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ffmpeg / libavformat / yop.c @ e356fc57

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1 148bcae9 Mohamed Naufal
/**
2 ba87f080 Diego Biurrun
 * @file
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 * Psygnosis YOP demuxer
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 *
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 * Copyright (C) 2010 Mohamed Naufal Basheer <naufal11@gmail.com>
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 * derived from the code by
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 * Copyright (C) 2009 Thomas P. Higdon <thomas.p.higdon@gmail.com>
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "libavutil/intreadwrite.h"
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#include "avformat.h"
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typedef struct yop_dec_context {
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    AVPacket video_packet;
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    int odd_frame;
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    int frame_size;
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    int audio_block_length;
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    int palette_size;
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} YopDecContext;
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static int yop_probe(AVProbeData *probe_packet)
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{
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    if (AV_RB16(probe_packet->buf) == AV_RB16("YO")  &&
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        probe_packet->buf[6]                         &&
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        probe_packet->buf[7]                         &&
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        !(probe_packet->buf[8] & 1)                  &&
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        !(probe_packet->buf[10] & 1))
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        return AVPROBE_SCORE_MAX * 3 / 4;
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    return 0;
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}
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static int yop_read_header(AVFormatContext *s, AVFormatParameters *ap)
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{
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    YopDecContext *yop = s->priv_data;
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    AVIOContext *pb  = s->pb;
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    AVCodecContext *audio_dec, *video_dec;
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    AVStream *audio_stream, *video_stream;
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    int frame_rate, ret;
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    audio_stream = av_new_stream(s, 0);
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    video_stream = av_new_stream(s, 1);
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    // Extra data that will be passed to the decoder
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    video_stream->codec->extradata_size = 8;
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    video_stream->codec->extradata = av_mallocz(video_stream->codec->extradata_size +
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                                                FF_INPUT_BUFFER_PADDING_SIZE);
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    if (!video_stream->codec->extradata)
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        return AVERROR(ENOMEM);
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    // Audio
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    audio_dec               = audio_stream->codec;
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    audio_dec->codec_type   = AVMEDIA_TYPE_AUDIO;
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    audio_dec->codec_id     = CODEC_ID_ADPCM_IMA_WS;
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    audio_dec->channels     = 1;
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    audio_dec->sample_rate  = 22050;
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    // Video
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    video_dec               = video_stream->codec;
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    video_dec->codec_type   = AVMEDIA_TYPE_VIDEO;
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    video_dec->codec_id     = CODEC_ID_YOP;
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    avio_seek(pb, 6, SEEK_CUR);
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    frame_rate              = avio_r8(pb);
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    yop->frame_size         = avio_r8(pb) * 2048;
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    video_dec->width        = avio_rl16(pb);
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    video_dec->height       = avio_rl16(pb);
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    video_stream->sample_aspect_ratio = (AVRational){1, 2};
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    ret = avio_read(pb, video_dec->extradata, 8);
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    if (ret < 8)
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        return ret < 0 ? ret : AVERROR_EOF;
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    yop->palette_size       = video_dec->extradata[0] * 3 + 4;
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    yop->audio_block_length = AV_RL16(video_dec->extradata + 6);
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    // 1840 samples per frame, 1 nibble per sample; hence 1840/2 = 920
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    if (yop->audio_block_length < 920 ||
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        yop->audio_block_length + yop->palette_size >= yop->frame_size) {
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        av_log(s, AV_LOG_ERROR, "YOP has invalid header\n");
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        return AVERROR_INVALIDDATA;
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    }
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    avio_seek(pb, 2048, SEEK_SET);
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    av_set_pts_info(video_stream, 32, 1, frame_rate);
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    return 0;
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}
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static int yop_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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    YopDecContext *yop = s->priv_data;
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    AVIOContext *pb  = s->pb;
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    int ret;
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    int actual_video_data_size = yop->frame_size -
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                                 yop->audio_block_length - yop->palette_size;
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    yop->video_packet.stream_index = 1;
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    if (yop->video_packet.data) {
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        *pkt                   =  yop->video_packet;
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        yop->video_packet.data =  NULL;
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        yop->video_packet.size =  0;
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        pkt->data[0]           =  yop->odd_frame;
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        pkt->flags             |= AV_PKT_FLAG_KEY;
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        yop->odd_frame         ^= 1;
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        return pkt->size;
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    }
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    ret = av_new_packet(&yop->video_packet,
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                        yop->frame_size - yop->audio_block_length);
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    if (ret < 0)
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        return ret;
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    yop->video_packet.pos = url_ftell(pb);
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    ret = avio_read(pb, yop->video_packet.data, yop->palette_size);
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    if (ret < 0) {
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        goto err_out;
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    }else if (ret < yop->palette_size) {
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        ret = AVERROR_EOF;
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        goto err_out;
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    }
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    ret = av_get_packet(pb, pkt, 920);
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    if (ret < 0)
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        goto err_out;
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    // Set position to the start of the frame
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    pkt->pos = yop->video_packet.pos;
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    avio_seek(pb, yop->audio_block_length - ret, SEEK_CUR);
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    ret = avio_read(pb, yop->video_packet.data + yop->palette_size,
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                     actual_video_data_size);
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    if (ret < 0)
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        goto err_out;
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    else if (ret < actual_video_data_size)
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        av_shrink_packet(&yop->video_packet, yop->palette_size + ret);
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    // Arbitrarily return the audio data first
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    return yop->audio_block_length;
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err_out:
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    av_free_packet(&yop->video_packet);
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    return ret;
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}
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static int yop_read_close(AVFormatContext *s)
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{
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    YopDecContext *yop = s->priv_data;
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    av_free_packet(&yop->video_packet);
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    return 0;
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}
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static int yop_read_seek(AVFormatContext *s, int stream_index,
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                         int64_t timestamp, int flags)
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{
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    YopDecContext *yop = s->priv_data;
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    int64_t frame_pos, pos_min, pos_max;
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    int frame_count;
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    av_free_packet(&yop->video_packet);
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    if (!stream_index)
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        return -1;
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    pos_min        = s->data_offset;
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    pos_max        = url_fsize(s->pb) - yop->frame_size;
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    frame_count    = (pos_max - pos_min) / yop->frame_size;
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    timestamp      = FFMAX(0, FFMIN(frame_count, timestamp));
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    frame_pos      = timestamp * yop->frame_size + pos_min;
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    yop->odd_frame = timestamp & 1;
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    avio_seek(s->pb, frame_pos, SEEK_SET);
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    return 0;
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}
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AVInputFormat ff_yop_demuxer = {
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    "yop",
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    NULL_IF_CONFIG_SMALL("Psygnosis YOP Format"),
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    sizeof(YopDecContext),
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    yop_probe,
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    yop_read_header,
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    yop_read_packet,
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    yop_read_close,
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    yop_read_seek,
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    .extensions = "yop",
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    .flags = AVFMT_GENERIC_INDEX,
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};