[FFmpeg-user] Setting up a watch folder to encode adaptive bit rate videos

James Darnley james.darnley at gmail.com
Tue Nov 3 14:17:06 CET 2015

On 2015-11-03 12:57, Christian Ebert wrote:
> * James Darnley on Tuesday, November 03, 2015 at 01:29:43 +0100
>> libx264 definitely supports changing resolution between first and later
>> passes.
> Also when then second pass involves a change in profile and/or
> level, meaning change of frame types?
>> It also determines frame types in the first pass.
> So, only when the same profile and level and frame related
> settings are the same, I assume.

If you change settings so that the stats file and the current settings
cannot be resolved then I would hope that there is an error rather than
continuing to do some unknown thing.  Last I remember is that the second
pass doesn't run frame type decision at all.

E.g. I would hope that using a stats file which has B-frames and asking
for main profile would result in an error.

(Why you would ask for main profile these days is beyond me.)

> otoh without slow-firstpass for instance the reduction to ref=1
> might affect already frame types?

It been a long time since I looked into all this but I recall that few
options make a difference to frame types.  They are decided in the
lookahead.  I don't think that reference frames were one of the settings
that affects it.

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