--- /dev/null
+/*
+ * 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;
+ int ret;
+ 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;
+
+ av_assert1(pkt->size < UINT16_MAX && (pkt->size * 4) < UINT16_MAX);
+ /* 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;
+}
+
+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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