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