[FFmpeg-user] Changing DAR ?

[Ronald F. Guilmette]

In message <068B1B8693FF41FC93C7864BCE24927B at HPKANTOOR>, 
"Bouke \(VideoToolShed\)" <bouke at videotoolshed.com> wrote:

>
>----- Original Message ----- 
>From: "Ronald F. Guilmette" <rfg at tristatelogic.com>
>>
>> So, just to be sure now, please confirm that it _is_ indeed the case that
>> "-vcodec copy" is incompatible with the "-vf <anything>" option, yes?
>
>Perhaps i'm missing the point, but -vcodec copy -aspect 16:9 does work fine.
>No need for -vf if you just want to change DAR.

I agree that that combination _does_ in fact work for some subset of
all of the video formats that ffmpeg handles... although it appeared
to me that it does not work for all.  I may be wrong about that, but
at this moment I don't think so.  I will need to do more experiments,
I guess, and report hard facts and findings.

As regards to the point which you may or may not be missing, as I said,
as of 2.0.1, ffmpeg appears to allow both -vcodec copy and also -vf options
to be used together, and it just silently ignores one of those, which in
my opinion is rather entirely sub-optimal.

Also, I believe that there may be cases where using -vf and setsar or
setdar may cause unexpected effects, specifically on the aspect ratio
that is _not_ being changed.  But I have to get in and dig around on the
mediainfo sources and try to find out if some of the things it is telling
me may be slightly less than true, at least for some video formats.  If
so, then it is really mediainfo's fault for printing misleading output.


Regards,
rfg