[mythtv] HDTV patches

[Daniel Thor Kristjansson]

 The whole set of the latest patches is available here:
  http://www.mrl.nyu.edu/~danielk/mythtv/all-patches-v1.tbz

When I apply all of them, I do it in this order: xvmc-deinterlace,
xvmc-idct, hdtv-signalcheck, hdtv-recorder, xvmc-efficiency. Of the
non-patch files, XvMCSurfaceTypes.h is required for xvmc-idct, and the
rest are used by the recorder patch; they all go in libs/libmythtv.

*

The signal check patch is fairly simple, I made two changes to the
last version, one is to support both inputs throughout, and the
other is to use v4l2 if available. The second change is for the new
2.6.6 pcHDTV drivers, but it doesn't break the old driver since it does
not support v4l2.

*

The idct patch is a little more complicated. First, it adds
XvMCSurfaceTypes.h which descripes a XvMC port. XvMCSurfaceTypes.h also
includes a couple find functions that let you locate a surface that
supports the chroma, mpeg version, idct/mv, resolution and subsurface
resolution. One locates a surface on a particular port that
XvMCSurfaceTypes.h describes and the other is a static function that
looks at a range of ports you specify on a particular display and
adaptor. These find functions let you simplify VideoOutputXvMC::Init().
I've also changed this function so it does also tries to find an IDCT
capable surface first on a particular display and then try to find an MC
capable surface. The old code didn't care which it got, so in practice
it always got an MC only capable surface.

I've added a method to VideoOutputXvMC called hasIDCTAcceleration()
which tells the caller if the XvMC surface supports IDCT Acceleration.
This lets NuppelVideoPlayer tell the AvFormatDecoder what kind of pixel
format to use. This is done in InitVideo() right after
VideoOutputXvMC::Init() is called.

AvFormatDecoder in turn has a method called SetPixelFormat() which
associates a pixel format with the video codecs in it's codec context.
It also has a function that returns this pixelformat when given the
context. This function is passed to the encoder when an XvMC decoder is
created so that when it begins decoding the stream it will be told to
use whatever pixelformat was specified by SetPixelFormat() when the XvMC
surface was created (The XvMC surface is created after the avdecoder,
but before te avdecoder calls getFormat(). The other small change I made
was to use the ffmpeg defines for the error_concealment and idct_algo
for clarity, to remove the setting of rate_emu, which doesn't do
anything, and add the setting of enc->error_rate with a comment. Setting
enc->error_rate to a higher value will allow broken streams to play, but
adds junk to correct streams, when the recording patches are more
complete I should be able to detect broken streams and set this
accordingly.

*

I'll describe the other patches in later e-mails. But I'll note
that xvmc-deinterlace is a poor man's deinterlacer which may reduce
playback quality and hdtv-recorder is still experimental and produces a
lot of printf noise.

-- Daniel