diff ffmpeg/libavformat/latmenc.c @ 11:f445c3017523

new files

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ffmpeg/libavformat/latmenc.c	Sun Apr 21 11:16:23 2013 +0200
@@ -0,0 +1,230 @@
+/*
+ * LATM/LOAS muxer
+ * Copyright (c) 2011 Kieran Kunhya <[e-mail]>
+ *
+ * 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"
+#include "rawenc.h"
+
+#define MAX_EXTRADATA_SIZE 1024
+
+typedef struct {
+    AVClass *av_class;
+    int off;
+    int channel_conf;
+    int object_type;
+    int counter;
+    int mod;
+    uint8_t buffer[0x1fff + MAX_EXTRADATA_SIZE + 1024];
+} LATMContext;
+
+static const AVOption options[] = {
+    {"smc-interval", "StreamMuxConfig interval.",
+     offsetof(LATMContext, mod), AV_OPT_TYPE_INT, {.i64 = 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)
+{
+    MPEG4AudioConfig m4ac;
+
+    if (size > MAX_EXTRADATA_SIZE) {
+        av_log(ctx, AV_LOG_ERROR, "Extradata is larger than currently supported.\n");
+        return AVERROR_INVALIDDATA;
+    }
+    ctx->off = avpriv_mpeg4audio_get_config(&m4ac, buf, size * 8, 1);
+    if (ctx->off < 0)
+        return ctx->off;
+
+    if (ctx->object_type == AOT_ALS && (ctx->off & 7)) {
+        // as long as avpriv_mpeg4audio_get_config works correctly this is impossible
+        av_log(ctx, AV_LOG_ERROR, "BUG: ALS offset is not byte-aligned\n");
+        return AVERROR_INVALIDDATA;
+    }
+    /* 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->codec_id == AV_CODEC_ID_AAC_LATM)
+        return 0;
+
+    if (avctx->extradata_size > 0 &&
+        latm_decode_extradata(ctx, avctx->extradata, avctx->extradata_size) < 0)
+        return AVERROR_INVALIDDATA;
+
+    return 0;
+}
+
+static void latm_write_frame_header(AVFormatContext *s, PutBitContext *bs)
+{
+    LATMContext *ctx = s->priv_data;
+    AVCodecContext *avctx = s->streams[0]->codec;
+    int header_size;
+
+    /* AudioMuxElement */
+    put_bits(bs, 1, !!ctx->counter);
+
+    if (!ctx->counter) {
+        /* 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 >> 3);
+            avpriv_copy_bits(bs, &avctx->extradata[ctx->off >> 3], header_size);
+        } else {
+            // + 3 assumes not scalable and dependsOnCoreCoder == 0,
+            // see decode_ga_specific_config in libavcodec/aacdec.c
+            avpriv_copy_bits(bs, avctx->extradata, ctx->off + 3);
+
+            if (!ctx->channel_conf) {
+                GetBitContext gb;
+                init_get_bits(&gb, avctx->extradata, avctx->extradata_size * 8);
+                skip_bits_long(&gb, ctx->off + 3);
+                avpriv_copy_pce_data(bs, &gb);
+            }
+        }
+
+        put_bits(bs, 3, 0); /* frameLengthType */
+        put_bits(bs, 8, 0xff); /* latmBufferFullness */
+
+        put_bits(bs, 1, 0); /* otherDataPresent */
+        put_bits(bs, 1, 0); /* crcCheckPresent */
+    }
+
+    ctx->counter++;
+    ctx->counter %= ctx->mod;
+}
+
+static int latm_write_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    LATMContext *ctx = s->priv_data;
+    AVIOContext *pb = s->pb;
+    PutBitContext bs;
+    int i, len;
+    uint8_t loas_header[] = "\x56\xe0\x00";
+
+    if (s->streams[0]->codec->codec_id == AV_CODEC_ID_AAC_LATM)
+        return ff_raw_write_packet(s, pkt);
+
+    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;
+    }
+
+    if (!s->streams[0]->codec->extradata) {
+        if(pkt->size > 2 && pkt->data[0] == 0x56 && (pkt->data[1] >> 4) == 0xe &&
+            (AV_RB16(pkt->data + 1) & 0x1FFF) + 3 == pkt->size)
+            return ff_raw_write_packet(s, pkt);
+        else
+            return AVERROR_INVALIDDATA;
+    }
+
+    if (pkt->size > 0x1fff)
+        goto too_large;
+
+    init_put_bits(&bs, ctx->buffer, pkt->size+1024+MAX_EXTRADATA_SIZE);
+
+    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() */
+    if (pkt->size && (pkt->data[0] & 0xe1) == 0x81) {
+        // Convert byte-aligned DSE to non-aligned.
+        // Due to the input format encoding we know that
+        // it is naturally byte-aligned in the input stream,
+        // so there are no padding bits to account for.
+        // To avoid having to add padding bits and rearrange
+        // the whole stream we just remove the byte-align flag.
+        // This allows us to remux our FATE AAC samples into latm
+        // files that are still playable with minimal effort.
+        put_bits(&bs, 8, pkt->data[0] & 0xfe);
+        avpriv_copy_bits(&bs, pkt->data + 1, 8*pkt->size - 8);
+    } else
+        avpriv_copy_bits(&bs, pkt->data, 8*pkt->size);
+
+    avpriv_align_put_bits(&bs);
+    flush_put_bits(&bs);
+
+    len = put_bits_count(&bs) >> 3;
+
+    if (len > 0x1fff)
+        goto too_large;
+
+    loas_header[1] |= (len >> 8) & 0x1f;
+    loas_header[2] |= len & 0xff;
+
+    avio_write(pb, loas_header, 3);
+    avio_write(pb, ctx->buffer, len);
+
+    return 0;
+
+too_large:
+    av_log(s, AV_LOG_ERROR, "LATM packet size larger than maximum size 0x1fff\n");
+    return AVERROR_INVALIDDATA;
+}
+
+AVOutputFormat ff_latm_muxer = {
+    .name           = "latm",
+    .long_name      = NULL_IF_CONFIG_SMALL("LOAS/LATM"),
+    .mime_type      = "audio/MP4A-LATM",
+    .extensions     = "latm,loas",
+    .priv_data_size = sizeof(LATMContext),
+    .audio_codec    = AV_CODEC_ID_AAC,
+    .video_codec    = AV_CODEC_ID_NONE,
+    .write_header   = latm_write_header,
+    .write_packet   = latm_write_packet,
+    .priv_class     = &latm_muxer_class,
+};