2 * Linux Media Labs MPEG-4 demuxer
3 * Copyright (c) 2008 Ivo van Poorten
5 * Due to a lack of sample files, only files with one channel are supported.
6 * u-law and ADPCM audio are unsupported for the same reason.
8 * This file is part of FFmpeg.
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.
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.
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
25 #include "libavutil/intreadwrite.h"
30 #define LMLM4_I_FRAME 0x00
31 #define LMLM4_P_FRAME 0x01
32 #define LMLM4_B_FRAME 0x02
33 #define LMLM4_INVALID 0x03
34 #define LMLM4_MPEG1L2 0x04
36 #define LMLM4_MAX_PACKET_SIZE 1024 * 1024
38 static int lmlm4_probe(AVProbeData
*pd
)
40 const unsigned char *buf
= pd
->buf
;
41 unsigned int frame_type
, packet_size
;
43 frame_type
= AV_RB16(buf
+ 2);
44 packet_size
= AV_RB32(buf
+ 4);
46 if (!AV_RB16(buf
) && frame_type
<= LMLM4_MPEG1L2
&& packet_size
&&
47 frame_type
!= LMLM4_INVALID
&& packet_size
<= LMLM4_MAX_PACKET_SIZE
) {
48 if (frame_type
== LMLM4_MPEG1L2
) {
49 if ((AV_RB16(buf
+ 8) & 0xfffe) != 0xfffc)
51 /* I could calculate the audio framesize and compare with
52 * packet_size-8, but that seems overkill */
53 return AVPROBE_SCORE_MAX
/ 3;
54 } else if (AV_RB24(buf
+ 8) == 0x000001) { /* PES Signal */
55 return AVPROBE_SCORE_MAX
/ 5;
62 static int lmlm4_read_header(AVFormatContext
*s
)
66 if (!(st
= avformat_new_stream(s
, NULL
)))
67 return AVERROR(ENOMEM
);
68 st
->codec
->codec_type
= AVMEDIA_TYPE_VIDEO
;
69 st
->codec
->codec_id
= AV_CODEC_ID_MPEG4
;
70 st
->need_parsing
= AVSTREAM_PARSE_HEADERS
;
71 avpriv_set_pts_info(st
, 64, 1001, 30000);
73 if (!(st
= avformat_new_stream(s
, NULL
)))
74 return AVERROR(ENOMEM
);
75 st
->codec
->codec_type
= AVMEDIA_TYPE_AUDIO
;
76 st
->codec
->codec_id
= AV_CODEC_ID_MP2
;
77 st
->need_parsing
= AVSTREAM_PARSE_HEADERS
;
79 /* the parameters will be extracted from the compressed bitstream */
83 static int lmlm4_read_packet(AVFormatContext
*s
, AVPacket
*pkt
)
85 AVIOContext
*pb
= s
->pb
;
87 unsigned int frame_type
, packet_size
, padding
, frame_size
;
89 avio_rb16(pb
); /* channel number */
90 frame_type
= avio_rb16(pb
);
91 packet_size
= avio_rb32(pb
);
92 padding
= -packet_size
& 511;
93 frame_size
= packet_size
- 8;
95 if (frame_type
> LMLM4_MPEG1L2
|| frame_type
== LMLM4_INVALID
) {
96 av_log(s
, AV_LOG_ERROR
, "invalid or unsupported frame_type\n");
99 if (packet_size
> LMLM4_MAX_PACKET_SIZE
|| packet_size
<=8) {
100 av_log(s
, AV_LOG_ERROR
, "packet size %d is invalid\n", packet_size
);
104 if ((ret
= av_get_packet(pb
, pkt
, frame_size
)) <= 0)
107 avio_skip(pb
, padding
);
109 switch (frame_type
) {
111 pkt
->flags
= AV_PKT_FLAG_KEY
;
114 pkt
->stream_index
= 0;
117 pkt
->stream_index
= 1;
124 AVInputFormat ff_lmlm4_demuxer
= {
126 .long_name
= NULL_IF_CONFIG_SMALL("raw lmlm4"),
127 .read_probe
= lmlm4_probe
,
128 .read_header
= lmlm4_read_header
,
129 .read_packet
= lmlm4_read_packet
,