[FFmpeg-devel] [PATCH 0/3] Patch set to delay output live stream

[Tao Zhang]

Marton Balint <cus at passwd.hu> 于2020年4月30日周四 上午4:55写道：
>
>
>
> On Thu, 30 Apr 2020, Tao Zhang wrote:
>
> > Marton Balint <cus at passwd.hu> 于2020年4月30日周四 上午12:03写道：
> >>
> >>
> >>
> >> On Wed, 29 Apr 2020, leozhang wrote:
> >>
> >> > In some applications, it is required to add delay to live streaming.
> >>
> >> In what applications? And if you do this, why not run
> >>
> >> sleep 20; ffmpeg ....
> > In live streaming applications, someone wouldn't want broadcast what's
> > comming next immediately.
> > Sleep 20 then ffmpeg is not ok, because the stream is still
> > broadcasting immediately, and lost 20 seconds signal.
>
> So you want to buffer 20 seconds of input, and then start the output?
yes
>
> >>
> >> I don't see how this is useful at all.
> >>
> >> And what is -paced? What it is used for? Isn't it the same as using ffmpeg
> >> -re? You really should better explain your use case.
> > -re read the input, -paced write the output.
>
> But why do you want to delay every output packet?
By default, ffmpeg will output packets as fast as possible.
So I delay output every packet at native frame rate to simulate live stream.
>
> >>
> >> Regards,
> >> Marton
> >>
> >> > For example, you can add 20 seconds to rtmp stream with below command:
> >> > ffmpeg -i your_input_stream_address -c copy -map 0:a -map 0:v -f fifo -paced 1 -queue_size 6000000
> >> > -output_delay 20000000 -fifo_format flv rtmp://example.com/live/delayed_stream_name
> >> >
> >> > leozhang (3):
> >> >  avformat/fifo: add option to delay output
> >> >  avformat/fifo: add option to write packets in paced way
> >> >  doc/muxers: add command example how to delay output live stream
> >> >
> >> > doc/muxers.texi    | 17 +++++++++++++++++
> >> > libavformat/fifo.c | 26 ++++++++++++++++++++++++++
> >> > 2 files changed, 43 insertions(+)
> >> >
> >> > --
> >> > 1.8.3.1
> >> >
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