[mythtv-users] Transcoding and aspect ratio (DVB-T)

[Nick]

On 26/02/06, Ian Grant <mailinglists at iangrant.me.uk> wrote:
> Hi all,
>
> I noticed a previous question on this topic, but couldn't find any answers.
> I record in MPEG2 from DVB-T. The files are usually 720x576, and usually
> with a 16:9 aspect ratio (sometimes 4:3 programmes are transmitted in
> 4:3 but more often in 16:9 with side bars, it seems).
> When I transcode them to MPEG4, the aspect ratio is reset to 4:3 -- it
> seems that mythtranscode is not setting the aspect ratio correctly in
> the transcoded nuv file, or perhaps is not extracting it properly from
> the TS MPEG2, or both.

I don't have a solution for mythtranscode, but I'm quite sure that
MPEG4 does not support embedding the AR in the video, as is the case
with MPEG2. When I want to convert DVB-T recordings to MPEG4 I do it
in VirtualDub and crop/resize to either WS 16:9 (typically 640x360) or
FS 4:3 (640x480) 'square pixel' resolutions. Some players (like Media
Player Classic) allow altering the aspect ratio of AVI files during
playback, but I think it is up to player to be told how to display the
file, whereas an MPEG2 file will automatically switch based on the
embedded AR of the video.

Nick