[Gambas-user] Shell comand + FFMPEG from gambas how to

[Claus Dietrich]

Hi Martin

I had the same issue with parallel ffmpeg processes and finally decided 
to use native Gambas means (= GStreamer resources) for audio recording. 
I quickly put a class together for you with a little demo app which allows

- to choose the recording format (mp3, ogg or wav)

- to record from an alsa-device or to record a web audio stream (URL)

- to select an alsa-device (i.e. mike or monitor)

- to return a list of available alsa-devices as string-array

- to select the output directory (default=user home directory) where the 
audio file shall be saved as yyyy-mm-dd-hh-nn-ss_rec.<format>

With this class it should be possible to record the mike and monitor in 
parallel by using 2 instances. I tested the parallel recording of a web 
radio station stream and the mike of my Webcam.

If you didn't receive the demo project with this mail you can download 
it from my cloud: https://magentacloud.de/s/w45JHPTW7KJEwke

Hope that it works on your platform and that you can use it.

Regards

Claus


Am 20.10.23 um 23:44 schrieb Martín:
> Hi,
>
> If I do this in the terminal it works:
>
> ffmpeg -f pulse -i alsa_output.BLABLABLA.analog-stereo.monitor -i 
> <(arecord -f CD) -filter_complex amix -acodec libmp3lame output.mp3
>
> But if I do the same although Shell inside the gamabs code it doesn't 
> work.
>
> What I'm doing wrong? here is the sample code. The idea behind is 
> record 2 audio tracks at the same time one for the micro and other for 
> the internal audio output.
>
> Private hMicro As Process
> Private hSystem As Process
>
> Public Sub bRecord_Click()
>
>   If bRecord.Value Then
>     Record()
>   Else
>     Try hMicro.Kill
>     Try hSystem.Kill
>   Endif
>
> End
>
> Private Sub Record()
>
>   Dim sBase As String
>   Dim sMicro As String
>   Dim sSystem As String
>
>   sBase = Format(Now(), "yyyy_mm_dd_hhnnss")
>   sMicro = "ffmpeg -f pulse -i alsa_input.BLABLABLA.analog-stereo 
> -acodec libmp3lame " & sBase & "_micro.mp3"
>   sSystem = "ffmpeg -f pulse -i 
> alsa_output.BLABLABLA.analog-stereo.monitor -i <(arecord -f CD) 
> -filter_complex amix -acodec libmp3lame " & sBase & "_system.mp3"
>
>   hMicro = Shell sMicro For Read As "RMicro"
>   hSystem = Shell sSystem For Read As "RSystem"
>
> End
>
> I was thinking to sent the Shell command in a direct way, without 
> start a process first, but how I can kill the process, in the good 
> way,  later? Actually I use "killall ffmpeg"
>
> Second point: it is possible sent 2 commands with ffmpeg? because I 
> sent the first one and then the second one never occur.
>
>
>
> ----[ http://gambaswiki.org/wiki/doc/netiquette ]----
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