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
|
/*
* 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"
#include "internal.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)
{
const 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)
{
AVStream *st;
if (!(st = avformat_new_stream(s, NULL)))
return AVERROR(ENOMEM);
st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
st->codec->codec_id = AV_CODEC_ID_MPEG4;
st->need_parsing = AVSTREAM_PARSE_HEADERS;
avpriv_set_pts_info(st, 64, 1001, 30000);
if (!(st = avformat_new_stream(s, NULL)))
return AVERROR(ENOMEM);
st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
st->codec->codec_id = AV_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 || packet_size<=8) {
av_log(s, AV_LOG_ERROR, "packet size %d is invalid\n", packet_size);
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 = {
.name = "lmlm4",
.long_name = NULL_IF_CONFIG_SMALL("raw lmlm4"),
.read_probe = lmlm4_probe,
.read_header = lmlm4_read_header,
.read_packet = lmlm4_read_packet,
};
|
