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
|
/*
* Linux Media Labs MPEG-4 demuxer
* Copyright (c) 2008 Ivo van Poorten
*
* Due to a lack of sample files, only files with one channel are supported.
* u-law and ADPCM audio are unsupported for the same reason.
*
* 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 "libavutil/intreadwrite.h"
#include "avformat.h"
#define LMLM4_I_FRAME 0x00
#define LMLM4_P_FRAME 0x01
#define LMLM4_B_FRAME 0x02
#define LMLM4_INVALID 0x03
#define LMLM4_MPEG1L2 0x04
#define LMLM4_MAX_PACKET_SIZE 1024 * 1024
static int lmlm4_probe(AVProbeData * pd) {
unsigned char *buf = pd->buf;
unsigned int frame_type, packet_size;
frame_type = AV_RB16(buf+2);
packet_size = AV_RB32(buf+4);
if (!AV_RB16(buf) && frame_type <= LMLM4_MPEG1L2 && packet_size &&
frame_type != LMLM4_INVALID && packet_size <= LMLM4_MAX_PACKET_SIZE) {
if (frame_type == LMLM4_MPEG1L2) {
if ((AV_RB16(buf+8) & 0xfffe) != 0xfffc)
return 0;
/* I could calculate the audio framesize and compare with
* packet_size-8, but that seems overkill */
return AVPROBE_SCORE_MAX / 3;
} else if (AV_RB24(buf+8) == 0x000001) { /* PES Signal */
return AVPROBE_SCORE_MAX / 5;
}
}
return 0;
}
static int lmlm4_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_MPEG4;
st->need_parsing = AVSTREAM_PARSE_HEADERS;
av_set_pts_info(st, 64, 1001, 30000);
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_HEADERS;
/* the parameters will be extracted from the compressed bitstream */
return 0;
}
static int lmlm4_read_packet(AVFormatContext *s, AVPacket *pkt) {
AVIOContext *pb = s->pb;
int ret;
unsigned int frame_type, packet_size, padding, frame_size;
avio_rb16(pb); /* channel number */
frame_type = avio_rb16(pb);
packet_size = avio_rb32(pb);
padding = -packet_size & 511;
frame_size = packet_size - 8;
if (frame_type > LMLM4_MPEG1L2 || frame_type == LMLM4_INVALID) {
av_log(s, AV_LOG_ERROR, "invalid or unsupported frame_type\n");
return AVERROR(EIO);
}
if (packet_size > LMLM4_MAX_PACKET_SIZE) {
av_log(s, AV_LOG_ERROR, "packet size exceeds maximum\n");
return AVERROR(EIO);
}
if ((ret = av_get_packet(pb, pkt, frame_size)) <= 0)
return AVERROR(EIO);
avio_skip(pb, padding);
switch (frame_type) {
case LMLM4_I_FRAME:
pkt->flags = AV_PKT_FLAG_KEY;
case LMLM4_P_FRAME:
case LMLM4_B_FRAME:
pkt->stream_index = 0;
break;
case LMLM4_MPEG1L2:
pkt->stream_index = 1;
break;
}
return ret;
}
AVInputFormat ff_lmlm4_demuxer = {
"lmlm4",
NULL_IF_CONFIG_SMALL("lmlm4 raw format"),
0,
lmlm4_probe,
lmlm4_read_header,
lmlm4_read_packet,
};
|
