| /* |
| * Westwood Studios AUD Format Demuxer |
| * Copyright (c) 2003 The FFmpeg Project |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| /** |
| * @file |
| * Westwood Studios AUD file demuxer |
| * by Mike Melanson (melanson@pcisys.net) |
| * for more information on the Westwood file formats, visit: |
| * http://www.pcisys.net/~melanson/codecs/ |
| * http://www.geocities.com/SiliconValley/8682/aud3.txt |
| * |
| * Implementation note: There is no definite file signature for AUD files. |
| * The demuxer uses a probabilistic strategy for content detection. This |
| * entails performing sanity checks on certain header values in order to |
| * qualify a file. Refer to wsaud_probe() for the precise parameters. |
| */ |
| |
| #include "libavutil/channel_layout.h" |
| #include "libavutil/intreadwrite.h" |
| #include "avformat.h" |
| #include "internal.h" |
| |
| #define AUD_HEADER_SIZE 12 |
| #define AUD_CHUNK_PREAMBLE_SIZE 8 |
| #define AUD_CHUNK_SIGNATURE 0x0000DEAF |
| |
| static int wsaud_probe(AVProbeData *p) |
| { |
| int field; |
| |
| /* Probabilistic content detection strategy: There is no file signature |
| * so perform sanity checks on various header parameters: |
| * 8000 <= sample rate (16 bits) <= 48000 ==> 40001 acceptable numbers |
| * flags <= 0x03 (2 LSBs are used) ==> 4 acceptable numbers |
| * compression type (8 bits) = 1 or 99 ==> 2 acceptable numbers |
| * first audio chunk signature (32 bits) ==> 1 acceptable number |
| * The number space contains 2^64 numbers. There are 40001 * 4 * 2 * 1 = |
| * 320008 acceptable number combinations. |
| */ |
| |
| if (p->buf_size < AUD_HEADER_SIZE + AUD_CHUNK_PREAMBLE_SIZE) |
| return 0; |
| |
| /* check sample rate */ |
| field = AV_RL16(&p->buf[0]); |
| if ((field < 8000) || (field > 48000)) |
| return 0; |
| |
| /* enforce the rule that the top 6 bits of this flags field are reserved (0); |
| * this might not be true, but enforce it until deemed unnecessary */ |
| if (p->buf[10] & 0xFC) |
| return 0; |
| |
| if (p->buf[11] != 99 && p->buf[11] != 1) |
| return 0; |
| |
| /* read ahead to the first audio chunk and validate the first header signature */ |
| if (AV_RL32(&p->buf[16]) != AUD_CHUNK_SIGNATURE) |
| return 0; |
| |
| /* return 1/2 certainty since this file check is a little sketchy */ |
| return AVPROBE_SCORE_EXTENSION; |
| } |
| |
| static int wsaud_read_header(AVFormatContext *s) |
| { |
| AVIOContext *pb = s->pb; |
| AVStream *st; |
| unsigned char header[AUD_HEADER_SIZE]; |
| int sample_rate, channels, codec; |
| |
| if (avio_read(pb, header, AUD_HEADER_SIZE) != AUD_HEADER_SIZE) |
| return AVERROR(EIO); |
| |
| sample_rate = AV_RL16(&header[0]); |
| channels = (header[10] & 0x1) + 1; |
| codec = header[11]; |
| |
| /* initialize the audio decoder stream */ |
| st = avformat_new_stream(s, NULL); |
| if (!st) |
| return AVERROR(ENOMEM); |
| |
| switch (codec) { |
| case 1: |
| if (channels != 1) { |
| avpriv_request_sample(s, "Stereo WS-SND1"); |
| return AVERROR_PATCHWELCOME; |
| } |
| st->codec->codec_id = AV_CODEC_ID_WESTWOOD_SND1; |
| break; |
| case 99: |
| st->codec->codec_id = AV_CODEC_ID_ADPCM_IMA_WS; |
| st->codec->bits_per_coded_sample = 4; |
| st->codec->bit_rate = channels * sample_rate * 4; |
| break; |
| default: |
| avpriv_request_sample(s, "Unknown codec: %d", codec); |
| return AVERROR_PATCHWELCOME; |
| } |
| avpriv_set_pts_info(st, 64, 1, sample_rate); |
| st->codec->codec_type = AVMEDIA_TYPE_AUDIO; |
| st->codec->channels = channels; |
| st->codec->channel_layout = channels == 1 ? AV_CH_LAYOUT_MONO : |
| AV_CH_LAYOUT_STEREO; |
| st->codec->sample_rate = sample_rate; |
| |
| return 0; |
| } |
| |
| static int wsaud_read_packet(AVFormatContext *s, |
| AVPacket *pkt) |
| { |
| AVIOContext *pb = s->pb; |
| unsigned char preamble[AUD_CHUNK_PREAMBLE_SIZE]; |
| unsigned int chunk_size; |
| int ret = 0; |
| AVStream *st = s->streams[0]; |
| |
| if (avio_read(pb, preamble, AUD_CHUNK_PREAMBLE_SIZE) != |
| AUD_CHUNK_PREAMBLE_SIZE) |
| return AVERROR(EIO); |
| |
| /* validate the chunk */ |
| if (AV_RL32(&preamble[4]) != AUD_CHUNK_SIGNATURE) |
| return AVERROR_INVALIDDATA; |
| |
| chunk_size = AV_RL16(&preamble[0]); |
| |
| if (st->codec->codec_id == AV_CODEC_ID_WESTWOOD_SND1) { |
| /* For Westwood SND1 audio we need to add the output size and input |
| size to the start of the packet to match what is in VQA. |
| Specifically, this is needed to signal when a packet should be |
| decoding as raw 8-bit pcm or variable-size ADPCM. */ |
| int out_size = AV_RL16(&preamble[2]); |
| if ((ret = av_new_packet(pkt, chunk_size + 4)) < 0) |
| return ret; |
| if ((ret = avio_read(pb, &pkt->data[4], chunk_size)) != chunk_size) |
| return ret < 0 ? ret : AVERROR(EIO); |
| AV_WL16(&pkt->data[0], out_size); |
| AV_WL16(&pkt->data[2], chunk_size); |
| |
| pkt->duration = out_size; |
| } else { |
| ret = av_get_packet(pb, pkt, chunk_size); |
| if (ret != chunk_size) |
| return AVERROR(EIO); |
| |
| /* 2 samples/byte, 1 or 2 samples per frame depending on stereo */ |
| pkt->duration = (chunk_size * 2) / st->codec->channels; |
| } |
| pkt->stream_index = st->index; |
| |
| return ret; |
| } |
| |
| AVInputFormat ff_wsaud_demuxer = { |
| .name = "wsaud", |
| .long_name = NULL_IF_CONFIG_SMALL("Westwood Studios audio"), |
| .read_probe = wsaud_probe, |
| .read_header = wsaud_read_header, |
| .read_packet = wsaud_read_packet, |
| }; |
