT_YUV411P;
        av_log(avctx, AV_LOG_INFO, "Image type is YUV 4:1:1.\n");
        break;
    case IMGTYPE_YUV211:
        c->decomp_size = basesize * 2;
        max_decomp_size = max_basesize * 2;
        avctx->pix_fmt = PIX_FMT_YUV422P;
        av_log(avctx, AV_LOG_INFO, "Image type is YUV 2:1:1.\n");
        break;
    case IMGTYPE_YUV420:
        c->decomp_size = basesize / 2 * 3;
        max_decomp_size = max_basesize / 2 * 3;
        avctx->pix_fmt = PIX_FMT_YUV420P;
        av_log(avctx, AV_LOG_INFO, "Image type is YUV 4:2:0.\n");
        break;
    default:
        av_log(avctx, AV_LOG_ERROR, "Unsupported image format %d.\n", c->imgtype);
        return 1;
    }

    /* Detect compression method */
    c->compression = avctx->extradata[5];
    switch (avctx->codec_id) {
    case CODEC_ID_MSZH:
        switch (c->compression) {
        case COMP_MSZH:
            av_log(avctx, AV_LOG_INFO, "Compression enabled.\n");
            break;
        case COMP_MSZH_NOCOMP:
            c->decomp_size = 0;
            av_log(avctx, AV_LOG_INFO, "No compression.\n");
            break;
        default:
            av_log(avctx, AV_LOG_ERROR, "Unsupported compression format for MSZH (%d).\n", c->compression);
            return 1;
        }
        break;
    case CODEC_ID_ZLIB:
#if CONFIG_ZLIB_DECODER
        switch (c->compression) {
        case COMP_ZLIB_HISPEED:
            av_log(avctx, AV_LOG_INFO, "High speed compression.\n");
            break;
        case COMP_ZLIB_HICOMP:
            av_log(avctx, AV_LOG_INFO, "High compression.\n");
            break;
        case COMP_ZLIB_NORMAL:
            av_log(avctx, AV_LOG_INFO, "Normal compression.\n");
            break;
        default:
            if (c->compression < Z_NO_COMPRESSION || c->compression > Z_BEST_COMPRESSION) {
                av_log(avctx, AV_LOG_ERROR, "Unsupported compression level for ZLIB: (%d).\n", c->compression);
                return 1;
            }
            av_log(avctx, AV_LOG_INFO, "Compression level for ZLIB: (%d).\n", c->compression);
        }
#else
        av_log(avctx, AV_LOG_ERROR, "Zlib support not compiled.\n");
        return 1;
#endif
        break;
    default:
        av_log(avctx, AV_LOG_ERROR, "BUG! Unknown codec in compression switch.\n");
        return 1;
    }

    /* Allocate decompression buffer */
    if (c->decomp_size) {
        if ((c->decomp_buf = av_malloc(max_decomp_size)) == NULL) {
            av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
            return 1;
        }
    }

    /* Detect flags */
    c->flags = avctx->extradata[6];
    if (c->flags & FLAG_MULTITHREAD)
        av_log(avctx, AV_LOG_INFO, "Multithread encoder flag set.\n");
    if (c->flags & FLAG_NULLFRAME)
        av_log(avctx, AV_LOG_INFO, "Nullframe insertion flag set.\n");
    if ((avctx->codec_id == CODEC_ID_ZLIB) && (c->flags & FLAG_PNGFILTER))
        av_log(avctx, AV_LOG_INFO, "PNG filter flag set.\n");
    if (c->flags & FLAGMASK_UNUSED)
        av_log(avctx, AV_LOG_ERROR, "Unknown flag set (%d).\n", c->flags);

    /* If needed init zlib */
    if (avctx->codec_id == CODEC_ID_ZLIB) {
#if CONFIG_ZLIB_DECODER
        c->zstream.zalloc = Z_NULL;
        c->zstream.zfree = Z_NULL;
        c->zstream.opaque = Z_NULL;
        zret = inflateInit(&c->zstream);
        if (zret != Z_OK) {
            av_log(avctx, AV_LOG_ERROR, "Inflate init error: %d\n", zret);
            return 1;
        }
#else
        av_log(avctx, AV_LOG_ERROR, "Zlib support not compiled.\n");
        return 1;
#endif
    }

    return 0;
}

/*
 *
 * Uninit lcl decoder
 *
 */
static av_cold int decode_end(AVCodecContext *avctx)
{
    LclDecContext * const c = avctx->priv_data;

    if (c->pic.data[0])
        avctx->release_buffer(avctx, &c->pic);
#if CONFIG_ZLIB_DECODER
    inflateEnd(&c->zstream);
#endif

    return 0;
}

#if CONFIG_MSZH_DECODER
AVCodec mszh_decoder = {
    "mszh",
    CODEC_TYPE_VIDEO,
    CODEC_ID_MSZH,
    sizeof(LclDecContext),
    decode_init,
    NULL,
    decode_end,
    decode_frame,
    CODEC_CAP_DR1,
    .long_name = NULL_IF_CONFIG_SMALL("LCL (LossLess Codec Library) MSZH"),
};
#endif

#if CONFIG_ZLIB_DECODER
AVCodec zlib_decoder = {
    "zlib",
    CODEC_TYPE_VIDEO,
    CODEC_ID_ZLIB,
    sizeof(LclDecContext),
    decode_init,
    NULL,
    decode_end,
    decode_frame,
    CODEC_CAP_DR1,
    .long_name = NULL_IF_CONFIG_SMALL("LCL (LossLess Codec Library) ZLIB"),
};
#endif