[mythtv-users] Is Wider better?

[Steve Hodge]

On 5/2/07, Jonathan Rogers <jonner at teegra.net> wrote:
>
> On Wed, 2007-05-02 at 11:45 +1200, Steve Hodge wrote:
> > On 5/2/07, Jonathan Rogers <jonner at teegra.net> wrote:
> >         On Tue, 2007-05-01 at 16:39 -0400, Cool Frood wrote:
> >         > Also, you needn't worry about capturing SD content with your
> >         PVR 350
> >         > to display on a widescreen.  MythTV does the Right Thing
> >         (TM) out of
> >         > the box.
> >
> >         Well, that's correct if you mean that MythTV records the video
> >         from the
> >         PVR-350 and then plays it back unmodified. If you record
> >         widescreen
> >         video using a PVR-350 or any NTSC (which is inherently 4:3)
> >         capture
> >         card, it must be letterboxed. If you then play that video back
> >         on a wide
> >         screen, it'll end up with pillarboxing in addition to the
> >         letterboxing.
> >
> > Is there letterboxing present in the original video? If there is then
> > it's not really widescreen video - it's 4:3 video that happens to
> > contain letterboxed widescreen content. True widescreen video is
> > recorded by the capture card without any letterboxing. It's not
> > recording in a 16:9 resolution, it's effectively compressed
> > horizontally (i.e. it's recorded as anamorphic widescreen video). If
> > you play it back on a 16:9 screen it will appear correctly without any
> > black bars.
>
> While anamorphic broadcast is possible, I don't know if it exists in
> NTSC countries; I certainly haven't seen it. I have seen many
> letterboxed programs on NTSC and ATSC 480i. Are you saying that MythTV
> would detect an anamorphic broadcast and display it correctly? MythDVD
> does display both 4:3 and 16:9 from the 720x480 DVD video, but that's
> part of the DVD spec and encoded in the MPEG stream.
>

What I'm saying is that the capture card doesn't care what the intended
aspect ratio of the video is, and neither does MythTV if you don't mess with
it. If the source video is full-frame widescreen (no letterboxing) then if
you display it with a widescreen aspect ratio no letterboxing or
pillarboxing will be introduced, regardless of the capture resolution and
aspect ratio. I'm in PAL-land rather than NTSC-land, but I don't see how
that matters. The only thing that matters is how the widescreen content is
broadcast (letterboxed or not).

In my setup I get widescreen content via a satellite set top box. The set
top box has been told that I have a widescreen tv, so that it doesn't
introduce any letterboxing of it's own. I then capture the output with Myth.
It's captured at (e.g.) 720x576 but it's capturing the full widescreen
frame. When I play it back on my plasma I get a proper widescreen picture
without letterboxing or pillarboxing and I don't need to mess with zoom
modes etc.

"Anamorphic" just means that the whole frame in the signal is filled even
though it's not the right aspect ratio. That's what I'm doing. But to use
anamorphic video you need to know what the intended aspect ratio is, so the
term usually implies flagging the intended aspect ratio somehow. AFAIK,
there's no standard way to do that in NTSC or PAL video.

Cheers,
Steve
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