Implement YOP demuxer and video decoder.
[libav.git] / libavformat / yop.c
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148bcae9
MN
1/**
2 * @file libavformat/yop.c
3 * Psygnosis YOP demuxer
4 *
5 * Copyright (C) 2010 Mohamed Naufal Basheer <naufal11@gmail.com>
6 * derived from the code by
7 * Copyright (C) 2009 Thomas P. Higdon <thomas.p.higdon@gmail.com>
8 *
9 * This file is part of FFmpeg.
10 *
11 * FFmpeg is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU Lesser General Public
13 * License as published by the Free Software Foundation; either
14 * version 2.1 of the License, or (at your option) any later version.
15 *
16 * FFmpeg is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with FFmpeg; if not, write to the Free Software
23 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 */
25
26#include "libavutil/intreadwrite.h"
27#include "avformat.h"
28
29typedef struct yop_dec_context {
30 AVPacket video_packet;
31
32 int odd_frame;
33 int frame_size;
34 int audio_block_length;
35 int palette_size;
36} YopDecContext;
37
38static int yop_probe(AVProbeData *probe_packet)
39{
40 if (AV_RB16(probe_packet->buf) == AV_RB16("YO") &&
41 probe_packet->buf[6] &&
42 probe_packet->buf[7] &&
43 !(probe_packet->buf[8] & 1) &&
44 !(probe_packet->buf[10] & 1))
45 return AVPROBE_SCORE_MAX * 3 / 4;
46
47 return 0;
48}
49
50static int yop_read_header(AVFormatContext *s, AVFormatParameters *ap)
51{
52 YopDecContext *yop = s->priv_data;
53 ByteIOContext *pb = s->pb;
54
55 AVCodecContext *audio_dec, *video_dec;
56 AVStream *audio_stream, *video_stream;
57
58 int frame_rate, ret;
59
60 audio_stream = av_new_stream(s, 0);
61 video_stream = av_new_stream(s, 1);
62
63 // Extra data that will be passed to the decoder
64 video_stream->codec->extradata_size = 8;
65
66 video_stream->codec->extradata = av_mallocz(video_stream->codec->extradata_size +
67 FF_INPUT_BUFFER_PADDING_SIZE);
68
69 if (!video_stream->codec->extradata)
70 return AVERROR(ENOMEM);
71
72 // Audio
73 audio_dec = audio_stream->codec;
74 audio_dec->codec_type = CODEC_TYPE_AUDIO;
75 audio_dec->codec_id = CODEC_ID_ADPCM_IMA_WS;
76 audio_dec->channels = 1;
77 audio_dec->sample_rate = 22050;
78
79 // Video
80 video_dec = video_stream->codec;
81 video_dec->codec_type = CODEC_TYPE_VIDEO;
82 video_dec->codec_id = CODEC_ID_YOP;
83
84 url_fskip(pb, 6);
85
86 frame_rate = get_byte(pb);
87 yop->frame_size = get_byte(pb) * 2048;
88 video_dec->width = get_le16(pb);
89 video_dec->height = get_le16(pb);
90
91 video_stream->sample_aspect_ratio = (AVRational){1, 2};
92
93 ret = get_buffer(pb, video_dec->extradata, 8);
94 if (ret < 8)
95 return ret < 0 ? ret : AVERROR_EOF;
96
97 yop->palette_size = video_dec->extradata[0] * 3 + 4;
98 yop->audio_block_length = AV_RL16(video_dec->extradata + 6);
99
100 // 1840 samples per frame, 1 nibble per sample; hence 1840/2 = 920
101 if (yop->audio_block_length < 920 ||
102 yop->audio_block_length + yop->palette_size >= yop->frame_size) {
103 av_log(s, AV_LOG_ERROR, "YOP has invalid header\n");
104 return AVERROR_INVALIDDATA;
105 }
106
107 url_fseek(pb, 2048, SEEK_SET);
108
109 av_set_pts_info(video_stream, 32, 1, frame_rate);
110
111 return 0;
112}
113
114static int yop_read_packet(AVFormatContext *s, AVPacket *pkt)
115{
116 YopDecContext *yop = s->priv_data;
117 ByteIOContext *pb = s->pb;
118
119 int ret;
120 int actual_video_data_size = yop->frame_size -
121 yop->audio_block_length - yop->palette_size;
122
123 yop->video_packet.stream_index = 1;
124
125 if (yop->video_packet.data) {
126 *pkt = yop->video_packet;
127 yop->video_packet.data = NULL;
128 yop->video_packet.size = 0;
129 pkt->data[0] = yop->odd_frame;
130 pkt->flags |= PKT_FLAG_KEY;
131 yop->odd_frame ^= 1;
132 return pkt->size;
133 }
134 ret = av_new_packet(&yop->video_packet,
135 yop->frame_size - yop->audio_block_length);
136 if (ret < 0)
137 return ret;
138
139 yop->video_packet.pos = url_ftell(pb);
140
141 ret = get_buffer(pb, yop->video_packet.data, yop->palette_size);
142 if (ret < 0) {
143 goto err_out;
144 }else if (ret < yop->palette_size) {
145 ret = AVERROR_EOF;
146 goto err_out;
147 }
148
149 ret = av_get_packet(pb, pkt, 920);
150 if (ret < 0)
151 goto err_out;
152
153 // Set position to the start of the frame
154 pkt->pos = yop->video_packet.pos;
155
156 url_fskip(pb, yop->audio_block_length - ret);
157
158 ret = get_buffer(pb, yop->video_packet.data + yop->palette_size,
159 actual_video_data_size);
160 if (ret < 0)
161 goto err_out;
162 else if (ret < actual_video_data_size)
163 av_shrink_packet(&yop->video_packet, yop->palette_size + ret);
164
165 // Arbitrarily return the audio data first
166 return yop->audio_block_length;
167
168err_out:
169 av_free_packet(&yop->video_packet);
170 return ret;
171}
172
173static int yop_read_close(AVFormatContext *s)
174{
175 YopDecContext *yop = s->priv_data;
176 av_free_packet(&yop->video_packet);
177 return 0;
178}
179
180static int yop_read_seek(AVFormatContext *s, int stream_index,
181 int64_t timestamp, int flags)
182{
183 YopDecContext *yop = s->priv_data;
184 int64_t frame_pos, pos_min, pos_max;
185 int frame_count;
186
187 av_free_packet(&yop->video_packet);
188
189 if (!stream_index)
190 return -1;
191
192 pos_min = s->data_offset;
193 pos_max = url_fsize(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 yop->odd_frame = timestamp & 1;
200
201 url_fseek(s->pb, frame_pos, SEEK_SET);
202 return 0;
203}
204
205AVInputFormat yop_demuxer = {
206 "yop",
207 NULL_IF_CONFIG_SMALL("Psygnosis YOP Format"),
208 sizeof(YopDecContext),
209 yop_probe,
210 yop_read_header,
211 yop_read_packet,
212 yop_read_close,
213 yop_read_seek,
214 .extensions = "yop",
215 .flags = AVFMT_GENERIC_INDEX,
216};