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 FFmpeg. 9 * 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. 14 * 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. 19 * 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 23 */ 24 25#include "libavutil/intreadwrite.h" 26 27#include "avformat.h" 28#include "internal.h" 29 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 35 36#define LMLM4_MAX_PACKET_SIZE 1024 * 1024 37 38static int lmlm4_probe(const AVProbeData *pd) 39{ 40 const unsigned char *buf = pd->buf; 41 unsigned int frame_type, packet_size; 42 43 frame_type = AV_RB16(buf + 2); 44 packet_size = AV_RB32(buf + 4); 45 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) 50 return 0; 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; 56 } 57 } 58 59 return 0; 60} 61 62static int lmlm4_read_header(AVFormatContext *s) 63{ 64 AVStream *st; 65 66 if (!(st = avformat_new_stream(s, NULL))) 67 return AVERROR(ENOMEM); 68 st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO; 69 st->codecpar->codec_id = AV_CODEC_ID_MPEG4; 70 ffstream(st)->need_parsing = AVSTREAM_PARSE_HEADERS; 71 avpriv_set_pts_info(st, 64, 1001, 30000); 72 73 if (!(st = avformat_new_stream(s, NULL))) 74 return AVERROR(ENOMEM); 75 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO; 76 st->codecpar->codec_id = AV_CODEC_ID_MP2; 77 ffstream(st)->need_parsing = AVSTREAM_PARSE_HEADERS; 78 79 /* the parameters will be extracted from the compressed bitstream */ 80 return 0; 81} 82 83static int lmlm4_read_packet(AVFormatContext *s, AVPacket *pkt) 84{ 85 AVIOContext *pb = s->pb; 86 int ret; 87 unsigned int frame_type, packet_size, padding, frame_size; 88 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; 94 95 if (frame_type > LMLM4_MPEG1L2 || frame_type == LMLM4_INVALID) { 96 av_log(s, AV_LOG_ERROR, "invalid or unsupported frame_type\n"); 97 return AVERROR(EIO); 98 } 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); 101 return AVERROR(EIO); 102 } 103 104 if ((ret = av_get_packet(pb, pkt, frame_size)) <= 0) 105 return AVERROR(EIO); 106 107 avio_skip(pb, padding); 108 109 switch (frame_type) { 110 case LMLM4_I_FRAME: 111 pkt->flags = AV_PKT_FLAG_KEY; 112 case LMLM4_P_FRAME: 113 case LMLM4_B_FRAME: 114 pkt->stream_index = 0; 115 break; 116 case LMLM4_MPEG1L2: 117 pkt->stream_index = 1; 118 break; 119 } 120 121 return ret; 122} 123 124const AVInputFormat ff_lmlm4_demuxer = { 125 .name = "lmlm4", 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, 130}; 131