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ffmpeg/libavformat/yop.c

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/*
* Psygnosis YOP demuxer
*
* Copyright (C) 2010 Mohamed Naufal Basheer <naufal11@gmail.com>
* derived from the code by
* Copyright (C) 2009 Thomas P. Higdon <thomas.p.higdon@gmail.com>
*
* 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/channel_layout.h"
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "internal.h"
typedef struct yop_dec_context {
AVPacket video_packet;
int odd_frame;
int frame_size;
int audio_block_length;
int palette_size;
} YopDecContext;
static int yop_probe(AVProbeData *probe_packet)
{
if (AV_RB16(probe_packet->buf) == AV_RB16("YO") &&
probe_packet->buf[6] &&
probe_packet->buf[7] &&
!(probe_packet->buf[8] & 1) &&
!(probe_packet->buf[10] & 1))
return AVPROBE_SCORE_MAX * 3 / 4;
return 0;
}
static int yop_read_header(AVFormatContext *s)
{
YopDecContext *yop = s->priv_data;
AVIOContext *pb = s->pb;
AVCodecContext *audio_dec, *video_dec;
AVStream *audio_stream, *video_stream;
int frame_rate, ret;
audio_stream = avformat_new_stream(s, NULL);
video_stream = avformat_new_stream(s, NULL);
// Extra data that will be passed to the decoder
video_stream->codec->extradata = av_mallocz(8 + AV_INPUT_BUFFER_PADDING_SIZE);
if (!video_stream->codec->extradata)
return AVERROR(ENOMEM);
video_stream->codec->extradata_size = 8;
// Audio
audio_dec = audio_stream->codec;
audio_dec->codec_type = AVMEDIA_TYPE_AUDIO;
audio_dec->codec_id = AV_CODEC_ID_ADPCM_IMA_APC;
audio_dec->channels = 1;
audio_dec->channel_layout = AV_CH_LAYOUT_MONO;
audio_dec->sample_rate = 22050;
// Video
video_dec = video_stream->codec;
video_dec->codec_type = AVMEDIA_TYPE_VIDEO;
video_dec->codec_id = AV_CODEC_ID_YOP;
avio_skip(pb, 6);
frame_rate = avio_r8(pb);
yop->frame_size = avio_r8(pb) * 2048;
video_dec->width = avio_rl16(pb);
video_dec->height = avio_rl16(pb);
video_stream->sample_aspect_ratio = (AVRational){1, 2};
ret = avio_read(pb, video_dec->extradata, 8);
if (ret < 8)
return ret < 0 ? ret : AVERROR_EOF;
yop->palette_size = video_dec->extradata[0] * 3 + 4;
yop->audio_block_length = AV_RL16(video_dec->extradata + 6);
// 1840 samples per frame, 1 nibble per sample; hence 1840/2 = 920
if (yop->audio_block_length < 920 ||
yop->audio_block_length + yop->palette_size >= yop->frame_size) {
av_log(s, AV_LOG_ERROR, "YOP has invalid header\n");
return AVERROR_INVALIDDATA;
}
avio_seek(pb, 2048, SEEK_SET);
avpriv_set_pts_info(video_stream, 32, 1, frame_rate);
return 0;
}
static int yop_read_packet(AVFormatContext *s, AVPacket *pkt)
{
YopDecContext *yop = s->priv_data;
AVIOContext *pb = s->pb;
int ret;
int actual_video_data_size = yop->frame_size -
yop->audio_block_length - yop->palette_size;
yop->video_packet.stream_index = 1;
if (yop->video_packet.data) {
*pkt = yop->video_packet;
yop->video_packet.data = NULL;
yop->video_packet.buf = NULL;
#if FF_API_DESTRUCT_PACKET
FF_DISABLE_DEPRECATION_WARNINGS
yop->video_packet.destruct = NULL;
FF_ENABLE_DEPRECATION_WARNINGS
#endif
yop->video_packet.size = 0;
pkt->data[0] = yop->odd_frame;
pkt->flags |= AV_PKT_FLAG_KEY;
yop->odd_frame ^= 1;
return pkt->size;
}
ret = av_new_packet(&yop->video_packet,
yop->frame_size - yop->audio_block_length);
if (ret < 0)
return ret;
yop->video_packet.pos = avio_tell(pb);
ret = avio_read(pb, yop->video_packet.data, yop->palette_size);
if (ret < 0) {
goto err_out;
}else if (ret < yop->palette_size) {
ret = AVERROR_EOF;
goto err_out;
}
ret = av_get_packet(pb, pkt, 920);
if (ret < 0)
goto err_out;
// Set position to the start of the frame
pkt->pos = yop->video_packet.pos;
avio_skip(pb, yop->audio_block_length - ret);
ret = avio_read(pb, yop->video_packet.data + yop->palette_size,
actual_video_data_size);
if (ret < 0)
goto err_out;
else if (ret < actual_video_data_size)
av_shrink_packet(&yop->video_packet, yop->palette_size + ret);
// Arbitrarily return the audio data first
return yop->audio_block_length;
err_out:
av_free_packet(&yop->video_packet);
return ret;
}
static int yop_read_close(AVFormatContext *s)
{
YopDecContext *yop = s->priv_data;
av_free_packet(&yop->video_packet);
return 0;
}
static int yop_read_seek(AVFormatContext *s, int stream_index,
int64_t timestamp, int flags)
{
YopDecContext *yop = s->priv_data;
int64_t frame_pos, pos_min, pos_max;
int frame_count;
if (!stream_index)
return -1;
pos_min = s->internal->data_offset;
pos_max = avio_size(s->pb) - yop->frame_size;
frame_count = (pos_max - pos_min) / yop->frame_size;
timestamp = FFMAX(0, FFMIN(frame_count, timestamp));
frame_pos = timestamp * yop->frame_size + pos_min;
if (avio_seek(s->pb, frame_pos, SEEK_SET) < 0)
return -1;
av_free_packet(&yop->video_packet);
yop->odd_frame = timestamp & 1;
return 0;
}
AVInputFormat ff_yop_demuxer = {
.name = "yop",
.long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP"),
.priv_data_size = sizeof(YopDecContext),
.read_probe = yop_probe,
.read_header = yop_read_header,
.read_packet = yop_read_packet,
.read_close = yop_read_close,
.read_seek = yop_read_seek,
.extensions = "yop",
.flags = AVFMT_GENERIC_INDEX,
};
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