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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 
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 
yop_probe(const AVProbeData * probe_packet)39 static int yop_probe(const 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 
yop_read_header(AVFormatContext * s)56 static 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     // Audio
72     audio_par                 = audio_stream->codecpar;
73     audio_par->codec_type     = AVMEDIA_TYPE_AUDIO;
74     audio_par->codec_id       = AV_CODEC_ID_ADPCM_IMA_APC;
75     audio_par->channels       = 1;
76     audio_par->channel_layout = AV_CH_LAYOUT_MONO;
77     audio_par->sample_rate    = 22050;
78 
79     // Video
80     video_par               = video_stream->codecpar;
81     video_par->codec_type   = AVMEDIA_TYPE_VIDEO;
82     video_par->codec_id     = AV_CODEC_ID_YOP;
83 
84     avio_skip(pb, 6);
85 
86     frame_rate              = avio_r8(pb);
87     yop->frame_size         = avio_r8(pb) * 2048;
88     video_par->width        = avio_rl16(pb);
89     video_par->height       = avio_rl16(pb);
90 
91     video_stream->sample_aspect_ratio = (AVRational){1, 2};
92 
93     ret = ff_get_extradata(s, video_par, pb, 8);
94     if (ret < 0)
95         return ret;
96 
97     yop->palette_size       = video_par->extradata[0] * 3 + 4;
98     yop->audio_block_length = AV_RL16(video_par->extradata + 6);
99 
100     video_par->bit_rate     = 8 * (yop->frame_size - yop->audio_block_length) * frame_rate;
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 
yop_read_packet(AVFormatContext * s,AVPacket * pkt)116 static int yop_read_packet(AVFormatContext *s, AVPacket *pkt)
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         av_packet_move_ref(pkt, &yop->video_packet);
129         pkt->data[0]           =  yop->odd_frame;
130         pkt->flags             |= AV_PKT_FLAG_KEY;
131         yop->odd_frame         ^= 1;
132         return 0;
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 = avio_tell(pb);
140 
141     ret = avio_read(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     avio_skip(pb, yop->audio_block_length - ret);
157 
158     ret = avio_read(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 0;
167 
168 err_out:
169     av_packet_unref(&yop->video_packet);
170     return ret;
171 }
172 
yop_read_close(AVFormatContext * s)173 static int yop_read_close(AVFormatContext *s)
174 {
175     YopDecContext *yop = s->priv_data;
176     av_packet_unref(&yop->video_packet);
177     return 0;
178 }
179 
yop_read_seek(AVFormatContext * s,int stream_index,int64_t timestamp,int flags)180 static 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     if (!stream_index)
188         return -1;
189 
190     pos_min        = s->internal->data_offset;
191     pos_max        = avio_size(s->pb) - yop->frame_size;
192     frame_count    = (pos_max - pos_min) / yop->frame_size;
193 
194     timestamp      = FFMAX(0, FFMIN(frame_count, timestamp));
195 
196     frame_pos      = timestamp * yop->frame_size + pos_min;
197 
198     if (avio_seek(s->pb, frame_pos, SEEK_SET) < 0)
199         return -1;
200 
201     av_packet_unref(&yop->video_packet);
202     yop->odd_frame = timestamp & 1;
203 
204     return 0;
205 }
206 
207 AVInputFormat ff_yop_demuxer = {
208     .name           = "yop",
209     .long_name      = NULL_IF_CONFIG_SMALL("Psygnosis YOP"),
210     .priv_data_size = sizeof(YopDecContext),
211     .read_probe     = yop_probe,
212     .read_header    = yop_read_header,
213     .read_packet    = yop_read_packet,
214     .read_close     = yop_read_close,
215     .read_seek      = yop_read_seek,
216     .extensions     = "yop",
217     .flags          = AVFMT_GENERIC_INDEX,
218 };
219