[mythtv] Re:[PATCH] MPEG4 interlaced DCT & ME

Mark Frey markfrey at fastmail.fm
Sat Mar 13 17:33:52 EST 2004

I actually tried this patch when you first posted it, and it caused problems for me.

It increases processor usage for me by about 10-15%. It also causes a problem for me when starting up a recording (either starting live TV or when a recording starts). I sometimes get either a blank or "crawling" green screen. If I escape out of live tv and reenter it will eventually work, but of course I can't do that for recordings, and the first two I tried with these flags wound up being all green. This effect seems worse at lower bitrates. I'm using a Hauppauge WinTV 401 card (bt878). I'm also using V4L2 on a 2.6.3 kernel. I havent' tried the DCT flag independent of the ME flag yet, so I don't know if that would change the behavior for me.

>Hash: SHA1 
>Not sure if anyone spotted this patch, so a quick re-post: 
>On Tue, 9 Mar 2004, Isaac Richards wrote: 
>> On Tuesday 09 March 2004 03:53 pm, D Banerjee wrote: 
>> > Looks like we don't ever set CODEC_FLAG_INTERLACED_DCT or 
>> > CODEC_FLAG_INTERLACED_ME, but we are asking v4l2 for interlaced video. Is 
>> > this codec option being set elsewhere, or is it defaulting to interlaced? 
>> They're not there because they're both relatively recent flags in libavcodec, 
>> and I have never gotten around to testing how they effect quality and cpu 
>> usage. I'd be happy to add them if someone wants to look into that. 
>I wrote a patch a couple of weeks ago which I never got around to 
>submitting to the list, so I've attached it to this mail. It adds 
>tickboxes to the recording profiles which allow you to turn on the 
>interlaced DCT and ME options. I've been running it for the past 2 or 3 
>weeks with no problems (and no noticable increase or decrease in CPU 
>- - -- 
>- Steve http://www.nexusuk.org/ 
>Servatis a periculum, servatis a maleficum - Whisper, Evanescence 
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