[FFmpeg-user] Questions about the concat video filter

Carl Eugen Hoyos ceffmpeg at gmail.com
Tue Jan 23 13:13:08 EET 2018

2018-01-23 11:09 GMT+01:00 Katherine Frances <knfrances at gmail.com>:

> Further, if the specs for the output streams are not explicitly set by the
> user, how does FFmpeg 'decide' what codec & options etc to use?

It tries hard...

> The docs say:
>> the filtering system will automatically select a common pixel format
>> for video streams, and a common sample format, sample rate and
>> channel layout for audio streams, but other settings, such as
>> resolution, must be converted explicitly by the user.
> but I don't find the wording isn't very clear. From my tests, it seems to
> default to something similar to the specs of the lower-quality input?

Please provide the command line you tested together with the
complete, uncut console output.
(The logic for selecting the pix_fmt cannot be clairvoyant, so
it cannot always find the best solution, the format filter exists.
Or are you not referring to the pix_fmt?)

Carl Eugen

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