[mythtv-users] flipping between interlaced and progressive source detection

[Scott]

On May 20, 2007, at 4:41 PM, Andy Burns wrote:

> On 20/05/2007 17:43, Scott wrote:
>
>> In the log below I mythtv flipping back and forth between progressive
>> and deinterlace modes during playback
>
> I see that on *one* DVB-T MUX inthe UK (MUX A which includes channel5)
> I've using kernel de-interlace (I'm surprised that this makes the
> picture look better as I have Radeon VGA->RGB SCART cable on a  
> 100Hz CRT
> so my display is interlaced, I'd expected de-interlacing to make
> interlaced material look worse until I tried it).

Hmm. This encouraged me to go double check my other OTA ATSC sources.  
I looked at recorded OTA ATSC prime-time HD content from ABC, NBC,  
CBS, and FOX. This was recorded via an HDHR using MythTV 0.21-p13344  
on Gentoo 2007.0.

ABC and FOX were correctly detected as 1280x720 59.9401 720  
Progressive. I saw no issues with shows on either station flipping  
between interlace and progressive frames over a 60 second period.

CBS and NBC were also correctly detected as 1920x1080 29.97 1088  
Interlaced. On multiple shows for both these stations I see flipping  
between interlace and progressive frames over a 60 second period.

So based on that quick check I assume I'm only going to seek  
interlace to progressive flipping on shows broadcast in 1080i.

> Myth doesn't seem to mind the switching, I do get backend crashes on
> that mux, but they don't seem to co-incide with the
> interlace/progressive switching.

Myth seems to handle it in the sense that it doesn't crash which is  
of course good :) But interlace artifacts are still visible during  
playback despite mythtv handling the format change. That makes  
streams that flip back and forth between interlace and progressive  
quite distracting to watch. I'm also not sure if this is a broadcast  
issue or if MythTV is either incorrectly or over aggressively  
detecting changes between interlace and progressive formats.

I'll try playing the streams back from mplayer and xine and see if  
they detect the same format changes. For the curious, my mythfrontend  
-v playback logs of each station are at http://donpoo.net/mythtv/ 
abc.txt , nbc.txt, cbs.txt, and fox.txt.

--
Scott