Libav
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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 FFmpeg. 00006 * 00007 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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 00025 00026 static int voc_probe(AVProbeData *p) 00027 { 00028 int version, check; 00029 00030 if (memcmp(p->buf, ff_voc_magic, sizeof(ff_voc_magic) - 1)) 00031 return 0; 00032 version = AV_RL16(p->buf + 22); 00033 check = AV_RL16(p->buf + 24); 00034 if (~version + 0x1234 != check) 00035 return 10; 00036 00037 return AVPROBE_SCORE_MAX; 00038 } 00039 00040 static int voc_read_header(AVFormatContext *s, AVFormatParameters *ap) 00041 { 00042 VocDecContext *voc = s->priv_data; 00043 ByteIOContext *pb = s->pb; 00044 int header_size; 00045 AVStream *st; 00046 00047 url_fskip(pb, 20); 00048 header_size = get_le16(pb) - 22; 00049 if (header_size != 4) { 00050 av_log(s, AV_LOG_ERROR, "unknown header size: %d\n", header_size); 00051 return AVERROR(ENOSYS); 00052 } 00053 url_fskip(pb, header_size); 00054 st = av_new_stream(s, 0); 00055 if (!st) 00056 return AVERROR(ENOMEM); 00057 st->codec->codec_type = AVMEDIA_TYPE_AUDIO; 00058 00059 voc->remaining_size = 0; 00060 return 0; 00061 } 00062 00063 int 00064 voc_get_packet(AVFormatContext *s, AVPacket *pkt, AVStream *st, int max_size) 00065 { 00066 VocDecContext *voc = s->priv_data; 00067 AVCodecContext *dec = st->codec; 00068 ByteIOContext *pb = s->pb; 00069 VocType type; 00070 int size; 00071 int sample_rate = 0; 00072 int channels = 1; 00073 00074 while (!voc->remaining_size) { 00075 type = get_byte(pb); 00076 if (type == VOC_TYPE_EOF) 00077 return AVERROR(EIO); 00078 voc->remaining_size = get_le24(pb); 00079 if (!voc->remaining_size) { 00080 if (url_is_streamed(s->pb)) 00081 return AVERROR(EIO); 00082 voc->remaining_size = url_fsize(pb) - url_ftell(pb); 00083 } 00084 max_size -= 4; 00085 00086 switch (type) { 00087 case VOC_TYPE_VOICE_DATA: 00088 dec->sample_rate = 1000000 / (256 - get_byte(pb)); 00089 if (sample_rate) 00090 dec->sample_rate = sample_rate; 00091 dec->channels = channels; 00092 dec->codec_id = ff_codec_get_id(ff_voc_codec_tags, get_byte(pb)); 00093 dec->bits_per_coded_sample = av_get_bits_per_sample(dec->codec_id); 00094 voc->remaining_size -= 2; 00095 max_size -= 2; 00096 channels = 1; 00097 break; 00098 00099 case VOC_TYPE_VOICE_DATA_CONT: 00100 break; 00101 00102 case VOC_TYPE_EXTENDED: 00103 sample_rate = get_le16(pb); 00104 get_byte(pb); 00105 channels = get_byte(pb) + 1; 00106 sample_rate = 256000000 / (channels * (65536 - sample_rate)); 00107 voc->remaining_size = 0; 00108 max_size -= 4; 00109 break; 00110 00111 case VOC_TYPE_NEW_VOICE_DATA: 00112 dec->sample_rate = get_le32(pb); 00113 dec->bits_per_coded_sample = get_byte(pb); 00114 dec->channels = get_byte(pb); 00115 dec->codec_id = ff_codec_get_id(ff_voc_codec_tags, get_le16(pb)); 00116 url_fskip(pb, 4); 00117 voc->remaining_size -= 12; 00118 max_size -= 12; 00119 break; 00120 00121 default: 00122 url_fskip(pb, voc->remaining_size); 00123 max_size -= voc->remaining_size; 00124 voc->remaining_size = 0; 00125 break; 00126 } 00127 } 00128 00129 dec->bit_rate = dec->sample_rate * dec->bits_per_coded_sample; 00130 00131 if (max_size <= 0) 00132 max_size = 2048; 00133 size = FFMIN(voc->remaining_size, max_size); 00134 voc->remaining_size -= size; 00135 return av_get_packet(pb, pkt, size); 00136 } 00137 00138 static int voc_read_packet(AVFormatContext *s, AVPacket *pkt) 00139 { 00140 return voc_get_packet(s, pkt, s->streams[0], 0); 00141 } 00142 00143 AVInputFormat voc_demuxer = { 00144 "voc", 00145 NULL_IF_CONFIG_SMALL("Creative Voice file format"), 00146 sizeof(VocDecContext), 00147 voc_probe, 00148 voc_read_header, 00149 voc_read_packet, 00150 .codec_tag=(const AVCodecTag* const []){ff_voc_codec_tags, 0}, 00151 };