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/intreadwrite.h"
29 typedef struct yop_dec_context {
30 AVPacket video_packet;
34 int audio_block_length;
38 static int yop_probe(AVProbeData *probe_packet)
40 if (AV_RB16(probe_packet->buf) == AV_RB16("YO") &&
41 probe_packet->buf[2]<10 &&
42 probe_packet->buf[3]<10 &&
43 probe_packet->buf[6] &&
44 probe_packet->buf[7] &&
45 !(probe_packet->buf[8] & 1) &&
46 !(probe_packet->buf[10] & 1) &&
47 AV_RL16(probe_packet->buf + 12 + 6) >= 920 &&
48 AV_RL16(probe_packet->buf + 12 + 6) < probe_packet->buf[12] * 3 + 4 + probe_packet->buf[7] * 2048
50 return AVPROBE_SCORE_MAX * 3 / 4;
55 static int yop_read_header(AVFormatContext *s)
57 YopDecContext *yop = s->priv_data;
58 AVIOContext *pb = s->pb;
60 AVCodecContext *audio_dec, *video_dec;
61 AVStream *audio_stream, *video_stream;
65 audio_stream = avformat_new_stream(s, NULL);
66 video_stream = avformat_new_stream(s, NULL);
67 if (!audio_stream || !video_stream)
68 return AVERROR(ENOMEM);
70 // Extra data that will be passed to the decoder
71 video_stream->codec->extradata_size = 8;
73 video_stream->codec->extradata = av_mallocz(video_stream->codec->extradata_size +
74 FF_INPUT_BUFFER_PADDING_SIZE);
76 if (!video_stream->codec->extradata)
77 return AVERROR(ENOMEM);
80 audio_dec = audio_stream->codec;
81 audio_dec->codec_type = AVMEDIA_TYPE_AUDIO;
82 audio_dec->codec_id = AV_CODEC_ID_ADPCM_IMA_APC;
83 audio_dec->channels = 1;
84 audio_dec->sample_rate = 22050;
87 video_dec = video_stream->codec;
88 video_dec->codec_type = AVMEDIA_TYPE_VIDEO;
89 video_dec->codec_id = AV_CODEC_ID_YOP;
93 frame_rate = avio_r8(pb);
94 yop->frame_size = avio_r8(pb) * 2048;
95 video_dec->width = avio_rl16(pb);
96 video_dec->height = avio_rl16(pb);
98 video_stream->sample_aspect_ratio = (AVRational){1, 2};
100 ret = avio_read(pb, video_dec->extradata, 8);
102 return ret < 0 ? ret : AVERROR_EOF;
104 yop->palette_size = video_dec->extradata[0] * 3 + 4;
105 yop->audio_block_length = AV_RL16(video_dec->extradata + 6);
107 // 1840 samples per frame, 1 nibble per sample; hence 1840/2 = 920
108 if (yop->audio_block_length < 920 ||
109 yop->audio_block_length + yop->palette_size >= yop->frame_size) {
110 av_log(s, AV_LOG_ERROR, "YOP has invalid header\n");
111 return AVERROR_INVALIDDATA;
114 avio_seek(pb, 2048, SEEK_SET);
116 avpriv_set_pts_info(video_stream, 32, 1, frame_rate);
121 static int yop_read_packet(AVFormatContext *s, AVPacket *pkt)
123 YopDecContext *yop = s->priv_data;
124 AVIOContext *pb = s->pb;
127 int actual_video_data_size = yop->frame_size -
128 yop->audio_block_length - yop->palette_size;
130 yop->video_packet.stream_index = 1;
132 if (yop->video_packet.data) {
133 *pkt = yop->video_packet;
134 yop->video_packet.data = NULL;
135 yop->video_packet.size = 0;
136 pkt->data[0] = yop->odd_frame;
137 pkt->flags |= AV_PKT_FLAG_KEY;
141 ret = av_new_packet(&yop->video_packet,
142 yop->frame_size - yop->audio_block_length);
146 yop->video_packet.pos = avio_tell(pb);
148 ret = avio_read(pb, yop->video_packet.data, yop->palette_size);
151 }else if (ret < yop->palette_size) {
156 ret = av_get_packet(pb, pkt, 920);
160 // Set position to the start of the frame
161 pkt->pos = yop->video_packet.pos;
163 avio_skip(pb, yop->audio_block_length - ret);
165 ret = avio_read(pb, yop->video_packet.data + yop->palette_size,
166 actual_video_data_size);
169 else if (ret < actual_video_data_size)
170 av_shrink_packet(&yop->video_packet, yop->palette_size + ret);
172 // Arbitrarily return the audio data first
173 return yop->audio_block_length;
176 av_free_packet(&yop->video_packet);
180 static int yop_read_close(AVFormatContext *s)
182 YopDecContext *yop = s->priv_data;
183 av_free_packet(&yop->video_packet);
187 static int yop_read_seek(AVFormatContext *s, int stream_index,
188 int64_t timestamp, int flags)
190 YopDecContext *yop = s->priv_data;
191 int64_t frame_pos, pos_min, pos_max;
197 pos_min = s->data_offset;
198 pos_max = avio_size(s->pb) - yop->frame_size;
199 frame_count = (pos_max - pos_min) / yop->frame_size;
201 timestamp = FFMAX(0, FFMIN(frame_count, timestamp));
203 frame_pos = timestamp * yop->frame_size + pos_min;
205 if (avio_seek(s->pb, frame_pos, SEEK_SET) < 0)
208 av_free_packet(&yop->video_packet);
209 yop->odd_frame = timestamp & 1;
214 AVInputFormat ff_yop_demuxer = {
216 .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP"),
217 .priv_data_size = sizeof(YopDecContext),
218 .read_probe = yop_probe,
219 .read_header = yop_read_header,
220 .read_packet = yop_read_packet,
221 .read_close = yop_read_close,
222 .read_seek = yop_read_seek,
224 .flags = AVFMT_GENERIC_INDEX,