[FFmpeg-devel] [PATCH] AAC sequence header data setup if stream copy
Michael Niedermayer
michael at niedermayer.cc
Wed Nov 18 18:37:51 CET 2015
On Wed, Nov 18, 2015 at 05:04:06PM +0200, Maksym Veremeyenko wrote:
> Hi,
>
> FLV remuxed from MPEG-TS stream does not contains *AAC sequence
> header* as result no audio with some RTMP servers like *crtmpserver*
> and YouTube.
>
> I am not a first who faced with such problem:
> http://lists.ffmpeg.org/pipermail/ffmpeg-devel/2014-May/157791.html
> http://lists.ffmpeg.org/pipermail/ffmpeg-devel/2014-June/158342.html
>
> Proposed solution differ from *Tudor SUCIU* a bit. It use the same
> idea but implementation was taken from
> *ff_aac_put_audio_specific_config*.
>
> Attached patch implement setting *AAC sequence header* in two ways.
> First way is just to set given bytes into that header:
>
> ffmpeg -re -f mpegts -i /usr/local/src/2015-11-15/M1_award.ts
> -acodec copy -vcodec copy -bsf:a aac_adtstoasc -aac_seq_header_data
> "1190" -flags +global_header -f flv rtmp://127.0.0.1/live/demo
>
> 11 90 is a two bytes of *AAC sequence header* that describe
> AAC/LC+48000Hz+stereo
>
> another way is just build it from encoder parameters:
>
> ffmpeg -re -f mpegts -i /usr/local/src/2015-11-15/M1_award.ts
> -acodec copy -vcodec copy -bsf:a aac_adtstoasc -flvflags
> aac_seq_header_detect -flags +global_header -f flv
> rtmp://127.0.0.1/live/demo
>
> but it require copying *profile* value from decoder context in ffmpeg.c:
>
> diff --git a/ffmpeg.c b/ffmpeg.c
> index c4e9280..a976f61 100644
> --- a/ffmpeg.c
> +++ b/ffmpeg.c
> @@ -2970,6 +2970,7 @@ static int transcode_init(void)
> enc_ctx->audio_service_type = dec_ctx->audio_service_type;
> enc_ctx->block_align = dec_ctx->block_align;
> enc_ctx->initial_padding = dec_ctx->delay;
> + enc_ctx->profile = dec_ctx->profile;
> #if FF_API_AUDIOENC_DELAY
> enc_ctx->delay = dec_ctx->delay;
> #endif
>
> both methods makes possible to work with *crtmpserver* and YouTube
> by simple remuxing streams for publishing
>
> --
> Maksym Veremeyenko
> ffmpeg.c | 1
> libavformat/flvenc.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 54 insertions(+)
> ebc7cedea320684411a4a4c7f6a962c939612db0 0001-AAC-sequence-header-data-setup-if-stream-copy.patch
> From afdc10c4f496d1e72a3b955513cf6891767d731a Mon Sep 17 00:00:00 2001
> From: Maksym Veremeyenko <verem at m1.tv>
> Date: Tue, 17 Nov 2015 20:02:22 +0200
> Subject: [PATCH] AAC sequence header data setup if stream copy
>
> ---
> ffmpeg.c | 1 +
> libavformat/flvenc.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 54 insertions(+), 0 deletions(-)
>
> diff --git a/ffmpeg.c b/ffmpeg.c
> index c4e9280..a976f61 100644
> --- a/ffmpeg.c
> +++ b/ffmpeg.c
> @@ -2970,6 +2970,7 @@ static int transcode_init(void)
> enc_ctx->audio_service_type = dec_ctx->audio_service_type;
> enc_ctx->block_align = dec_ctx->block_align;
> enc_ctx->initial_padding = dec_ctx->delay;
> + enc_ctx->profile = dec_ctx->profile;
> #if FF_API_AUDIOENC_DELAY
> enc_ctx->delay = dec_ctx->delay;
> #endif
> diff --git a/libavformat/flvenc.c b/libavformat/flvenc.c
> index e217ba8..6380fd7 100644
> --- a/libavformat/flvenc.c
> +++ b/libavformat/flvenc.c
> @@ -28,6 +28,9 @@
> #include "flv.h"
> #include "internal.h"
> #include "metadata.h"
> +#include "libavutil/opt.h"
> +#include "libavcodec/put_bits.h"
