Re: ffmpeg and alsa/pulseaudio

[Ekaitz Zarraga]

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Friday, May 29, 2020 3:34 AM, Leo Famulari <leo@famulari.name> wrote:

> On Tue, Apr 07, 2020 at 11:54:35AM +0000, Ekaitz Zarraga wrote:
>
> > Hi,
> > I'm trying to make a screencast with ffmpeg and I'm having issues.
> > I had a screen recording script on the past, based on alsa, but it's not 
> > working in guix because it looks like ffmpeg wasn't compiled with alsa. Is 
> > that true? Is there something I missing to activate alsa on ffmpeg?
> > This is the command I was running:
> > ffmpeg \
> > -y -f x11grab -draw_mouse 1 -framerate 25 -video_size 1920x1080 -i $DISPLAY 
> > \
> > -f alsa -ac 2 -i default \
> > -pix_fmt yuv420p -c:v libx264 -preset veryfast \
> > -c:a libmp3lame -q:v 1 -s 1920x1080 -f matroska \
> > output.mkv
>
> I tried this but it failed with ":0: Invalid argument". That's the
> $DISPLAY variable. Do you know what it should say?

Hi Leo,

Thanks for the answer. I have :1 in DISPLAY and it's not failing because of 
that.

More on the issue: I had to use a different microphone for this just because of 
this issue. Looks like when I use a USB microphone and use pulseaudio engine it 
breaks somehow and records audio with wrong timestamps. An analog microphone 
works well.
With alsa I found a working configuration but it doesn't work :(

Thanks!