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| Rev | Author | Line No. | Line |
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| 4349 | Serge | 1 | /* |
| 2 | * Westwood Studios AUD Format Demuxer |
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| 3 | * Copyright (c) 2003 The ffmpeg Project |
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| 4 | * |
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| 5 | * This file is part of FFmpeg. |
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| 6 | * |
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| 7 | * FFmpeg is free software; you can redistribute it and/or |
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| 8 | * modify it under the terms of the GNU Lesser General Public |
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| 9 | * License as published by the Free Software Foundation; either |
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| 10 | * version 2.1 of the License, or (at your option) any later version. |
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| 11 | * |
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| 12 | * FFmpeg is distributed in the hope that it will be useful, |
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| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 15 | * Lesser General Public License for more details. |
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| 16 | * |
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| 17 | * You should have received a copy of the GNU Lesser General Public |
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| 18 | * License along with FFmpeg; if not, write to the Free Software |
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| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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| 20 | */ |
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| 21 | |||
| 22 | /** |
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| 23 | * @file |
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| 24 | * Westwood Studios AUD file demuxer |
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| 25 | * by Mike Melanson (melanson@pcisys.net) |
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| 26 | * for more information on the Westwood file formats, visit: |
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| 27 | * http://www.pcisys.net/~melanson/codecs/ |
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| 28 | * http://www.geocities.com/SiliconValley/8682/aud3.txt |
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| 29 | * |
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| 30 | * Implementation note: There is no definite file signature for AUD files. |
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| 31 | * The demuxer uses a probabilistic strategy for content detection. This |
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| 32 | * entails performing sanity checks on certain header values in order to |
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| 33 | * qualify a file. Refer to wsaud_probe() for the precise parameters. |
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| 34 | */ |
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| 35 | |||
| 36 | #include "libavutil/channel_layout.h" |
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| 37 | #include "libavutil/intreadwrite.h" |
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| 38 | #include "avformat.h" |
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| 39 | #include "internal.h" |
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| 40 | |||
| 41 | #define AUD_HEADER_SIZE 12 |
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| 42 | #define AUD_CHUNK_PREAMBLE_SIZE 8 |
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| 43 | #define AUD_CHUNK_SIGNATURE 0x0000DEAF |
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| 44 | |||
| 45 | static int wsaud_probe(AVProbeData *p) |
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| 46 | { |
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| 47 | int field; |
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| 48 | |||
| 49 | /* Probabilistic content detection strategy: There is no file signature |
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| 50 | * so perform sanity checks on various header parameters: |
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| 51 | * 8000 <= sample rate (16 bits) <= 48000 ==> 40001 acceptable numbers |
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| 52 | * flags <= 0x03 (2 LSBs are used) ==> 4 acceptable numbers |
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| 53 | * compression type (8 bits) = 1 or 99 ==> 2 acceptable numbers |
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| 54 | * first audio chunk signature (32 bits) ==> 1 acceptable number |
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| 55 | * The number space contains 2^64 numbers. There are 40001 * 4 * 2 * 1 = |
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| 56 | * 320008 acceptable number combinations. |
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| 57 | */ |
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| 58 | |||
| 59 | if (p->buf_size < AUD_HEADER_SIZE + AUD_CHUNK_PREAMBLE_SIZE) |
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| 60 | return 0; |
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| 61 | |||
| 62 | /* check sample rate */ |
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| 63 | field = AV_RL16(&p->buf[0]); |
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| 64 | if ((field < 8000) || (field > 48000)) |
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| 65 | return 0; |
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| 66 | |||
| 67 | /* enforce the rule that the top 6 bits of this flags field are reserved (0); |
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| 68 | * this might not be true, but enforce it until deemed unnecessary */ |
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| 69 | if (p->buf[10] & 0xFC) |
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| 70 | return 0; |
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| 71 | |||
| 72 | if (p->buf[11] != 99 && p->buf[11] != 1) |
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| 73 | return 0; |
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| 74 | |||
| 75 | /* read ahead to the first audio chunk and validate the first header signature */ |
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| 76 | if (AV_RL32(&p->buf[16]) != AUD_CHUNK_SIGNATURE) |
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| 77 | return 0; |
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| 78 | |||
| 79 | /* return 1/2 certainty since this file check is a little sketchy */ |
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| 80 | return AVPROBE_SCORE_EXTENSION; |
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| 81 | } |
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| 82 | |||
| 83 | static int wsaud_read_header(AVFormatContext *s) |
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| 84 | { |
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| 85 | AVIOContext *pb = s->pb; |
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| 86 | AVStream *st; |
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| 87 | unsigned char header[AUD_HEADER_SIZE]; |
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| 88 | int sample_rate, channels, codec; |
