[mythtv-users] re: choppy HD playback
John Sturgeon
john at sturgeonfamily.com
Wed Apr 21 11:53:25 EDT 2004
HI Brandon,
I'm wondering what you use to transcode your HD nuv files. Do you use
nuvexport, and if so what output format and settings do you use. I too
have a 2600+ and find 1080i to be 'less than optimal'.
Thanks,
--
John Sturgeon <><
Brandon Beattie wrote:
>Scott,
>
> I run an amd 2600+, I have problems running 1080i also. It will run
>fine if you turn of de-interlacing in the tv playback setup. However,
>the current algorithm for deinterlacing does not work well for high
>resolution files (Such as HD). At one point someone mentioned they were
>going to write a couple new deinterlacing algorithms to help, but that
>was a couple months ago. In the future, your 2500+ /may/ be okay. Most
>of the problem with HD streams is not really myth, but the X server. X
>is very poor when trying to display HD. (Not to mention it does not do
>a good job at syncing frames and keeping video smooth). When X is
>re-written (as there is a project going on for this now) it will work
>much better and will have true v-blank support. You should be able to
>watch 1080i on about a 1.7Ghz (This is what is required for windows that
>properly handles v-blank and has a good de-interlacing for HD I've been
>told). I personally recommend a P4 3.0Ghz with HT. It almost doubles
>your speed in regards to decoding HDTV and letting X suck up more
>CPU cycles than it should really need. The same stream on my 2600+ that
>maxes out my CPU and is basically unwatchable, takes about 70% CPU usage
>on a P4 3.2Ghz with HT. Other possible issues are the way mythtv scales
>video that is not native display size. Right now, I (try to) transcode
>all programs to 1024x576 (my native display size). Transcoding is a bit
>broken right now, but this takes care of things for me, but I don't
>watch livetv, and this also saves disk space. I also recommend a higher
>CPU because if you want to transcode, the border line is not good. Even
>when watching transcoded shows, if the transcoder kicks in I can notice
>it on my 2600+, the P4's with HT don't appear to be noticible. I'm
>waiting a bit to see if I can't find a dual P4 MB for cheap in a half
>year and I'll pick up one of those for my mythbox. Transcoder can use 1
>processor, and my dvd, or livetv (If I do use it) can use the other.
>
>That's my $.02
>
>--Brandon
>
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