[mythtv-users] Scaling HD output

[Daniel Kristjansson]

On Mon, 2005-11-07 at 21:37 -0500, Dave wrote:
> > [1920x1088 vs. 1920x1080 for 1080i broadcasts]
> > Thanks, Seth
> I'm not 100% sure on the details, but I believe the extra 8 lines are
> overscan or other data (ie, not picture data).  I had the same issue
> with the resolutions not being switched.  You need to update the
> database to look for 1088 instead of 1080.  For example:

The extra 8 lines are not used for any data. The reason for them has
to do with MPEG-2 which needs resolutions to be multiples of 16, so
1080 is 8 lines too short. The reason for using it rather than the more
efficient 1088 for the resolution, is because it gives you an aspect
ratio of exactly 16/9 with square pixels.

Anyway the reason it gives us problems is because some broadcasters
tell MythTV that the resolution is 1920x1088 in the MPEG sequence
header and others report a resolution of 1920x1080. I don't believe
ATSC specifies which one is correct. We have a special case in
VideoOutput::Init() which changes any reported resolution of 1920x1088
to 1920x1080.

I believe the problem is that ResizeForVideo() uses the reported
resolution, not the hacked 1088->1080 resolution. I'll try to fix
this tonight...

-- Daniel