1/*
2 * Linux Media Labs MPEG-4 demuxer
3 * Copyright (c) 2008 Ivo van Poorten
4 *
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.
7 *
8 * This file is part of Libav.
9 *
10 * Libav 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.
14 *
15 * Libav 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.
19 *
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with Libav; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25#include "libavutil/intreadwrite.h"
26#include "avformat.h"
27#include "internal.h"
28
29#define LMLM4_I_FRAME   0x00
30#define LMLM4_P_FRAME   0x01
31#define LMLM4_B_FRAME   0x02
32#define LMLM4_INVALID   0x03
33#define LMLM4_MPEG1L2   0x04
34
35#define LMLM4_MAX_PACKET_SIZE   1024 * 1024
36
37static int lmlm4_probe(AVProbeData * pd) {
38    unsigned char *buf = pd->buf;
39    unsigned int frame_type, packet_size;
40
41    frame_type  = AV_RB16(buf+2);
42    packet_size = AV_RB32(buf+4);
43
44    if (!AV_RB16(buf) && frame_type <= LMLM4_MPEG1L2 && packet_size &&
45        frame_type != LMLM4_INVALID && packet_size <= LMLM4_MAX_PACKET_SIZE) {
46
47        if (frame_type == LMLM4_MPEG1L2) {
48            if ((AV_RB16(buf+8) & 0xfffe) != 0xfffc)
49                return 0;
50            /* I could calculate the audio framesize and compare with
51             * packet_size-8, but that seems overkill */
52            return AVPROBE_SCORE_MAX / 3;
53        } else if (AV_RB24(buf+8) == 0x000001) {    /* PES Signal */
54            return AVPROBE_SCORE_MAX / 5;
55        }
56    }
57
58    return 0;
59}
60
61static int lmlm4_read_header(AVFormatContext *s, AVFormatParameters *ap) {
62    AVStream *st;
63
64    if (!(st = avformat_new_stream(s, NULL)))
65        return AVERROR(ENOMEM);
66    st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
67    st->codec->codec_id   = CODEC_ID_MPEG4;
68    st->need_parsing      = AVSTREAM_PARSE_HEADERS;
69    avpriv_set_pts_info(st, 64, 1001, 30000);
70
71    if (!(st = avformat_new_stream(s, NULL)))
72        return AVERROR(ENOMEM);
73    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
74    st->codec->codec_id   = CODEC_ID_MP2;
75    st->need_parsing      = AVSTREAM_PARSE_HEADERS;
76
77    /* the parameters will be extracted from the compressed bitstream */
78    return 0;
79}
80
81static int lmlm4_read_packet(AVFormatContext *s, AVPacket *pkt) {
82    AVIOContext *pb = s->pb;
83    int ret;
84    unsigned int frame_type, packet_size, padding, frame_size;
85
86    avio_rb16(pb);                       /* channel number */
87    frame_type  = avio_rb16(pb);
88    packet_size = avio_rb32(pb);
89    padding     = -packet_size & 511;
90    frame_size  = packet_size - 8;
91
92    if (frame_type > LMLM4_MPEG1L2 || frame_type == LMLM4_INVALID) {
93        av_log(s, AV_LOG_ERROR, "invalid or unsupported frame_type\n");
94        return AVERROR(EIO);
95    }
96    if (packet_size > LMLM4_MAX_PACKET_SIZE) {
97        av_log(s, AV_LOG_ERROR, "packet size exceeds maximum\n");
98        return AVERROR(EIO);
99    }
100
101    if ((ret = av_get_packet(pb, pkt, frame_size)) <= 0)
102        return AVERROR(EIO);
103
104    avio_skip(pb, padding);
105
106    switch (frame_type) {
107        case LMLM4_I_FRAME:
108            pkt->flags = AV_PKT_FLAG_KEY;
109        case LMLM4_P_FRAME:
110        case LMLM4_B_FRAME:
111            pkt->stream_index = 0;
112            break;
113        case LMLM4_MPEG1L2:
114            pkt->stream_index = 1;
115            break;
116    }
117
118    return ret;
119}
120
121AVInputFormat ff_lmlm4_demuxer = {
122    .name           = "lmlm4",
123    .long_name      = NULL_IF_CONFIG_SMALL("lmlm4 raw format"),
124    .read_probe     = lmlm4_probe,
125    .read_header    = lmlm4_read_header,
126    .read_packet    = lmlm4_read_packet,
127};
128