Libav 0.7.1
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00001 /* 00002 * Creative Voice File demuxer. 00003 * Copyright (c) 2006 Aurelien Jacobs <aurel@gnuage.org> 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 00022 #include "libavutil/intreadwrite.h" 00023 #include "voc.h" 00024 #include "internal.h" 00025 00026 00027 static int voc_probe(AVProbeData *p) 00028 { 00029 int version, check; 00030 00031 if (memcmp(p->buf, ff_voc_magic, sizeof(ff_voc_magic) - 1)) 00032 return 0; 00033 version = AV_RL16(p->buf + 22); 00034 check = AV_RL16(p->buf + 24); 00035 if (~version + 0x1234 != check) 00036 return 10; 00037 00038 return AVPROBE_SCORE_MAX; 00039 } 00040 00041 static int voc_read_header(AVFormatContext *s, AVFormatParameters *ap) 00042 { 00043 VocDecContext *voc = s->priv_data; 00044 AVIOContext *pb = s->pb; 00045 int header_size; 00046 AVStream *st; 00047 00048 avio_skip(pb, 20); 00049 header_size = avio_rl16(pb) - 22; 00050 if (header_size != 4) { 00051 av_log(s, AV_LOG_ERROR, "unknown header size: %d\n", header_size); 00052 return AVERROR(ENOSYS); 00053 } 00054 avio_skip(pb, header_size); 00055 st = av_new_stream(s, 0); 00056 if (!st) 00057 return AVERROR(ENOMEM); 00058 st->codec->codec_type = AVMEDIA_TYPE_AUDIO; 00059 00060 voc->remaining_size = 0; 00061 return 0; 00062 } 00063 00064 int 00065 voc_get_packet(AVFormatContext *s, AVPacket *pkt, AVStream *st, int max_size) 00066 { 00067 VocDecContext *voc = s->priv_data; 00068 AVCodecContext *dec = st->codec; 00069 AVIOContext *pb = s->pb; 00070 VocType type; 00071 int size, tmp_codec=-1; 00072 int sample_rate = 0; 00073 int channels = 1; 00074 00075 while (!voc->remaining_size) { 00076 type = avio_r8(pb); 00077 if (type == VOC_TYPE_EOF) 00078 return AVERROR(EIO); 00079 voc->remaining_size = avio_rl24(pb); 00080 if (!voc->remaining_size) { 00081 if (!s->pb->seekable) 00082 return AVERROR(EIO); 00083 voc->remaining_size = avio_size(pb) - avio_tell(pb); 00084 } 00085 max_size -= 4; 00086 00087 switch (type) { 00088 case VOC_TYPE_VOICE_DATA: 00089 dec->sample_rate = 1000000 / (256 - avio_r8(pb)); 00090 if (sample_rate) 00091 dec->sample_rate = sample_rate; 00092 dec->channels = channels; 00093 tmp_codec = avio_r8(pb); 00094 dec->bits_per_coded_sample = av_get_bits_per_sample(dec->codec_id); 00095 voc->remaining_size -= 2; 00096 max_size -= 2; 00097 channels = 1; 00098 break; 00099 00100 case VOC_TYPE_VOICE_DATA_CONT: 00101 break; 00102 00103 case VOC_TYPE_EXTENDED: 00104 sample_rate = avio_rl16(pb); 00105 avio_r8(pb); 00106 channels = avio_r8(pb) + 1; 00107 sample_rate = 256000000 / (channels * (65536 - sample_rate)); 00108 voc->remaining_size = 0; 00109 max_size -= 4; 00110 break; 00111 00112 case VOC_TYPE_NEW_VOICE_DATA: 00113 dec->sample_rate = avio_rl32(pb); 00114 dec->bits_per_coded_sample = avio_r8(pb); 00115 dec->channels = avio_r8(pb); 00116 tmp_codec = avio_rl16(pb); 00117 avio_skip(pb, 4); 00118 voc->remaining_size -= 12; 00119 max_size -= 12; 00120 break; 00121 00122 default: 00123 avio_skip(pb, voc->remaining_size); 00124 max_size -= voc->remaining_size; 00125 voc->remaining_size = 0; 00126 break; 00127 } 00128 } 00129 00130 if (tmp_codec >= 0) { 00131 tmp_codec = ff_codec_get_id(ff_voc_codec_tags, tmp_codec); 00132 if (dec->codec_id == CODEC_ID_NONE) 00133 dec->codec_id = tmp_codec; 00134 else if (dec->codec_id != tmp_codec) 00135 av_log(s, AV_LOG_WARNING, "Ignoring mid-stream change in audio codec\n"); 00136 if (dec->codec_id == CODEC_ID_NONE) { 00137 if (s->audio_codec_id == CODEC_ID_NONE) { 00138 av_log(s, AV_LOG_ERROR, "unknown codec tag\n"); 00139 return AVERROR(EINVAL); 00140 } 00141 av_log(s, AV_LOG_WARNING, "unknown codec tag\n"); 00142 } 00143 } 00144 00145 dec->bit_rate = dec->sample_rate * dec->bits_per_coded_sample; 00146 00147 if (max_size <= 0) 00148 max_size = 2048; 00149 size = FFMIN(voc->remaining_size, max_size); 00150 voc->remaining_size -= size; 00151 return av_get_packet(pb, pkt, size); 00152 } 00153 00154 static int voc_read_packet(AVFormatContext *s, AVPacket *pkt) 00155 { 00156 return voc_get_packet(s, pkt, s->streams[0], 0); 00157 } 00158 00159 AVInputFormat ff_voc_demuxer = { 00160 "voc", 00161 NULL_IF_CONFIG_SMALL("Creative Voice file format"), 00162 sizeof(VocDecContext), 00163 voc_probe, 00164 voc_read_header, 00165 voc_read_packet, 00166 .codec_tag=(const AVCodecTag* const []){ff_voc_codec_tags, 0}, 00167 };