Libav 0.7.1
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00001 /* 00002 * American Laser Games MM Format Demuxer 00003 * Copyright (c) 2006 Peter Ross 00004 * 00005 * This file is part of Libav. 00006 * 00007 * Libav is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * Libav is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with Libav; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 00034 #include "libavutil/intreadwrite.h" 00035 #include "avformat.h" 00036 00037 #define MM_PREAMBLE_SIZE 6 00038 00039 #define MM_TYPE_HEADER 0x0 00040 #define MM_TYPE_INTER 0x5 00041 #define MM_TYPE_INTRA 0x8 00042 #define MM_TYPE_INTRA_HH 0xc 00043 #define MM_TYPE_INTER_HH 0xd 00044 #define MM_TYPE_INTRA_HHV 0xe 00045 #define MM_TYPE_INTER_HHV 0xf 00046 #define MM_TYPE_AUDIO 0x15 00047 #define MM_TYPE_PALETTE 0x31 00048 00049 #define MM_HEADER_LEN_V 0x16 /* video only */ 00050 #define MM_HEADER_LEN_AV 0x18 /* video + audio */ 00051 00052 #define MM_PALETTE_COUNT 128 00053 #define MM_PALETTE_SIZE (MM_PALETTE_COUNT*3) 00054 00055 typedef struct { 00056 unsigned int audio_pts, video_pts; 00057 } MmDemuxContext; 00058 00059 static int probe(AVProbeData *p) 00060 { 00061 int len, type, fps, w, h; 00062 if (p->buf_size < MM_HEADER_LEN_AV + MM_PREAMBLE_SIZE) 00063 return 0; 00064 /* the first chunk is always the header */ 00065 if (AV_RL16(&p->buf[0]) != MM_TYPE_HEADER) 00066 return 0; 00067 len = AV_RL32(&p->buf[2]); 00068 if (len != MM_HEADER_LEN_V && len != MM_HEADER_LEN_AV) 00069 return 0; 00070 fps = AV_RL16(&p->buf[8]); 00071 w = AV_RL16(&p->buf[12]); 00072 h = AV_RL16(&p->buf[14]); 00073 if (!fps || fps > 60 || !w || w > 2048 || !h || h > 2048) 00074 return 0; 00075 type = AV_RL16(&p->buf[len]); 00076 if (!type || type > 0x31) 00077 return 0; 00078 00079 /* only return half certainty since this check is a bit sketchy */ 00080 return AVPROBE_SCORE_MAX / 2; 00081 } 00082 00083 static int read_header(AVFormatContext *s, 00084 AVFormatParameters *ap) 00085 { 00086 MmDemuxContext *mm = s->priv_data; 00087 AVIOContext *pb = s->pb; 00088 AVStream *st; 00089 00090 unsigned int type, length; 00091 unsigned int frame_rate, width, height; 00092 00093 type = avio_rl16(pb); 00094 length = avio_rl32(pb); 00095 00096 if (type != MM_TYPE_HEADER) 00097 return AVERROR_INVALIDDATA; 00098 00099 /* read header */ 00100 avio_rl16(pb); /* total number of chunks */ 00101 frame_rate = avio_rl16(pb); 00102 avio_rl16(pb); /* ibm-pc video bios mode */ 00103 width = avio_rl16(pb); 00104 height = avio_rl16(pb); 00105 avio_skip(pb, length - 10); /* unknown data */ 00106 00107 /* video stream */ 00108 st = av_new_stream(s, 0); 00109 if (!st) 00110 return AVERROR(ENOMEM); 00111 st->codec->codec_type = AVMEDIA_TYPE_VIDEO; 00112 st->codec->codec_id = CODEC_ID_MMVIDEO; 00113 st->codec->codec_tag = 0; /* no fourcc */ 00114 st->codec->width = width; 00115 st->codec->height = height; 00116 av_set_pts_info(st, 64, 1, frame_rate); 00117 00118 /* audio stream */ 00119 if (length == MM_HEADER_LEN_AV) { 00120 st = av_new_stream(s, 0); 00121 if (!st) 00122 return AVERROR(ENOMEM); 00123 st->codec->codec_type = AVMEDIA_TYPE_AUDIO; 00124 st->codec->codec_tag = 0; /* no fourcc */ 00125 st->codec->codec_id = CODEC_ID_PCM_U8; 00126 st->codec->channels = 1; 00127 st->codec->sample_rate = 8000; 00128 av_set_pts_info(st, 64, 1, 8000); /* 8000 hz */ 00129 } 00130 00131 mm->audio_pts = 0; 00132 mm->video_pts = 0; 00133 return 0; 00134 } 00135 00136 static int read_packet(AVFormatContext *s, 00137 AVPacket *pkt) 00138 { 00139 MmDemuxContext *mm = s->priv_data; 00140 AVIOContext *pb = s->pb; 00141 unsigned char preamble[MM_PREAMBLE_SIZE]; 00142 unsigned int type, length; 00143 00144 while(1) { 00145 00146 if (avio_read(pb, preamble, MM_PREAMBLE_SIZE) != MM_PREAMBLE_SIZE) { 00147 return AVERROR(EIO); 00148 } 00149 00150 type = AV_RL16(&preamble[0]); 00151 length = AV_RL16(&preamble[2]); 00152 00153 switch(type) { 00154 case MM_TYPE_PALETTE : 00155 case MM_TYPE_INTER : 00156 case MM_TYPE_INTRA : 00157 case MM_TYPE_INTRA_HH : 00158 case MM_TYPE_INTER_HH : 00159 case MM_TYPE_INTRA_HHV : 00160 case MM_TYPE_INTER_HHV : 00161 /* output preamble + data */ 00162 if (av_new_packet(pkt, length + MM_PREAMBLE_SIZE)) 00163 return AVERROR(ENOMEM); 00164 memcpy(pkt->data, preamble, MM_PREAMBLE_SIZE); 00165 if (avio_read(pb, pkt->data + MM_PREAMBLE_SIZE, length) != length) 00166 return AVERROR(EIO); 00167 pkt->size = length + MM_PREAMBLE_SIZE; 00168 pkt->stream_index = 0; 00169 pkt->pts = mm->video_pts; 00170 if (type!=MM_TYPE_PALETTE) 00171 mm->video_pts++; 00172 return 0; 00173 00174 case MM_TYPE_AUDIO : 00175 if (av_get_packet(s->pb, pkt, length)<0) 00176 return AVERROR(ENOMEM); 00177 pkt->size = length; 00178 pkt->stream_index = 1; 00179 pkt->pts = mm->audio_pts++; 00180 return 0; 00181 00182 default : 00183 av_log(s, AV_LOG_INFO, "unknown chunk type 0x%x\n", type); 00184 avio_skip(pb, length); 00185 } 00186 } 00187 00188 return 0; 00189 } 00190 00191 AVInputFormat ff_mm_demuxer = { 00192 "mm", 00193 NULL_IF_CONFIG_SMALL("American Laser Games MM format"), 00194 sizeof(MmDemuxContext), 00195 probe, 00196 read_header, 00197 read_packet, 00198 };