How to get ffmpeg output when youtube-dl uses it as downloader?

[abvalyn]

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Question

TL;DR Is there a way to see ffmpeg output when youtube-dl uses it as downloader?

Longer:

It was available for some time (e.g. in release 2021.04.07 for pornhub-m3u8 videos and then logic was changed and output was hidden by this commit. The example of such an output might be found here).

It shows useful warnings/errors (like "HTTP error 429 Too Many Requests" and "HTTP error 403 Forbidden", etc.) which might be ignored by youtube-dl itself. Youtube-dl might show successful download when some peaces of video are actually not downloaded. I'd like to get at least ffmpeg logs to avoid such situations.

[dirkf]

Try --verbose/-v.

If that's too much, try --external-downloader-args '-v 32', or 24 or 16 instead of 32 for still less (Windows: '' -> "").

If that's not enough, try --external-downloader-args '-v 48'.

Only the ffmpeg authors can explain why their program that does a lot of multiplication elsewhere was unable to turn numbers like 1, 2, 3, 4, ... into 8, 16, 24, 32, ... (though there are text alternatives).

[abvalyn]

Thanks for your reply.

I investigated a little more. It looks like last version of youtube-dl with --verbose flag actually shows HTTP-errors if they lead to fragment fail and hide them if e.g. 6 out of 10 attempts are failed.