--- /dev/null
+/*
+ * LATM/LOAS muxer
+ * Copyright (c) 2011 Kieran Kunhya <kieran@kunhya.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavcodec/get_bits.h"
+#include "libavcodec/put_bits.h"
+#include "libavcodec/avcodec.h"
+#include "libavcodec/mpeg4audio.h"
+#include "libavutil/opt.h"
+#include "avformat.h"
+
+typedef struct {
+ int off;
+ int channel_conf;
+ int object_type;
+ int counter;
+ int mod;
+} LATMContext;
+
+static const AVOption options[] = {
+ {"smc-interval", "StreamMuxConfig interval.",
+ offsetof(LATMContext, mod), FF_OPT_TYPE_INT, {.dbl = 0x0014}, 0x0001, 0xffff, AV_OPT_FLAG_ENCODING_PARAM},
+ {NULL},
+};
+
+static const AVClass latm_muxer_class = {
+ .class_name = "LATM/LOAS muxer",
+ .item_name = av_default_item_name,
+ .option = options,
+ .version = LIBAVUTIL_VERSION_INT,
+};
+
+static int latm_decode_extradata(LATMContext *ctx, uint8_t *buf, int size)
+{
+ GetBitContext gb;
+ MPEG4AudioConfig m4ac;
+
+ init_get_bits(&gb, buf, size * 8);
+ ctx->off = ff_mpeg4audio_get_config(&m4ac, buf, size);
+ if (ctx->off < 0)
+ return ctx->off;
+ skip_bits_long(&gb, ctx->off);
+
+ /* FIXME: are any formats not allowed in LATM? */
+
+ if (m4ac.object_type > AOT_SBR && m4ac.object_type != AOT_ALS) {
+ av_log(ctx, AV_LOG_ERROR, "Muxing MPEG-4 AOT %d in LATM is not supported\n", m4ac.object_type);
+ return AVERROR_INVALIDDATA;
+ }
+ ctx->channel_conf = m4ac.chan_config;
+ ctx->object_type = m4ac.object_type;
+
+ return 0;
+}
+
+static int latm_write_header(AVFormatContext *s)
+{
+ LATMContext *ctx = s->priv_data;
+ AVCodecContext *avctx = s->streams[0]->codec;
+
+ if (avctx->extradata_size > 0 &&
+ latm_decode_extradata(ctx, avctx->extradata, avctx->extradata_size) < 0)
+ return AVERROR_INVALIDDATA;
+
+ return 0;
+}
+
+static int latm_write_frame_header(AVFormatContext *s, PutBitContext *bs)
+{
+ LATMContext *ctx = s->priv_data;
+ AVCodecContext *avctx = s->streams[0]->codec;
+ GetBitContext gb;
+ int header_size;
+
+ /* AudioMuxElement */
+ put_bits(bs, 1, !!ctx->counter);
+
+ if (!ctx->counter) {
+ init_get_bits(&gb, avctx->extradata, avctx->extradata_size * 8);
+
+ /* StreamMuxConfig */
+ put_bits(bs, 1, 0); /* audioMuxVersion */
+ put_bits(bs, 1, 1); /* allStreamsSameTimeFraming */
+ put_bits(bs, 6, 0); /* numSubFrames */
+ put_bits(bs, 4, 0); /* numProgram */
+ put_bits(bs, 3, 0); /* numLayer */
+
+ /* AudioSpecificConfig */
+ if (ctx->object_type == AOT_ALS) {
+ header_size = avctx->extradata_size-(ctx->off + 7) >> 3;
+ ff_copy_bits(bs, &avctx->extradata[ctx->off], header_size);
+ } else {
+ ff_copy_bits(bs, avctx->extradata, ctx->off + 3);
+
+ if (!ctx->channel_conf) {
+ ff_copy_pce_data(bs, &gb);
+ }
+ }
+
+ put_bits(bs, 3, 0); /* frameLengthType */
+ put_bits(bs, 8, 0); /* latmBufferFullness */
+
+ put_bits(bs, 1, 0); /* otherDataPresent */
+ put_bits(bs, 1, 0); /* crcCheckPresent */
+ }
+
+ ctx->counter++;
+ ctx->counter %= ctx->mod;
+
+ return 0;
+}
+
+static int latm_write_packet(AVFormatContext *s, AVPacket *pkt)
+{
+ AVIOContext *pb = s->pb;
+ PutBitContext bs;
+ int i, len;
+ uint8_t loas_header[] = "\x56\xe0\x00";
+ uint8_t *buf;
+
+ if (pkt->size > 2 && pkt->data[0] == 0xff && (pkt->data[1] >> 4) == 0xf) {
+ av_log(s, AV_LOG_ERROR, "ADTS header detected - ADTS will not be incorrectly muxed into LATM\n");
+ return AVERROR_INVALIDDATA;
+ }
+
+ buf = av_malloc(pkt->size+1024);
+ if (!buf)
+ return AVERROR(ENOMEM);
+
+ init_put_bits(&bs, buf, pkt->size+1024);
+
+ latm_write_frame_header(s, &bs);
+
+ /* PayloadLengthInfo() */
+ for (i = 0; i <= pkt->size-255; i+=255)
+ put_bits(&bs, 8, 255);
+
+ put_bits(&bs, 8, pkt->size-i);
+
+ /* The LATM payload is written unaligned */
+
+ /* PayloadMux() */
+ for (i = 0; i < pkt->size; i++)
+ put_bits(&bs, 8, pkt->data[i]);
+
+ align_put_bits(&bs);
+ flush_put_bits(&bs);
+
+ len = put_bits_count(&bs) >> 3;
+
+ loas_header[1] |= (len >> 8) & 0x1f;
+ loas_header[2] |= len & 0xff;
+
+ avio_write(pb, loas_header, 3);
+ avio_write(pb, buf, len);
+
+ av_free(buf);
+
+ return 0;
+}
+
+AVOutputFormat ff_latm_muxer = {
+ .name = "latm",
+ .long_name = NULL_IF_CONFIG_SMALL("LOAS/LATM"),
+ .mime_type = "audio/MP4A-LATM",
+ .extensions = "latm",
+ .priv_data_size = sizeof(LATMContext),
+ .audio_codec = CODEC_ID_AAC,
+ .video_codec = CODEC_ID_NONE,
+ .write_header = latm_write_header,
+ .write_packet = latm_write_packet,
+ .priv_class = &latm_muxer_class,
+};
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