[Kdenlive-devel] DV rendering seems to be broken for PAL-WIDE

[Dan Dennedy]

On Thu, Dec 25, 2008 at 7:02 AM, Jean-Michel Pouré <jm at poure.com> wrote:
> Dear Friends,
>
> DV rendering seems to be broken, at least for PAL-WIDE.
>
> To reproduce:
> * Download http://www.kdenlive.org/videos/rawdvpalwide-test-1.dv
>
> * Create a PAL WIDE project.
>
> * Export profiles are not WIDE.
>
> So create a custom profile:
>
> Extension : dv
> Parameters: f=dv vcodec=dvvideo pix_fmt=yuv420p acodec=pcm_s16le
>
> Now export. The resulting file has a wrong DAR. It is normal PAL, not
> PAL-WIDE.

This is fixed now in MLT.

> The following FFmpeg command produces exactly the same croped file:
> ffmpeg -i rawdvpalwide-test-1.dv -pix_fmt yuv420p test.dv

This could be considered a bug, but the whole area around correct
sample aspect ratio for DV, DVD and similar formats is rather nasty.
Basically, the sample aspect ratio FFmpeg uses for DV is not
mathmetically convertable to display ratio using the resolution like
every other format. This is all really messy, and the details are
tiresome and unpleasant for me to go into on a Christmas night. But
basically, the FFmpeg DV decoder uses these more proper ratios, but
the encoder, being generic and agnostic to its source uses a simple
mathematical formula to determine if it is wide. Well, the proper wide
PAL sample aspect ratio fails this test! I am able to work around it
in MLT.

-- 
+-DRD-+