Re: Restore/set aspect ratio header in DV files?

Op dinsdag 26-05-2009 om 09:52 uur [tijdzone -0700], schreef Dan
Dennedy:
> On Tue, May 26, 2009 at 5:57 AM, Richard Rasker <[email protected]> wrote:

[snip Cinelerra messes up DV aspect ratio]

> > The basic question is simple: is there a way to force a 16:9 aspect
> > ratio onto a DV file -- iow: set the 16:9 aspect ratio header in the DV
> > file? Kino's Edit -> Preferences -> Defaults offer an aspect ratio
> > setting, but this is apparently overridden by the project/video file, so
> > Cinelerra's faulty header settings are not changed.
> >
> 
> It depends upon your definition of easy and what you are willing to
> sacrifice. :-) I see 2 ways: transcode with ffmpeg using the -aspect
> option, or write a little C program using libdv to change the
> metadata. With the transcode you will lose a little quality, but not
> much, and it takes time and space. And at least you can use the
> -threads option to make it faster.

OK, the ffmpeg command seems to work fine already, thanks a lot!

About the C program: I'd really like that solution, as it sounds much
cleaner and faster than transcoding. But alas, I'm not really a
proficient C programmer, to put it mildly. Nevertheless, I'd like to
give it a serious try, if someone can start the wool on for me, as it
were :-) And perhaps I could even supply a fix for Cinelerra ...

So what DV metadata would need changing, exactly? Is this metadata
contained in every frame, or is it just one header somewhere at the
start of the DV file? And could you name an example of a source file
which performs a similar operation on a DV file?

But if you think I'm a little over-enthusiastic, I can live with the
ffmpeg solution, no problem -- so far, I can see no difference in
quality between the input and output files.

Anyway, thanks again, best regards,

Richard Rasker


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