[FFmpeg-devel] ffmpeg g723

[Robert Watson]

Thanks, I'll give that a try [?]
Have you been able to maintain sync between audio & video using this method?
Robert

On Sat, Mar 10, 2012 at 3:28 PM, Zalewa PL <zalewapl at gmail.com> wrote:

> Hah! Bluecherry. I was suspecting that you are using their product.
> Thankfully I have some experience with this card and I can assure that it
> is possible to get the audio from this card using the 'decode-g72x' tool.
> Now that you have given us the ffmpeg command line that you use to create
> the video stream, here's what you have to do. Bash commands incoming:
>
> # Creates a named pipe
> mkfifo /tmp/audio_raw_stream
>
> # Extract audio data from the ALSA device. Decode it from g723 to PCM.
> # NOTE: Make sure this runs in background. You can't close this
> # pipeline or the streaming from ffmpeg will stop.
> arecord -Dplughw:1,0,1 -traw | decode-g72x -l -3>  /tmp/audio_raw_stream
>
> # ffmpeg now reads from the named pipe instead of the ALSA device
> # and decodes audio properly.
> ffmpeg -f s16le -acodec pcm_s16le -ac 1 -ar 8000 -i /tmp/audio_raw_stream
> -f v4l2 -i
>
> /dev/video1 -r 29.97 -b:v 800 -qmax 51 -async 1 -ar 11025 -ac 1 -ab 24k
> -acodec libmp3lame -vcodec libx264 -f flv rtmp://localhost/live/**
> livestream
>
> Trust me: unless I made a mistake in the parameters, this will work. I've
> been there. I've done that.
>
> Robert Watson wrote:
>
>  The card is manufactured by BlueCherry and has v4l2&  alsa opensource
>>
>> drivers.  This is what they said:
>>
>> Since Alsa currently doesn't have a format for G.723, the driver shows it
>> as unsigned 8-bit PCM audio.  We have sent a patch that was included in
>> alsa-kernel (hopefully getting synced to mainline soon). But this only
>> defines the correct format, it doesn't change the way you handle it at
>> all.
>>  You must convert G.723-24 (3-bit samples at 8khz) yourself.
>>
>> And, thanks for your help :)
>> Robert
>>
>> On Sat, Mar 10, 2012 at 2:32 PM, Benjamin Larsson<benjamin at southpole.se>*
>> *wrote:
>>
>>  On 03/09/2012 10:24 PM, Robert Watson wrote:
>>>
>>>  I was wondering if you could help with using ffmpeg to process the audio
>>>> input from a capture card.  The card has v4l2 and alsa drivers. The card
>>>> outputs G.723-24 (3-bit samples at 8khz).  Was the g723 code you wrote
>>>> committed into the ffmpeg core?  What command line should I use to
>>>> capture
>>>> the audio from the card?
>>>> Thanks, Robert
>>>>
>>>>  G.723 and G.723.1 is not the same. So it wont work. And probably the
>>> card
>>> doesn't output G723. Elaborate in detail and we might be able to help.
>>>
>>> MvH
>>> Benjamin Larsson
>>>
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