2 * Psygnosis YOP demuxer
4 * Copyright (C) 2010 Mohamed Naufal Basheer <naufal11@gmail.com>
5 * derived from the code by
6 * Copyright (C) 2009 Thomas P. Higdon <thomas.p.higdon@gmail.com>
8 * This file is part of FFmpeg.
10 * FFmpeg is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
15 * FFmpeg is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * Lesser General Public License for more details.
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with FFmpeg; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 #include "libavutil/channel_layout.h"
26 #include "libavutil/intreadwrite.h"
30 typedef struct yop_dec_context {
31 AVPacket video_packet;
35 int audio_block_length;
39 static int yop_probe(AVProbeData *probe_packet)
41 if (AV_RB16(probe_packet->buf) == AV_RB16("YO") &&
42 probe_packet->buf[2]<10 &&
43 probe_packet->buf[3]<10 &&
44 probe_packet->buf[6] &&
45 probe_packet->buf[7] &&
46 !(probe_packet->buf[8] & 1) &&
47 !(probe_packet->buf[10] & 1) &&
48 AV_RL16(probe_packet->buf + 12 + 6) >= 920 &&
49 AV_RL16(probe_packet->buf + 12 + 6) < probe_packet->buf[12] * 3 + 4 + probe_packet->buf[7] * 2048
51 return AVPROBE_SCORE_MAX * 3 / 4;
56 static int yop_read_header(AVFormatContext *s)
58 YopDecContext *yop = s->priv_data;
59 AVIOContext *pb = s->pb;
61 AVCodecContext *audio_dec, *video_dec;
62 AVStream *audio_stream, *video_stream;
66 audio_stream = avformat_new_stream(s, NULL);
67 video_stream = avformat_new_stream(s, NULL);
68 if (!audio_stream || !video_stream)
69 return AVERROR(ENOMEM);
71 // Extra data that will be passed to the decoder
72 video_stream->codec->extradata_size = 8;
74 video_stream->codec->extradata = av_mallocz(video_stream->codec->extradata_size +
75 FF_INPUT_BUFFER_PADDING_SIZE);
77 if (!video_stream->codec->extradata)
78 return AVERROR(ENOMEM);
81 audio_dec = audio_stream->codec;
82 audio_dec->codec_type = AVMEDIA_TYPE_AUDIO;
83 audio_dec->codec_id = AV_CODEC_ID_ADPCM_IMA_APC;
84 audio_dec->channels = 1;
85 audio_dec->channel_layout = AV_CH_LAYOUT_MONO;
86 audio_dec->sample_rate = 22050;
89 video_dec = video_stream->codec;
90 video_dec->codec_type = AVMEDIA_TYPE_VIDEO;
91 video_dec->codec_id = AV_CODEC_ID_YOP;
95 frame_rate = avio_r8(pb);
96 yop->frame_size = avio_r8(pb) * 2048;
97 video_dec->width = avio_rl16(pb);
98 video_dec->height = avio_rl16(pb);
100 video_stream->sample_aspect_ratio = (AVRational){1, 2};
102 ret = avio_read(pb, video_dec->extradata, 8);
104 return ret < 0 ? ret : AVERROR_EOF;
106 yop->palette_size = video_dec->extradata[0] * 3 + 4;
107 yop->audio_block_length = AV_RL16(video_dec->extradata + 6);
109 video_dec->bit_rate = 8 * (yop->frame_size - yop->audio_block_length) * frame_rate;
111 // 1840 samples per frame, 1 nibble per sample; hence 1840/2 = 920
112 if (yop->audio_block_length < 920 ||
113 yop->audio_block_length + yop->palette_size >= yop->frame_size) {
114 av_log(s, AV_LOG_ERROR, "YOP has invalid header\n");
115 return AVERROR_INVALIDDATA;
118 avio_seek(pb, 2048, SEEK_SET);
120 avpriv_set_pts_info(video_stream, 32, 1, frame_rate);
125 static int yop_read_packet(AVFormatContext *s, AVPacket *pkt)
127 YopDecContext *yop = s->priv_data;
128 AVIOContext *pb = s->pb;
131 int actual_video_data_size = yop->frame_size -
132 yop->audio_block_length - yop->palette_size;
134 yop->video_packet.stream_index = 1;
136 if (yop->video_packet.data) {
137 *pkt = yop->video_packet;
138 yop->video_packet.data = NULL;
139 yop->video_packet.size = 0;
140 pkt->data[0] = yop->odd_frame;
141 pkt->flags |= AV_PKT_FLAG_KEY;
145 ret = av_new_packet(&yop->video_packet,
146 yop->frame_size - yop->audio_block_length);
150 yop->video_packet.pos = avio_tell(pb);
152 ret = avio_read(pb, yop->video_packet.data, yop->palette_size);
155 }else if (ret < yop->palette_size) {
160 ret = av_get_packet(pb, pkt, 920);
164 // Set position to the start of the frame
165 pkt->pos = yop->video_packet.pos;
167 avio_skip(pb, yop->audio_block_length - ret);
169 ret = avio_read(pb, yop->video_packet.data + yop->palette_size,
170 actual_video_data_size);
173 else if (ret < actual_video_data_size)
174 av_shrink_packet(&yop->video_packet, yop->palette_size + ret);
176 // Arbitrarily return the audio data first
177 return yop->audio_block_length;
180 av_free_packet(&yop->video_packet);
184 static int yop_read_close(AVFormatContext *s)
186 YopDecContext *yop = s->priv_data;
187 av_free_packet(&yop->video_packet);
191 static int yop_read_seek(AVFormatContext *s, int stream_index,
192 int64_t timestamp, int flags)
194 YopDecContext *yop = s->priv_data;
195 int64_t frame_pos, pos_min, pos_max;
201 pos_min = s->data_offset;
202 pos_max = avio_size(s->pb) - yop->frame_size;
203 frame_count = (pos_max - pos_min) / yop->frame_size;
205 timestamp = FFMAX(0, FFMIN(frame_count, timestamp));
207 frame_pos = timestamp * yop->frame_size + pos_min;
209 if (avio_seek(s->pb, frame_pos, SEEK_SET) < 0)
212 av_free_packet(&yop->video_packet);
213 yop->odd_frame = timestamp & 1;
218 AVInputFormat ff_yop_demuxer = {
220 .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP"),
221 .priv_data_size = sizeof(YopDecContext),
222 .read_probe = yop_probe,
223 .read_header = yop_read_header,
224 .read_packet = yop_read_packet,
225 .read_close = yop_read_close,
226 .read_seek = yop_read_seek,
228 .flags = AVFMT_GENERIC_INDEX,