FFmpeg/libavformat/wvenc.c

/*
 * 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
 */

#include "libavutil/attributes.h"

#include "apetag.h"
#include "avformat.h"
#include "wv.h"

typedef struct WvMuxContext {
    int64_t samples;
} WvMuxContext;

static av_cold int wv_write_header(AVFormatContext *ctx)
{
    if (ctx->nb_streams > 1 ||
        ctx->streams[0]->codecpar->codec_id != AV_CODEC_ID_WAVPACK) {
        av_log(ctx, AV_LOG_ERROR, "This muxer only supports a single WavPack stream.\n");
        return AVERROR(EINVAL);
    }

    return 0;
}

static int wv_write_packet(AVFormatContext *ctx, AVPacket *pkt)
{
    WvMuxContext *s = ctx->priv_data;
    WvHeader header;
    int ret;

    if (pkt->size < WV_HEADER_SIZE ||
        (ret = ff_wv_parse_header(&header, pkt->data)) < 0) {
        av_log(ctx, AV_LOG_ERROR, "Invalid WavPack packet.\n");
        return AVERROR(EINVAL);
    }
    s->samples += header.samples;

    avio_write(ctx->pb, pkt->data, pkt->size);

    return 0;
}

static av_cold int wv_write_trailer(AVFormatContext *ctx)
{
    WvMuxContext *s = ctx->priv_data;

    /* update total number of samples in the first block */
    if ((ctx->pb->seekable & AVIO_SEEKABLE_NORMAL) && s->samples &&
        s->samples < UINT32_MAX) {
        int64_t pos = avio_tell(ctx->pb);
        avio_seek(ctx->pb, 12, SEEK_SET);
        avio_wl32(ctx->pb, s->samples);
        avio_seek(ctx->pb, pos, SEEK_SET);
    }

    ff_ape_write_tag(ctx);
    return 0;
}

AVOutputFormat ff_wv_muxer = {
    .name              = "wv",
    .long_name         = NULL_IF_CONFIG_SMALL("raw WavPack"),
    .mime_type         = "audio/x-wavpack",
    .extensions        = "wv",
    .priv_data_size    = sizeof(WvMuxContext),
    .audio_codec       = AV_CODEC_ID_WAVPACK,
    .video_codec       = AV_CODEC_ID_NONE,
    .write_header      = wv_write_header,
    .write_packet      = wv_write_packet,
    .write_trailer     = wv_write_trailer,
    .flags             = AVFMT_NOTIMESTAMPS,
};