tls: Hide backend implementation details from users
[libav.git] / libavformat / yop.c
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
25 #include "libavutil/channel_layout.h"
26 #include "libavutil/intreadwrite.h"
27 #include "avformat.h"
28 #include "internal.h"
29
30 typedef 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
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
51 static int yop_read_header(AVFormatContext *s)
52 {
53 YopDecContext *yop = s->priv_data;
54 AVIOContext *pb = s->pb;
55
56 AVCodecParameters *audio_par, *video_par;
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
66 video_stream->codecpar->extradata = av_mallocz(8 + AV_INPUT_BUFFER_PADDING_SIZE);
67
68 if (!video_stream->codecpar->extradata)
69 return AVERROR(ENOMEM);
70 video_stream->codecpar->extradata_size = 8;
71
72 // Audio
73 audio_par = audio_stream->codecpar;
74 audio_par->codec_type = AVMEDIA_TYPE_AUDIO;
75 audio_par->codec_id = AV_CODEC_ID_ADPCM_IMA_APC;
76 audio_par->channels = 1;
77 audio_par->channel_layout = AV_CH_LAYOUT_MONO;
78 audio_par->sample_rate = 22050;
79
80 // Video
81 video_par = video_stream->codecpar;
82 video_par->codec_type = AVMEDIA_TYPE_VIDEO;
83 video_par->codec_id = AV_CODEC_ID_YOP;
84
85 avio_skip(pb, 6);
86
87 frame_rate = avio_r8(pb);
88 yop->frame_size = avio_r8(pb) * 2048;
89 video_par->width = avio_rl16(pb);
90 video_par->height = avio_rl16(pb);
91
92 video_stream->sample_aspect_ratio = (AVRational){1, 2};
93
94 ret = avio_read(pb, video_par->extradata, 8);
95 if (ret < 8)
96 return ret < 0 ? ret : AVERROR_EOF;
97
98 yop->palette_size = video_par->extradata[0] * 3 + 4;
99 yop->audio_block_length = AV_RL16(video_par->extradata + 6);
100
101 // 1840 samples per frame, 1 nibble per sample; hence 1840/2 = 920
102 if (yop->audio_block_length < 920 ||
103 yop->audio_block_length + yop->palette_size >= yop->frame_size) {
104 av_log(s, AV_LOG_ERROR, "YOP has invalid header\n");
105 return AVERROR_INVALIDDATA;
106 }
107
108 avio_seek(pb, 2048, SEEK_SET);
109
110 avpriv_set_pts_info(video_stream, 32, 1, frame_rate);
111
112 return 0;
113 }
114
115 static int yop_read_packet(AVFormatContext *s, AVPacket *pkt)
116 {
117 YopDecContext *yop = s->priv_data;
118 AVIOContext *pb = s->pb;
119
120 int ret;
121 int actual_video_data_size = yop->frame_size -
122 yop->audio_block_length - yop->palette_size;
123
124 yop->video_packet.stream_index = 1;
125
126 if (yop->video_packet.data) {
127 *pkt = yop->video_packet;
128 yop->video_packet.data = NULL;
129 yop->video_packet.buf = 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_packet_unref(&yop->video_packet);
172 return ret;
173 }
174
175 static int yop_read_close(AVFormatContext *s)
176 {
177 YopDecContext *yop = s->priv_data;
178 av_packet_unref(&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->internal->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_packet_unref(&yop->video_packet);
204 yop->odd_frame = timestamp & 1;
205
206 return 0;
207 }
208
209 AVInputFormat ff_yop_demuxer = {
210 .name = "yop",
211 .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP"),
212 .priv_data_size = sizeof(YopDecContext),
213 .read_probe = yop_probe,
214 .read_header = yop_read_header,
215 .read_packet = yop_read_packet,
216 .read_close = yop_read_close,
217 .read_seek = yop_read_seek,
218 .extensions = "yop",
219 .flags = AVFMT_GENERIC_INDEX,
220 };