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path: root/libavformat/yop.c (plain)
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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
25#include "libavutil/channel_layout.h"
26#include "libavutil/intreadwrite.h"
27#include "avformat.h"
28#include "internal.h"
29
30typedef struct yop_dec_context {
31 AVPacket video_packet;
32
33 int odd_frame;
34 int frame_size;
35 int audio_block_length;
36 int palette_size;
37} YopDecContext;
38
39static 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
56static int yop_read_header(AVFormatContext *s)
57{
58 YopDecContext *yop = s->priv_data;
59 AVIOContext *pb = s->pb;
60
61 AVCodecParameters *audio_par, *video_par;
62 AVStream *audio_stream, *video_stream;
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->codecpar, 8))
73 return AVERROR(ENOMEM);
74
75 // Audio
76 audio_par = audio_stream->codecpar;
77 audio_par->codec_type = AVMEDIA_TYPE_AUDIO;
78 audio_par->codec_id = AV_CODEC_ID_ADPCM_IMA_APC;
79 audio_par->channels = 1;
80 audio_par->channel_layout = AV_CH_LAYOUT_MONO;
81 audio_par->sample_rate = 22050;
82
83 // Video
84 video_par = video_stream->codecpar;
85 video_par->codec_type = AVMEDIA_TYPE_VIDEO;
86 video_par->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_par->width = avio_rl16(pb);
93 video_par->height = avio_rl16(pb);
94
95 video_stream->sample_aspect_ratio = (AVRational){1, 2};
96
97 ret = avio_read(pb, video_par->extradata, 8);
98 if (ret < 8)
99 return ret < 0 ? ret : AVERROR_EOF;
100
101 yop->palette_size = video_par->extradata[0] * 3 + 4;
102 yop->audio_block_length = AV_RL16(video_par->extradata + 6);
103
104 video_par->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
120static int yop_read_packet(AVFormatContext *s, AVPacket *pkt)
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 yop->video_packet.size = 0;
136 pkt->data[0] = yop->odd_frame;
137 pkt->flags |= AV_PKT_FLAG_KEY;
138 yop->odd_frame ^= 1;
139 return pkt->size;
140 }
141 ret = av_new_packet(&yop->video_packet,
142 yop->frame_size - yop->audio_block_length);
143 if (ret < 0)
144 return ret;
145
146 yop->video_packet.pos = avio_tell(pb);
147
148 ret = avio_read(pb, yop->video_packet.data, yop->palette_size);
149 if (ret < 0) {
150 goto err_out;
151 }else if (ret < yop->palette_size) {
152 ret = AVERROR_EOF;
153 goto err_out;
154 }
155
156 ret = av_get_packet(pb, pkt, 920);
157 if (ret < 0)
158 goto err_out;
159
160 // Set position to the start of the frame
161 pkt->pos = yop->video_packet.pos;
162
163 avio_skip(pb, yop->audio_block_length - ret);
164
165 ret = avio_read(pb, yop->video_packet.data + yop->palette_size,
166 actual_video_data_size);
167 if (ret < 0)
168 goto err_out;
169 else if (ret < actual_video_data_size)
170 av_shrink_packet(&yop->video_packet, yop->palette_size + ret);
171
172 // Arbitrarily return the audio data first
173 return yop->audio_block_length;
174
175err_out:
176 av_packet_unref(&yop->video_packet);
177 return ret;
178}
179
180static int yop_read_close(AVFormatContext *s)
181{
182 YopDecContext *yop = s->priv_data;
183 av_packet_unref(&yop->video_packet);
184 return 0;
185}
186
187static int yop_read_seek(AVFormatContext *s, int stream_index,
188 int64_t timestamp, int flags)
189{
190 YopDecContext *yop = s->priv_data;
191 int64_t frame_pos, pos_min, pos_max;
192 int frame_count;
193
194 if (!stream_index)
195 return -1;
196
197 pos_min = s->internal->data_offset;
198 pos_max = avio_size(s->pb) - yop->frame_size;
199 frame_count = (pos_max - pos_min) / yop->frame_size;
200
201 timestamp = FFMAX(0, FFMIN(frame_count, timestamp));
202
203 frame_pos = timestamp * yop->frame_size + pos_min;
204
205 if (avio_seek(s->pb, frame_pos, SEEK_SET) < 0)
206 return -1;
207
208 av_packet_unref(&yop->video_packet);
209 yop->odd_frame = timestamp & 1;
210
211 return 0;
212}
213
214AVInputFormat ff_yop_demuxer = {
215 .name = "yop",
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,
223 .extensions = "yop",
224 .flags = AVFMT_GENERIC_INDEX,
225};
226
generated by cgit at 2024-05-17 06:08:21 (GMT)