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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  video_stream->codec->extradata_size = 8;
73 
74  video_stream->codec->extradata = av_mallocz(video_stream->codec->extradata_size +
76 
77  if (!video_stream->codec->extradata)
78  return AVERROR(ENOMEM);
79 
80  // Audio
81  audio_dec = audio_stream->codec;
82  audio_dec->codec_type = AVMEDIA_TYPE_AUDIO;
84  audio_dec->channels = 1;
85  audio_dec->channel_layout = AV_CH_LAYOUT_MONO;
86  audio_dec->sample_rate = 22050;
87 
88  // Video
89  video_dec = video_stream->codec;
90  video_dec->codec_type = AVMEDIA_TYPE_VIDEO;
91  video_dec->codec_id = AV_CODEC_ID_YOP;
92 
93  avio_skip(pb, 6);
94 
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);
99 
100  video_stream->sample_aspect_ratio = (AVRational){1, 2};
101 
102  ret = avio_read(pb, video_dec->extradata, 8);
103  if (ret < 8)
104  return ret < 0 ? ret : AVERROR_EOF;
105 
106  yop->palette_size = video_dec->extradata[0] * 3 + 4;
107  yop->audio_block_length = AV_RL16(video_dec->extradata + 6);
108 
109  video_dec->bit_rate = 8 * (yop->frame_size - yop->audio_block_length) * frame_rate;
110 
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;
116  }
117 
118  avio_seek(pb, 2048, SEEK_SET);
119 
120  avpriv_set_pts_info(video_stream, 32, 1, frame_rate);
121 
122  return 0;
123 }
124 
126 {
127  YopDecContext *yop = s->priv_data;
128  AVIOContext *pb = s->pb;
129 
130  int ret;
131  int actual_video_data_size = yop->frame_size -
132  yop->audio_block_length - yop->palette_size;
133 
134  yop->video_packet.stream_index = 1;
135 
136  if (yop->video_packet.data) {
137  *pkt = yop->video_packet;
138  memset(&yop->video_packet, 0, sizeof(yop->video_packet));
139  pkt->data[0] = yop->odd_frame;
140  pkt->flags |= AV_PKT_FLAG_KEY;
141  yop->odd_frame ^= 1;
142  return pkt->size;
143  }
144  ret = av_new_packet(&yop->video_packet,
145  yop->frame_size - yop->audio_block_length);
146  if (ret < 0)
147  return ret;
148 
149  yop->video_packet.pos = avio_tell(pb);
150 
151  ret = avio_read(pb, yop->video_packet.data, yop->palette_size);
152  if (ret < 0) {
153  goto err_out;
154  }else if (ret < yop->palette_size) {
155  ret = AVERROR_EOF;
156  goto err_out;
157  }
158 
159  ret = av_get_packet(pb, pkt, 920);
160  if (ret < 0)
161  goto err_out;
162 
163  // Set position to the start of the frame
164  pkt->pos = yop->video_packet.pos;
165 
166  avio_skip(pb, yop->audio_block_length - ret);
167 
168  ret = avio_read(pb, yop->video_packet.data + yop->palette_size,
169  actual_video_data_size);
170  if (ret < 0)
171  goto err_out;
172  else if (ret < actual_video_data_size)
173  av_shrink_packet(&yop->video_packet, yop->palette_size + ret);
174 
175  // Arbitrarily return the audio data first
176  return yop->audio_block_length;
177 
178 err_out:
180  return ret;
181 }
182 
184 {
185  YopDecContext *yop = s->priv_data;
187  return 0;
188 }
189 
190 static int yop_read_seek(AVFormatContext *s, int stream_index,
191  int64_t timestamp, int flags)
192 {
193  YopDecContext *yop = s->priv_data;
194  int64_t frame_pos, pos_min, pos_max;
195  int frame_count;
196 
197  if (!stream_index)
198  return -1;
199 
200  pos_min = s->data_offset;
201  pos_max = avio_size(s->pb) - yop->frame_size;
202  frame_count = (pos_max - pos_min) / yop->frame_size;
203 
204  timestamp = FFMAX(0, FFMIN(frame_count, timestamp));
205 
206  frame_pos = timestamp * yop->frame_size + pos_min;
207 
208  if (avio_seek(s->pb, frame_pos, SEEK_SET) < 0)
209  return -1;
210 
212  yop->odd_frame = timestamp & 1;
213 
214  return 0;
215 }
216 
218  .name = "yop",
219  .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP"),
220  .priv_data_size = sizeof(YopDecContext),
226  .extensions = "yop",
228 };