187 lines
6.3 KiB
C
Executable file
187 lines
6.3 KiB
C
Executable file
/*
|
|
* 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(const 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->codecpar->codec_id = AV_CODEC_ID_WESTWOOD_SND1;
|
|
break;
|
|
case 99:
|
|
st->codecpar->codec_id = AV_CODEC_ID_ADPCM_IMA_WS;
|
|
st->codecpar->bits_per_coded_sample = 4;
|
|
st->codecpar->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->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
|
|
st->codecpar->channels = channels;
|
|
st->codecpar->channel_layout = channels == 1 ? AV_CH_LAYOUT_MONO :
|
|
AV_CH_LAYOUT_STEREO;
|
|
st->codecpar->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->codecpar->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);
|
|
|
|
if (st->codecpar->channels <= 0) {
|
|
av_log(s, AV_LOG_ERROR, "invalid number of channels %d\n",
|
|
st->codecpar->channels);
|
|
return AVERROR_INVALIDDATA;
|
|
}
|
|
|
|
/* 2 samples/byte, 1 or 2 samples per frame depending on stereo */
|
|
pkt->duration = (chunk_size * 2) / st->codecpar->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,
|
|
};
|