[FFmpeg-user] speex to ac3 in mkv

[Madovsky]

----- Original Message ----- 
From: "Carl Eugen Hoyos" <cehoyos at ag.or.at>
To: <ffmpeg-user at ffmpeg.org>
Sent: Sunday, February 03, 2013 10:15 AM
Subject: Re: [FFmpeg-user] speex to ac3 in mkv


> Madovsky <infos <at> madovsky.org> writes:
>
>> > Do the following also fail?
>> > $ ffmpeg -i rtmp://server/app/live -ar 48000 out.ac3
>> works
>
>> ffmpeg -i "rtmp://server/app/live live=1" -acodec ac3
>> -ar 48000 -b:a 128k -vcodec copy -y output.mkv
>
> Please find out what the difference is between the two commands.
>
> Does it fail if you add -ab 128 to the first command?
> Does the second work with -vn?
>
> Carl Eugen

the real problem is coming from the
fact I use a USB webcam as video source and a min jack PC input as audio 
source.
I confirm is all usb webcam I used with pc mic input cut the audio every 3/5 
sec
if I convert it together even with -vn
But the sound is not cut if I convert audio only.

Franck