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yop.c
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1 /*
2  * Psygnosis YOP demuxer
3  *
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>
7  *
8  * This file is part of FFmpeg.
9  *
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.
14  *
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.
19  *
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
23  */
24 
26 #include "libavutil/intreadwrite.h"
27 #include "avformat.h"
28 #include "internal.h"
29 
30 typedef struct yop_dec_context {
32 
33  int odd_frame;
38 
39 static int yop_probe(AVProbeData *probe_packet)
40 {
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
50  )
51  return AVPROBE_SCORE_MAX * 3 / 4;
52 
53  return 0;
54 }
55 
57 {
58  YopDecContext *yop = s->priv_data;
59  AVIOContext *pb = s->pb;
60 
61  AVCodecContext *audio_dec, *video_dec;
63 
64  int frame_rate, ret;
65 
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);
70 
71  // Extra data that will be passed to the decoder
72  if (ff_alloc_extradata(video_stream->codec, 8))
73  return AVERROR(ENOMEM);
74 
75  // Audio
76  audio_dec = audio_stream->codec;
77  audio_dec->codec_type = AVMEDIA_TYPE_AUDIO;
79  audio_dec->channels = 1;
80  audio_dec->channel_layout = AV_CH_LAYOUT_MONO;
81  audio_dec->sample_rate = 22050;
82 
83  // Video
84  video_dec = video_stream->codec;
85  video_dec->codec_type = AVMEDIA_TYPE_VIDEO;
86  video_dec->codec_id = AV_CODEC_ID_YOP;
87 
88  avio_skip(pb, 6);
89 
90  frame_rate = avio_r8(pb);
91  yop->frame_size = avio_r8(pb) * 2048;
92  video_dec->width = avio_rl16(pb);
93  video_dec->height = avio_rl16(pb);
94 
95  video_stream->sample_aspect_ratio = (AVRational){1, 2};
96 
97  ret = avio_read(pb, video_dec->extradata, 8);
98  if (ret < 8)
99  return ret < 0 ? ret : AVERROR_EOF;
100 
101  yop->palette_size = video_dec->extradata[0] * 3 + 4;
102  yop->audio_block_length = AV_RL16(video_dec->extradata + 6);
103 
104  video_dec->bit_rate = 8 * (yop->frame_size - yop->audio_block_length) * frame_rate;
105 
106  // 1840 samples per frame, 1 nibble per sample; hence 1840/2 = 920
107  if (yop->audio_block_length < 920 ||
108  yop->audio_block_length + yop->palette_size >= yop->frame_size) {
109  av_log(s, AV_LOG_ERROR, "YOP has invalid header\n");
110  return AVERROR_INVALIDDATA;
111  }
112 
113  avio_seek(pb, 2048, SEEK_SET);
114 
115  avpriv_set_pts_info(video_stream, 32, 1, frame_rate);
116 
117  return 0;
118 }
119 
121 {
122  YopDecContext *yop = s->priv_data;
123  AVIOContext *pb = s->pb;
124 
125  int ret;
126  int actual_video_data_size = yop->frame_size -
127  yop->audio_block_length - yop->palette_size;
128 
129  yop->video_packet.stream_index = 1;
130 
131  if (yop->video_packet.data) {
132  *pkt = yop->video_packet;
133  yop->video_packet.data = NULL;
134  yop->video_packet.buf = NULL;
135 #if FF_API_DESTRUCT_PACKET
137  yop->video_packet.destruct = NULL;
139 #endif
140  yop->video_packet.size = 0;
141  pkt->data[0] = yop->odd_frame;
142  pkt->flags |= AV_PKT_FLAG_KEY;
143  yop->odd_frame ^= 1;
144  return pkt->size;
145  }
146  ret = av_new_packet(&yop->video_packet,
147  yop->frame_size - yop->audio_block_length);
148  if (ret < 0)
149  return ret;
150 
151  yop->video_packet.pos = avio_tell(pb);
152 
153  ret = avio_read(pb, yop->video_packet.data, yop->palette_size);
154  if (ret < 0) {
155  goto err_out;
156  }else if (ret < yop->palette_size) {
157  ret = AVERROR_EOF;
158  goto err_out;
159  }
160 
161  ret = av_get_packet(pb, pkt, 920);
162  if (ret < 0)
163  goto err_out;
164 
165  // Set position to the start of the frame
166  pkt->pos = yop->video_packet.pos;
167 
168  avio_skip(pb, yop->audio_block_length - ret);
169 
170  ret = avio_read(pb, yop->video_packet.data + yop->palette_size,
171  actual_video_data_size);
172  if (ret < 0)
173  goto err_out;
174  else if (ret < actual_video_data_size)
175  av_shrink_packet(&yop->video_packet, yop->palette_size + ret);
176 
177  // Arbitrarily return the audio data first
178  return yop->audio_block_length;
179 
180 err_out:
182  return ret;
183 }
184 
186 {
187  YopDecContext *yop = s->priv_data;
189  return 0;
190 }
191 
192 static int yop_read_seek(AVFormatContext *s, int stream_index,
193  int64_t timestamp, int flags)
194 {
195  YopDecContext *yop = s->priv_data;
196  int64_t frame_pos, pos_min, pos_max;
197  int frame_count;
198 
199  if (!stream_index)
200  return -1;
201 
202  pos_min = s->data_offset;
203  pos_max = avio_size(s->pb) - yop->frame_size;
204  frame_count = (pos_max - pos_min) / yop->frame_size;
205 
206  timestamp = FFMAX(0, FFMIN(frame_count, timestamp));
207 
208  frame_pos = timestamp * yop->frame_size + pos_min;
209 
210  if (avio_seek(s->pb, frame_pos, SEEK_SET) < 0)
211  return -1;
212 
214  yop->odd_frame = timestamp & 1;
215 
216  return 0;
217 }
218 
220  .name = "yop",
221  .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP"),
222  .priv_data_size = sizeof(YopDecContext),
228  .extensions = "yop",
230 };