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/*
* Copyright (c) 2021 Aidan Richmond
*
* 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 muxer
* by Aidan Richmond (aidan.is@hotmail.co.uk)
*
* This muxer supports IMA ADPCM packed in westwoods format.
*
* @see http://xhp.xwis.net/documents/aud3.txt
*/
#include "libavutil/avassert.h"
#include "avformat.h"
#include "avio_internal.h"
#include "internal.h"
#include <stdint.h>
#define AUD_CHUNK_SIGNATURE 0x0000DEAF
typedef struct AUDMuxContext {
int uncomp_size;
int size;
} AUDMuxContext;
static int wsaud_write_init(AVFormatContext *ctx)
{
AVStream *st = ctx->streams[0];
AVIOContext *pb = ctx->pb;
/* Stream must be seekable to correctly write the file. */
if (!(pb->seekable & AVIO_SEEKABLE_NORMAL)) {
av_log(ctx->streams[0], AV_LOG_ERROR, "Cannot write Westwood AUD to"
" non-seekable stream.\n");
return AVERROR(EINVAL);
}
if (st->codecpar->codec_id != AV_CODEC_ID_ADPCM_IMA_WS) {
av_log(st, AV_LOG_ERROR, "%s codec not supported for Westwood AUD.\n",
avcodec_get_name(st->codecpar->codec_id));
return AVERROR(EINVAL);
}
if (ctx->nb_streams != 1) {
av_log(st, AV_LOG_ERROR, "AUD files have exactly one stream\n");
return AVERROR(EINVAL);
}
return 0;
}
static int wsaud_write_header(AVFormatContext *ctx)
{
AVStream *st = ctx->streams[0];
AVIOContext *pb = ctx->pb;
AUDMuxContext *a = ctx->priv_data;
unsigned char flags = 0;
a->uncomp_size = 0;
a->size = 0;
/* Flag if we have stereo data. */
if (st->codecpar->channels == 2)
flags |= 1;
/* This flags that the file contains 16 bit samples rather than 8 bit
since the encoder only encodes 16 bit samples this should be set. */
if (av_get_bits_per_sample(st->codecpar->codec_id) == 4)
flags |= 2;
avio_wl16(pb, st->codecpar->sample_rate);
/* We don't know the file size yet, so just zero 8 bytes */
ffio_fill(pb, 0, 8);
avio_w8(pb, flags);
/* 99 indicates the ADPCM format. Other formats not supported. */
avio_w8(pb, 99);
return 0;
}
static int wsaud_write_packet(AVFormatContext *ctx, AVPacket *pkt)
{
AVIOContext *pb = ctx->pb;
AUDMuxContext *a = ctx->priv_data;
if (pkt->size > UINT16_MAX / 4)
return AVERROR_INVALIDDATA;
/* Assumes ADPCM since this muxer doesn't support SND1 or PCM format. */
avio_wl16(pb, pkt->size);
avio_wl16(pb, pkt->size * 4);
avio_wl32(pb, AUD_CHUNK_SIGNATURE);
avio_write(pb, pkt->data, pkt->size);
a->size += pkt->size + 8;
a->uncomp_size += pkt->size * 4;
return 0;
}
static int wsaud_write_trailer(AVFormatContext *ctx)
{
AVIOContext *pb = ctx->pb;
AUDMuxContext *a = ctx->priv_data;
avio_seek(pb, 2, SEEK_SET);
avio_wl32(pb, a->size);
avio_wl32(pb, a->uncomp_size);
return 0;
}
const AVOutputFormat ff_wsaud_muxer = {
.name = "wsaud",
.long_name = NULL_IF_CONFIG_SMALL("Westwood Studios audio"),
.extensions = "aud",
.priv_data_size = sizeof(AUDMuxContext),
.audio_codec = AV_CODEC_ID_ADPCM_IMA_WS,
.video_codec = AV_CODEC_ID_NONE,
.init = wsaud_write_init,
.write_header = wsaud_write_header,
.write_packet = wsaud_write_packet,
.write_trailer = wsaud_write_trailer,
};
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