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