MythTV incorrectly detects interlaced stream on progressive content

[Cory Maccarrone]

Binary package hint: mythtv

When playing videos using MythVideo on my local hard drive, the situation frequently occurs that mythtv will set the video scan to "Interlaced" and lock it there, causing frame stuttering and flickering. This is in a progressive stream.

I've managed to narrow down what's happening, and it seems whenever the stream switches from 24000/1001 to 30000/1001 frames, myth thinks the stream is interlaced. Problem is, when the frame rate goes back, myth never sets the video scan back to progressive, so I end up with deinterlacing applied to a progressive stream.

I made a quick patch to the source code that for me fixes the problem:

--- libs/libmythtv/NuppelVideoPlayer.cpp-orig 2010-04-17 12:38:32.799073334 -0700
+++ libs/libmythtv/NuppelVideoPlayer.cpp 2010-04-17 12:38:43.867081365 -0700
@@ -989,7 +989,6 @@
             {
                 VERBOSE(VB_PLAYBACK, LOC + "Locking scan to Interlaced.");
                 SetScanType(kScan_Interlaced);
- return;
             }
         }
         m_scan_tracker++;

However, this change was implemented in revision 22121 of mythtv in response to this mailing list post:

http://mythtv.org/pipermail/mythtv-dev/2009-October/066439.html

So, I don't imagine this is a good fix. Better would be to fix mythtv's handling of frame rate changes.

For reference, this is on the latest beta release of Mythbuntu 10.04.

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: libmyth-0.23-0 0.23.0+fixes24158-0ubuntu1
ProcVersionSignature: Ubuntu 2.6.32-19.28-generic 2.6.32.10+drm33.1
Uname: Linux 2.6.32-19-generic i686
NonfreeKernelModules: nvidia
Architecture: i386
Date: Sat Apr 17 12:32:34 2010
InstallationMedia: Mythbuntu 10.04 "Lucid Lynx" - Beta i386 (20100318)
Installed_mythplugins-dbg: 0.0
Installed_mythtv-dbg: 0.0
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: mythtv

[Thomas Mashos (tgm4883)]

We really do appreciate you opening this ticket to help improve Mythbuntu, but it needs to be closed for a number of reasons. The biggest one is that we have turned our efforts to a newer version. Could you please verify if this issue still exists in the latest version?

Please do not let the closing of this ticket dissuade you from opening a new ticket if this (or any other) problem occurs with the newer versions.