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 Libav.
9  *
10  * Libav 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  * Libav 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 Libav; 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[6] &&
43  probe_packet->buf[7] &&
44  !(probe_packet->buf[8] & 1) &&
45  !(probe_packet->buf[10] & 1))
46  return AVPROBE_SCORE_MAX * 3 / 4;
47 
48  return 0;
49 }
50 
52 {
53  YopDecContext *yop = s->priv_data;
54  AVIOContext *pb = s->pb;
55 
56  AVCodecContext *audio_dec, *video_dec;
57  AVStream *audio_stream, *video_stream;
58 
59  int frame_rate, ret;
60 
61  audio_stream = avformat_new_stream(s, NULL);
62  video_stream = avformat_new_stream(s, NULL);
63 
64  // Extra data that will be passed to the decoder
65  video_stream->codec->extradata_size = 8;
66 
67  video_stream->codec->extradata = av_mallocz(video_stream->codec->extradata_size +
69 
70  if (!video_stream->codec->extradata)
71  return AVERROR(ENOMEM);
72 
73  // Audio
74  audio_dec = audio_stream->codec;
75  audio_dec->codec_type = AVMEDIA_TYPE_AUDIO;
77  audio_dec->channels = 1;
78  audio_dec->channel_layout = AV_CH_LAYOUT_MONO;
79  audio_dec->sample_rate = 22050;
80 
81  // Video
82  video_dec = video_stream->codec;
83  video_dec->codec_type = AVMEDIA_TYPE_VIDEO;
84  video_dec->codec_id = AV_CODEC_ID_YOP;
85 
86  avio_skip(pb, 6);
87 
88  frame_rate = avio_r8(pb);
89  yop->frame_size = avio_r8(pb) * 2048;
90  video_dec->width = avio_rl16(pb);
91  video_dec->height = avio_rl16(pb);
92 
93  video_stream->sample_aspect_ratio = (AVRational){1, 2};
94 
95  ret = avio_read(pb, video_dec->extradata, 8);
96  if (ret < 8)
97  return ret < 0 ? ret : AVERROR_EOF;
98 
99  yop->palette_size = video_dec->extradata[0] * 3 + 4;
100  yop->audio_block_length = AV_RL16(video_dec->extradata + 6);
101 
102  // 1840 samples per frame, 1 nibble per sample; hence 1840/2 = 920
103  if (yop->audio_block_length < 920 ||
104  yop->audio_block_length + yop->palette_size >= yop->frame_size) {
105  av_log(s, AV_LOG_ERROR, "YOP has invalid header\n");
106  return AVERROR_INVALIDDATA;
107  }
108 
109  avio_seek(pb, 2048, SEEK_SET);
110 
111  avpriv_set_pts_info(video_stream, 32, 1, frame_rate);
112 
113  return 0;
114 }
115 
117 {
118  YopDecContext *yop = s->priv_data;
119  AVIOContext *pb = s->pb;
120 
121  int ret;
122  int actual_video_data_size = yop->frame_size -
123  yop->audio_block_length - yop->palette_size;
124 
125  yop->video_packet.stream_index = 1;
126 
127  if (yop->video_packet.data) {
128  *pkt = yop->video_packet;
129  yop->video_packet.data = NULL;
130  yop->video_packet.size = 0;
131  pkt->data[0] = yop->odd_frame;
132  pkt->flags |= AV_PKT_FLAG_KEY;
133  yop->odd_frame ^= 1;
134  return pkt->size;
135  }
136  ret = av_new_packet(&yop->video_packet,
137  yop->frame_size - yop->audio_block_length);
138  if (ret < 0)
139  return ret;
140 
141  yop->video_packet.pos = avio_tell(pb);
142 
143  ret = avio_read(pb, yop->video_packet.data, yop->palette_size);
144  if (ret < 0) {
145  goto err_out;
146  }else if (ret < yop->palette_size) {
147  ret = AVERROR_EOF;
148  goto err_out;
149  }
150 
151  ret = av_get_packet(pb, pkt, 920);
152  if (ret < 0)
153  goto err_out;
154 
155  // Set position to the start of the frame
156  pkt->pos = yop->video_packet.pos;
157 
158  avio_skip(pb, yop->audio_block_length - ret);
159 
160  ret = avio_read(pb, yop->video_packet.data + yop->palette_size,
161  actual_video_data_size);
162  if (ret < 0)
163  goto err_out;
164  else if (ret < actual_video_data_size)
165  av_shrink_packet(&yop->video_packet, yop->palette_size + ret);
166 
167  // Arbitrarily return the audio data first
168  return yop->audio_block_length;
169 
170 err_out:
171  av_free_packet(&yop->video_packet);
172  return ret;
173 }
174 
176 {
177  YopDecContext *yop = s->priv_data;
178  av_free_packet(&yop->video_packet);
179  return 0;
180 }
181 
182 static int yop_read_seek(AVFormatContext *s, int stream_index,
183  int64_t timestamp, int flags)
184 {
185  YopDecContext *yop = s->priv_data;
186  int64_t frame_pos, pos_min, pos_max;
187  int frame_count;
188 
189  if (!stream_index)
190  return -1;
191 
192  pos_min = s->data_offset;
193  pos_max = avio_size(s->pb) - yop->frame_size;
194  frame_count = (pos_max - pos_min) / yop->frame_size;
195 
196  timestamp = FFMAX(0, FFMIN(frame_count, timestamp));
197 
198  frame_pos = timestamp * yop->frame_size + pos_min;
199 
200  if (avio_seek(s->pb, frame_pos, SEEK_SET) < 0)
201  return -1;
202 
203  av_free_packet(&yop->video_packet);
204  yop->odd_frame = timestamp & 1;
205 
206  return 0;
207 }
208 
210  .name = "yop",
211  .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP"),
212  .priv_data_size = sizeof(YopDecContext),
218  .extensions = "yop",
220 };