> +#include "libavcodec/aacenctab.h"
>
>
> static const AVCodecTag flv_video_codec_ids[] = {
> @@ -68,6 +71,10 @@ typedef struct FLVContext {
> AVCodecContext *video_enc;
> double framerate;
> AVCodecContext *data_enc;
> +
> + uint8_t *aac_seq_header_data;
> + int aac_seq_header_length;
> + int flags;
> } FLVContext;
>
> typedef struct FLVStreamContext {
> @@ -452,6 +459,37 @@ static int flv_write_header(AVFormatContext *s)
> if (enc->codec_id == AV_CODEC_ID_AAC) {
> avio_w8(pb, get_audio_flags(s, enc));
> avio_w8(pb, 0); // AAC sequence header
> + if (!enc->extradata_size && flv->aac_seq_header_data)
> + {
> + avio_write(pb, flv->aac_seq_header_data, flv->aac_seq_header_length);
> +
> + av_log(s, AV_LOG_WARNING, "AAC sequence header length=%d\n", flv->aac_seq_header_length);
> + }
> + else if (!enc->extradata_size && !flv->aac_seq_header_data && flv->flags & 1)
> + {
> + PutBitContext pbc;
> + int samplerate_index;
> + int channels = flv->audio_enc->channels - (flv->audio_enc->channels == 8 ? 1 : 0);
> + uint8_t data[2];
> +
> + for (samplerate_index = 0; samplerate_index < 16; samplerate_index++)
> + if (flv->audio_enc->sample_rate == mpeg4audio_sample_rates[samplerate_index])
> + break;
> +
> + init_put_bits(&pbc, data, sizeof(data));
> + put_bits(&pbc, 5, flv->audio_enc->profile + 1); //profile
> + put_bits(&pbc, 4, samplerate_index); //sample rate index
> + put_bits(&pbc, 4, channels);
> + put_bits(&pbc, 1, 0); //frame length - 1024 samples
> + put_bits(&pbc, 1, 0); //does not depend on core coder
> + put_bits(&pbc, 1, 0); //is not extension
> + flush_put_bits(&pbc);
> +
> + avio_w8(pb, data[0]);
> + avio_w8(pb, data[1]);
> +
> + av_log(s, AV_LOG_WARNING, "AAC sequence header: %02x %02x.\n", data[0], data[1]);
> + }
> avio_write(pb, enc->extradata, enc->extradata_size);
> } else {
> avio_w8(pb, enc->codec_tag | FLV_FRAME_KEY); // flags
> @@ -655,6 +693,20 @@ static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
> return pb->error;
> }
>
> +static const AVOption options[] = {
> + { "flvflags", "FLV muxer flags", offsetof(FLVContext, flags), AV_OPT_TYPE_FLAGS, {.i64 = 0}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "flvflags" },
> + { "aac_seq_header_detect", "Put AAC sequence header based on stream data", 0, AV_OPT_TYPE_CONST, {.i64 = 1}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "flvflags" },
> + { "aac_seq_header_data", "Put AAC sequence header data specified", offsetof(FLVContext, aac_seq_header_data), AV_OPT_TYPE_BINARY, {.str = NULL}, .flags = AV_OPT_FLAG_ENCODING_PARAM },
> + { NULL },
> +};
> +
> +static const AVClass flv_muxer_class = {
> + .class_name = "flv muxer",
> + .item_name = av_default_item_name,
> + .option = options,
> + .version = LIBAVUTIL_VERSION_INT,
> +};
> +
> AVOutputFormat ff_flv_muxer = {
> .name = "flv",
> .long_name = NULL_IF_CONFIG_SMALL("FLV (Flash Video)"),
> @@ -671,4 +723,5 @@ AVOutputFormat ff_flv_muxer = {
> },
> .flags = AVFMT_GLOBALHEADER | AVFMT_VARIABLE_FPS |
> AVFMT_TS_NONSTRICT,
> + .priv_class = &flv_muxer_class,
the first field of the context must be a AVClass
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
I know you won't believe me, but the highest form of Human Excellence is
to question oneself and others. -- Socrates
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