[FFmpeg-user] multiple live rtmp inputs latency

Madovsky infos at madovsky.org
Mon Feb 4 00:25:43 CET 2013

----- Original Message ----- 
From: "Carl Eugen Hoyos" <cehoyos at ag.or.at>
To: <ffmpeg-user at ffmpeg.org>
Sent: Sunday, February 03, 2013 5:00 PM
Subject: Re: [FFmpeg-user] multiple live rtmp inputs latency

> Madovsky <infos <at> madovsky.org> writes:
>> I just updated from git 10 mn ago and now the 2 live rtmp
>> are well syncrhonized as long as the audio from second
> input is not "amerge" nor "pan" with filter_complex.
> This sounds as if the problem should also be reproducible
> with files or am I wrong?
> Carl Eugen

Sorry Carl I made so many test last days (maybe a thousand)
 I think I mixed up some rersults

Now I splitted the tests in 2 for finest results and less confusion.

2 live streaming from one USB cam (in as2/3 publisher 1 NetConnection, 2 
containing 1 speex in each channel from the same device (builtin pc mic)

video test:
from a player I can see no latency at all between the live streams 
(audio/video ok)
but if I overlay them in any format the video latency is occured
ffmpeg -i "rtmp://server/app/live1 live=1" -i "rtmp://server/app/live2 
live=1"  -i back.png -filter_complex 
[base][2:0]overlay=0:main_h-20"  -an -vcodec flv -tune 
zerolatency -shortest -y output.flv

audio test:
same result as video. there are about 2.4 second latency between the 2 audio 
ffmpeg -i "rtmp://server/app/live1 live=1" -i "rtmp://server/app/live2 
live=1" -filter_complex "[0:1][1:1]amerge" -ac 1 -acodec libspeex -vn -tune 
zerolatency -shortest -y output.flv


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