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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 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
- */
- #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[2]<10 &&
- probe_packet->buf[3]<10 &&
- probe_packet->buf[6] &&
- probe_packet->buf[7] &&
- !(probe_packet->buf[8] & 1) &&
- !(probe_packet->buf[10] & 1) &&
- AV_RL16(probe_packet->buf + 12 + 6) >= 920 &&
- AV_RL16(probe_packet->buf + 12 + 6) < probe_packet->buf[12] * 3 + 4 + probe_packet->buf[7] * 2048
- )
- 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_size = 8;
- video_stream->codec->extradata = av_mallocz(video_stream->codec->extradata_size +
- FF_INPUT_BUFFER_PADDING_SIZE);
- if (!video_stream->codec->extradata)
- return AVERROR(ENOMEM);
- // 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->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.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->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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