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| 89 | |||
| 90 | if (avio_read(pb, header, AUD_HEADER_SIZE) != AUD_HEADER_SIZE) |
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| 91 | return AVERROR(EIO); |
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| 92 | |||
| 93 | sample_rate = AV_RL16(&header[0]); |
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| 94 | channels = (header[10] & 0x1) + 1; |
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| 95 | codec = header[11]; |
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| 96 | |||
| 97 | /* initialize the audio decoder stream */ |
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| 98 | st = avformat_new_stream(s, NULL); |
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| 99 | if (!st) |
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| 100 | return AVERROR(ENOMEM); |
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| 101 | |||
| 102 | switch (codec) { |
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| 103 | case 1: |
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| 104 | if (channels != 1) { |
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| 105 | avpriv_request_sample(s, "Stereo WS-SND1"); |
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| 106 | return AVERROR_PATCHWELCOME; |
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| 107 | } |
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| 108 | st->codec->codec_id = AV_CODEC_ID_WESTWOOD_SND1; |
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| 109 | break; |
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| 110 | case 99: |
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| 111 | st->codec->codec_id = AV_CODEC_ID_ADPCM_IMA_WS; |
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| 112 | st->codec->bits_per_coded_sample = 4; |
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| 113 | st->codec->bit_rate = channels * sample_rate * 4; |
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| 114 | break; |
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| 115 | default: |
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| 116 | avpriv_request_sample(s, "Unknown codec: %d", codec); |
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| 117 | return AVERROR_PATCHWELCOME; |
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| 118 | } |
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| 119 | avpriv_set_pts_info(st, 64, 1, sample_rate); |
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| 120 | st->codec->codec_type = AVMEDIA_TYPE_AUDIO; |
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| 121 | st->codec->channels = channels; |
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| 122 | st->codec->channel_layout = channels == 1 ? AV_CH_LAYOUT_MONO : |
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| 123 | AV_CH_LAYOUT_STEREO; |
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| 124 | st->codec->sample_rate = sample_rate; |
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| 125 | |||
| 126 | return 0; |
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| 127 | } |
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| 128 | |||
| 129 | static int wsaud_read_packet(AVFormatContext *s, |
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| 130 | AVPacket *pkt) |
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| 131 | { |
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| 132 | AVIOContext *pb = s->pb; |
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| 133 | unsigned char preamble[AUD_CHUNK_PREAMBLE_SIZE]; |
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| 134 | unsigned int chunk_size; |
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| 135 | int ret = 0; |
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| 136 | AVStream *st = s->streams[0]; |
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| 137 | |||
| 138 | if (avio_read(pb, preamble, AUD_CHUNK_PREAMBLE_SIZE) != |
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| 139 | AUD_CHUNK_PREAMBLE_SIZE) |
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| 140 | return AVERROR(EIO); |
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| 141 | |||
| 142 | /* validate the chunk */ |
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| 143 | if (AV_RL32(&preamble[4]) != AUD_CHUNK_SIGNATURE) |
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| 144 | return AVERROR_INVALIDDATA; |
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| 145 | |||
| 146 | chunk_size = AV_RL16(&preamble[0]); |
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| 147 | |||
| 148 | if (st->codec->codec_id == AV_CODEC_ID_WESTWOOD_SND1) { |
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| 149 | /* For Westwood SND1 audio we need to add the output size and input |
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| 150 | size to the start of the packet to match what is in VQA. |
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| 151 | Specifically, this is needed to signal when a packet should be |
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| 152 | decoding as raw 8-bit pcm or variable-size ADPCM. */ |
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| 153 | int out_size = AV_RL16(&preamble[2]); |
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| 154 | if ((ret = av_new_packet(pkt, chunk_size + 4))) |
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| 155 | return ret; |
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| 156 | if ((ret = avio_read(pb, &pkt->data[4], chunk_size)) != chunk_size) |
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| 157 | return ret < 0 ? ret : AVERROR(EIO); |
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| 158 | AV_WL16(&pkt->data[0], out_size); |
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| 159 | AV_WL16(&pkt->data[2], chunk_size); |
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| 160 | |||
| 161 | pkt->duration = out_size; |
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| 162 | } else { |
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| 163 | ret = av_get_packet(pb, pkt, chunk_size); |
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| 164 | if (ret != chunk_size) |
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| 165 | return AVERROR(EIO); |
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| 166 | |||
| 167 | /* 2 samples/byte, 1 or 2 samples per frame depending on stereo */ |
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| 168 | pkt->duration = (chunk_size * 2) / st->codec->channels; |
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| 169 | } |
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| 170 | pkt->stream_index = st->index; |
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| 171 | |||
| 172 | return ret; |
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| 173 | } |
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| 174 | |||
| 175 | AVInputFormat ff_wsaud_demuxer = { |
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| 176 | .name = "wsaud", |
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| 177 | .long_name = NULL_IF_CONFIG_SMALL("Westwood Studios audio"), |
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| 178 | .read_probe = wsaud_probe, |
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| 179 | .read_header = wsaud_read_header, |
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| 180 | .read_packet = wsaud_read_packet, |
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| 181 | }; |