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"
28 #define LMLM4_I_FRAME 0x00
29 #define LMLM4_P_FRAME 0x01
30 #define LMLM4_B_FRAME 0x02
31 #define LMLM4_INVALID 0x03
32 #define LMLM4_MPEG1L2 0x04
34 #define LMLM4_MAX_PACKET_SIZE 1024 * 1024
36 static int lmlm4_probe(AVProbeData * pd) {
37 unsigned char *buf = pd->buf;
38 unsigned int frame_type, packet_size;
40 frame_type = AV_RB16(buf+2);
41 packet_size = AV_RB32(buf+4);
43 if (!AV_RB16(buf) && frame_type <= LMLM4_MPEG1L2 && packet_size &&
44 frame_type != LMLM4_INVALID && packet_size <= LMLM4_MAX_PACKET_SIZE) {
46 if (frame_type == LMLM4_MPEG1L2) {
47 if ((AV_RB16(buf+8) & 0xfffe) != 0xfffc)
49 /* I could calculate the audio framesize and compare with
50 * packet_size-8, but that seems overkill */
51 return AVPROBE_SCORE_MAX / 3;
52 } else if (AV_RB24(buf+8) == 0x000001) { /* PES Signal */
53 return AVPROBE_SCORE_MAX / 5;
60 static int lmlm4_read_header(AVFormatContext *s, AVFormatParameters *ap) {
63 if (!(st = av_new_stream(s, 0)))
64 return AVERROR(ENOMEM);
65 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
66 st->codec->codec_id = CODEC_ID_MPEG4;
67 st->need_parsing = AVSTREAM_PARSE_HEADERS;
68 av_set_pts_info(st, 64, 1001, 30000);
70 if (!(st = av_new_stream(s, 1)))
71 return AVERROR(ENOMEM);
72 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
73 st->codec->codec_id = CODEC_ID_MP2;
74 st->need_parsing = AVSTREAM_PARSE_HEADERS;
76 /* the parameters will be extracted from the compressed bitstream */
80 static int lmlm4_read_packet(AVFormatContext *s, AVPacket *pkt) {
81 ByteIOContext *pb = s->pb;
83 unsigned int frame_type, packet_size, padding, frame_size;
85 get_be16(pb); /* channel number */
86 frame_type = get_be16(pb);
87 packet_size = get_be32(pb);
88 padding = -packet_size & 511;
89 frame_size = packet_size - 8;
91 if (frame_type > LMLM4_MPEG1L2 || frame_type == LMLM4_INVALID) {
92 av_log(s, AV_LOG_ERROR, "invalid or unsupported frame_type\n");
95 if (packet_size > LMLM4_MAX_PACKET_SIZE) {
96 av_log(s, AV_LOG_ERROR, "packet size exceeds maximum\n");
100 if ((ret = av_get_packet(pb, pkt, frame_size)) <= 0)
103 url_fskip(pb, padding);
105 switch (frame_type) {
107 pkt->flags = AV_PKT_FLAG_KEY;
110 pkt->stream_index = 0;
113 pkt->stream_index = 1;
120 AVInputFormat ff_lmlm4_demuxer = {
122 NULL_IF_CONFIG_SMALL("lmlm4 raw format"),