1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
|
/*
* TechnoTrend PVA (.pva) demuxer
* Copyright (c) 2007, 2008 Ivo van Poorten
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avformat.h"
#include "mpeg.h"
#define PVA_MAX_PAYLOAD_LENGTH 0x17f8
#define PVA_VIDEO_PAYLOAD 0x01
#define PVA_AUDIO_PAYLOAD 0x02
#define PVA_MAGIC (('A' << 8) + 'V')
typedef struct {
int continue_pes;
} PVAContext;
static int pva_probe(AVProbeData * pd) {
unsigned char *buf = pd->buf;
if (AV_RB16(buf) == PVA_MAGIC && buf[2] && buf[2] < 3 && buf[4] == 0x55)
return AVPROBE_SCORE_MAX / 2;
return 0;
}
static int pva_read_header(AVFormatContext *s, AVFormatParameters *ap) {
AVStream *st;
if (!(st = av_new_stream(s, 0)))
return AVERROR(ENOMEM);
st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
st->codec->codec_id = CODEC_ID_MPEG2VIDEO;
st->need_parsing = AVSTREAM_PARSE_FULL;
av_set_pts_info(st, 32, 1, 90000);
av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME);
if (!(st = av_new_stream(s, 1)))
return AVERROR(ENOMEM);
st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
st->codec->codec_id = CODEC_ID_MP2;
st->need_parsing = AVSTREAM_PARSE_FULL;
av_set_pts_info(st, 33, 1, 90000);
av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME);
/* the parameters will be extracted from the compressed bitstream */
return 0;
}
#define pva_log if (read_packet) av_log
static int read_part_of_packet(AVFormatContext *s, int64_t *pts,
int *len, int *strid, int read_packet) {
AVIOContext *pb = s->pb;
PVAContext *pvactx = s->priv_data;
int syncword, streamid, reserved, flags, length, pts_flag;
int64_t pva_pts = AV_NOPTS_VALUE, startpos;
recover:
startpos = url_ftell(pb);
syncword = avio_rb16(pb);
streamid = avio_r8(pb);
avio_r8(pb); /* counter not used */
reserved = avio_r8(pb);
flags = avio_r8(pb);
length = avio_rb16(pb);
pts_flag = flags & 0x10;
if (syncword != PVA_MAGIC) {
pva_log(s, AV_LOG_ERROR, "invalid syncword\n");
return AVERROR(EIO);
}
if (streamid != PVA_VIDEO_PAYLOAD && streamid != PVA_AUDIO_PAYLOAD) {
pva_log(s, AV_LOG_ERROR, "invalid streamid\n");
return AVERROR(EIO);
}
if (reserved != 0x55) {
pva_log(s, AV_LOG_WARNING, "expected reserved byte to be 0x55\n");
}
if (length > PVA_MAX_PAYLOAD_LENGTH) {
pva_log(s, AV_LOG_ERROR, "invalid payload length %u\n", length);
return AVERROR(EIO);
}
if (streamid == PVA_VIDEO_PAYLOAD && pts_flag) {
pva_pts = avio_rb32(pb);
length -= 4;
} else if (streamid == PVA_AUDIO_PAYLOAD) {
/* PVA Audio Packets either start with a signaled PES packet or
* are a continuation of the previous PES packet. New PES packets
* always start at the beginning of a PVA Packet, never somewhere in
* the middle. */
if (!pvactx->continue_pes) {
int pes_signal, pes_header_data_length, pes_packet_length,
pes_flags;
unsigned char pes_header_data[256];
pes_signal = avio_rb24(pb);
avio_r8(pb);
pes_packet_length = avio_rb16(pb);
pes_flags = avio_rb16(pb);
pes_header_data_length = avio_r8(pb);
if (pes_signal != 1) {
pva_log(s, AV_LOG_WARNING, "expected signaled PES packet, "
"trying to recover\n");
avio_seek(pb, length - 9, SEEK_CUR);
if (!read_packet)
return AVERROR(EIO);
goto recover;
}
avio_read(pb, pes_header_data, pes_header_data_length);
length -= 9 + pes_header_data_length;
pes_packet_length -= 3 + pes_header_data_length;
pvactx->continue_pes = pes_packet_length;
if (pes_flags & 0x80 && (pes_header_data[0] & 0xf0) == 0x20)
pva_pts = ff_parse_pes_pts(pes_header_data);
}
pvactx->continue_pes -= length;
if (pvactx->continue_pes < 0) {
pva_log(s, AV_LOG_WARNING, "audio data corruption\n");
pvactx->continue_pes = 0;
}
}
if (pva_pts != AV_NOPTS_VALUE)
av_add_index_entry(s->streams[streamid-1], startpos, pva_pts, 0, 0, AVINDEX_KEYFRAME);
*pts = pva_pts;
*len = length;
*strid = streamid;
return 0;
}
static int pva_read_packet(AVFormatContext *s, AVPacket *pkt) {
AVIOContext *pb = s->pb;
int64_t pva_pts;
int ret, length, streamid;
if (read_part_of_packet(s, &pva_pts, &length, &streamid, 1) < 0 ||
(ret = av_get_packet(pb, pkt, length)) <= 0)
return AVERROR(EIO);
pkt->stream_index = streamid - 1;
pkt->pts = pva_pts;
return ret;
}
static int64_t pva_read_timestamp(struct AVFormatContext *s, int stream_index,
int64_t *pos, int64_t pos_limit) {
AVIOContext *pb = s->pb;
PVAContext *pvactx = s->priv_data;
int length, streamid;
int64_t res = AV_NOPTS_VALUE;
pos_limit = FFMIN(*pos+PVA_MAX_PAYLOAD_LENGTH*8, (uint64_t)*pos+pos_limit);
while (*pos < pos_limit) {
res = AV_NOPTS_VALUE;
avio_seek(pb, *pos, SEEK_SET);
pvactx->continue_pes = 0;
if (read_part_of_packet(s, &res, &length, &streamid, 0)) {
(*pos)++;
continue;
}
if (streamid - 1 != stream_index || res == AV_NOPTS_VALUE) {
*pos = url_ftell(pb) + length;
continue;
}
break;
}
pvactx->continue_pes = 0;
return res;
}
AVInputFormat ff_pva_demuxer = {
"pva",
NULL_IF_CONFIG_SMALL("TechnoTrend PVA file and stream format"),
sizeof(PVAContext),
pva_probe,
pva_read_header,
pva_read_packet,
.read_timestamp = pva_read_timestamp
};
|
