[FFmpeg-devel] [PATCH] avformat/flvenc: add flv live stream flag
Steven Liu
lingjiujianke at gmail.com
Fri Sep 30 08:23:37 EEST 2016
2016-09-30 0:53 GMT+08:00 Michael Niedermayer <michael at niedermayer.cc>:
> On Thu, Sep 29, 2016 at 09:25:35PM +0800, Steven Liu wrote:
> > patch update
> >
> > merge 1/2 and 2/2 into one patch
>
> > doc/muxers.texi | 5 +++++
> > libavformat/flvenc.c | 50 +++++++++++++++++++++++++++++-
> --------------------
> > 2 files changed, 34 insertions(+), 21 deletions(-)
> > f2c4c83d362faf1819b3aa72fc5608603f824dc1 0001-avformat-flvenc-add-flv-
> live-stream-flag.patch
> > From 7f5ff0d89c19e1683f91befb77ba4a7bf7b66252 Mon Sep 17 00:00:00 2001
> > From: Steven Liu <lingjiujianke at gmail.com>
> > Date: Thu, 29 Sep 2016 21:20:34 +0800
> > Subject: [PATCH] avformat/flvenc: add flv live stream flag
> >
> > If the flv format is used for live stream on publish
> > ffmpeg should not update dutration and filesize at the end.
> > because the live stream is sent metadata at first step.
> >
> > Reviewed-by: Carl Eugen Hoyos <cehoyos at ag.or.at>
> > Signed-off-by: Steven Liu <lingjiujianke at gmail.com>
> > ---
> > doc/muxers.texi | 5 +++++
> > libavformat/flvenc.c | 50 +++++++++++++++++++++++++++++-
> --------------------
> > 2 files changed, 34 insertions(+), 21 deletions(-)
> >
> > diff --git a/doc/muxers.texi b/doc/muxers.texi
> > index 27d1038..aa20656 100644
> > --- a/doc/muxers.texi
> > +++ b/doc/muxers.texi
> > @@ -148,6 +148,11 @@ Place AAC sequence header based on audio stream
> data.
> > @item no_sequence_end
> > Disable sequence end tag.
> > @end table
> > +
> > + at item live_stream
> > +Disable the duration and filesize update in the flv metadata.
> > + at end table
> > +
> > @end table
> >
> > @anchor{framecrc}
> > diff --git a/libavformat/flvenc.c b/libavformat/flvenc.c
> > index 99903f5..cd9ca84 100644
> > --- a/libavformat/flvenc.c
> > +++ b/libavformat/flvenc.c
> > @@ -64,6 +64,7 @@ static const AVCodecTag flv_audio_codec_ids[] = {
> > typedef enum {
> > FLV_AAC_SEQ_HEADER_DETECT = (1 << 0),
> > FLV_NO_SEQUENCE_END = (1 << 1),
> > + FLV_LIVE_STREAM = (1 << 2),
> > } FLVFlags;
> >
> > typedef struct FLVContext {
> > @@ -234,17 +235,18 @@ static void write_metadata(AVFormatContext *s,
> unsigned int ts)
> > metadata_count_pos = avio_tell(pb);
> > metadata_count = 4 * !!flv->video_par +
> > 5 * !!flv->audio_par +
> > - 1 * !!flv->data_par +
> > - 2; // +2 for duration and file size
> > + 1 * !!flv->data_par;
> >
> > avio_wb32(pb, metadata_count);
> >
> > - put_amf_string(pb, "duration");
> > - flv->duration_offset = avio_tell(pb);
> > -
> > - // fill in the guessed duration, it'll be corrected later if
> incorrect
> > - put_amf_double(pb, s->duration / AV_TIME_BASE);
> > + if (!(flv->flags & FLV_LIVE_STREAM)) {
> > + put_amf_string(pb, "duration");
> > + flv->duration_offset = avio_tell(pb);
> >
> > + // fill in the guessed duration, it'll be corrected later if
> incorrect
> > + put_amf_double(pb, s->duration / AV_TIME_BASE);
> > + metadata_count++;
> > + }
> > if (flv->video_par) {
> > put_amf_string(pb, "width");
> > put_amf_double(pb, flv->video_par->width);
> > @@ -319,10 +321,12 @@ static void write_metadata(AVFormatContext *s,
> unsigned int ts)
> > metadata_count++;
> > }
> >
> > - put_amf_string(pb, "filesize");
> > - flv->filesize_offset = avio_tell(pb);
> > - put_amf_double(pb, 0); // delayed write
> > -
> > + if (!(flv->flags & FLV_LIVE_STREAM)) {
> > + put_amf_string(pb, "filesize");
> > + flv->filesize_offset = avio_tell(pb);
> > + put_amf_double(pb, 0); // delayed write
> > + metadata_count++
> > + }
> > put_amf_string(pb, "");
> > avio_w8(pb, AMF_END_OF_OBJECT);
> >
> > @@ -543,16 +547,19 @@ static int flv_write_trailer(AVFormatContext *s)
> >
> > file_size = avio_tell(pb);
> >
> > - /* update information */
> > - if (avio_seek(pb, flv->duration_offset, SEEK_SET) < 0)
> > - av_log(s, AV_LOG_WARNING, "Failed to update header with correct
> duration.\n");
> > - else
> > - put_amf_double(pb, flv->duration / (double)1000);
> > - if (avio_seek(pb, flv->filesize_offset, SEEK_SET) < 0)
> > - av_log(s, AV_LOG_WARNING, "Failed to update header with correct
> filesize.\n");
> > - else
> > - put_amf_double(pb, file_size);
> > -
> > + if (!(flv->flags & FLV_LIVE_STREAM)) {
> > + /* update information */
> > + if (avio_seek(pb, flv->duration_offset, SEEK_SET) < 0) {
> > + av_log(s, AV_LOG_WARNING, "Failed to update header with
> correct duration.\n");
> > + } else {
> > + put_amf_double(pb, flv->duration / (double)1000);
> > + }
> > + if (avio_seek(pb, flv->filesize_offset, SEEK_SET) < 0) {
> > + av_log(s, AV_LOG_WARNING, "Failed to update header with
> correct filesize.\n");
> > + } else {
> > + put_amf_double(pb, file_size);
> > + }
> > + }
> > avio_seek(pb, file_size, SEEK_SET);
> > return 0;
> > }
>
> > @@ -729,6 +736,7 @@ 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 = FLV_AAC_SEQ_HEADER_DETECT}, INT_MIN,
> INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "flvflags" },
> > { "no_sequence_end", "disable sequence end for FLV", 0,
> AV_OPT_TYPE_CONST, {.i64 = FLV_NO_SEQUENCE_END}, INT_MIN, INT_MAX,
> AV_OPT_FLAG_ENCODING_PARAM, "flvflags" },
> > + { "live_stream", "used for flv live stream mode", 0,
> AV_OPT_TYPE_CONST, {.i64 = FLV_LIVE_STREAM}, INT_MIN, INT_MAX,
> AV_OPT_FLAG_ENCODING_PARAM, "flvflags" },
> > { NULL },
>
> i may misunderstand the intend but you can use
> pb->seekable
> to identify if the output protocol supports seeking
> (a live stream where data was already sent could not support seeking)
>
> OTOH
> if the intend is to create files on seekable media that lack duration/
> filesize then the patch should be ok
>
> [...]
>
> --
> Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> Dictatorship naturally arises out of democracy, and the most aggravated
> form of tyranny and slavery out of the most extreme liberty. -- Plato
>
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>
> patch update
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