[mythtv-users] revo 3600, vdpau, bbc hd stutters

[Andre Newman]

On 1 Mar 2010, at 17:49, Greg Oliver wrote:

> On Mon, Mar 1, 2010 at 11:11 AM, Andre Newman <mythtv-list at dinkum.org.uk> wrote:
>> 
>> On 1 Mar 2010, at 15:58, Greg Oliver wrote:
>> 
>>> On Mon, Mar 1, 2010 at 9:41 AM, James Thorpe <james at tfxsoft.com> wrote:
>>>> 
>>>> 
>>>> On 01/03/2010 15:23, James Stembridge wrote:
>>>>> 
>>>>> On 1 March 2010 15:15, James Thorpe<james at tfxsoft.com>  wrote:
>>>>> 
>>>>>> 
>>>>>> One other thing to ask in this thread - I'm still seeing slight juddering
>>>>>> on
>>>>>> panning backgrounds (like it's missing frames, rather than stuttering -
>>>>>> the
>>>>>> audio is fine), I'm wondering if this has anything to do with screen
>>>>>> refresh
>>>>>> rates and video FPS etc - should I start reading about these?
>>>>>> 
>>>>> 
>>>>> If you're not already you'll want to use a 50hz video mode to get
>>>>> smooth pans with PAL content.
>>>>> 
>>>> 
>>>> That's probably it then - I think it's on default 60hz at the moment.
>>>>  Thanks for that - will try it out later.
>>> 
>>> Hmmm, I just did some searching for this as I am currently transcoding
>>> a lot of UK VHS tape rips to PAL.  It seems that some video players
>>> automagically change the refresh rate of the video out depending on
>>> the video being played.
>>> 
>>> I assuem mythtv does not do this, because on my revo frontends, I can
>>> see they are mismatched and nothing in the logs regarding it.  Since
>> 
>> It does in trunk or in JYA's .22-fixes, I'm using it now.
>> 
>> You need refresh rate set to any and separate modes for GUI & playback in the FE, now you know it exists google will find the details.
>> 
>>> the resolution is so low I am not really affected, but it would be a
>>> nice feature :)
>> 
>> The resolution make no difference, if the display and source frame rates don't match it's going to be juddery!
>> It's the sort of thing that a lot of people can tolerate but like banging your head against a wall, it's really nice when it stops ;-)
> 
> Much thanks!  I'll try it as soon as I get home tonight.

I also noticed that vdpau performance seems much better when the video frame rate and display rate are the same or multiples, 25 and 50, 30 and 60. I suspect that the mismatch in frame rate causes some big problems with the frame buffer handling.

I have one display that can only do 60hz, if I play 25fps or 50fps material on this display the performance is much worse than just the tearing and judder of the mismatch, everything else the same, just changing the display!

Andre



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