[FFmpeg-user] Video/Audio speed reduces when recording started

Thilo Borgmann thilo.borgmann at mail.de
Tue Aug 22 13:21:16 EEST 2017


> I have connected my bluetooth device to my mac (AirPods) and try to record
> the mic as well as a running youtube video by running the command:
> ffmpeg -f avfoundation -video_size 640x480 -framerate 30
> -video_device_index  0 -i ":2" outsf.avi

please send the complete uncut console output.

> However when I start the recording I see 2 problems:
> 1. The sound thats coming in the airpods has gaps - like it stops for a
> couple of milli seconds
> 2. The speed of the running youtube autio/video reduces to 1/2 or even lower
> What am I doing wrong?
> If I use the built-in audio and mic, the recording runs fine without any
> problem.

> I am using the soundflower 2ch to capture and redirect the output to the
> recording input, and have created the aggregate devices and multi-output
> devices.

Running on built-in inputs indicates that either AirPods or soundflower is problematic. IIRC I've got a report about problems with soundflower in the past and according to https://rogueamoeba.com/freebies/soundflower/ there is not much hope that this will improve. You might want to check out the alternative mentioned on the website. Please report back if that changes anything for you.

If that does not help you, please make a sample recorded with built-in inputs and one sample recorded with your current setup available to download.
Also add the uncut console output for both samples somewhere.

Thanks for reporting in,

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