[mythtv-users] What do I have to do to get HD working?

Kevin Kuphal kuphal at dls.net
Fri Apr 14 22:15:06 UTC 2006


Steven Adeff wrote:
> On 4/14/06, Kevin Kuphal <kuphal at dls.net> wrote:
>   
>> Michael T. Dean wrote:
>>     
>>> On 04/14/2006 05:36 PM, Kevin Kuphal wrote:
>>>
>>>       
>>>> Kevin Kuphal wrote:
>>>>
>>>>
>>>>         
>>>>> I'm about at my wits end.  I just purchased a P4 3.2ghz HT to do HDTV
>>>>> playback in software but no matter what I do, I get continual studdering
>>>>> and "Video X frames ahead of audio" on my HD playback material.  This
>>>>> happens on my MX4000 PCI video card system, my ATI 9100 IGP video card
>>>>> system, and my Unichrome Pro video card system.
>>>>>
>>>>> Everything I read said that a P4 3.2 is enough to do HD but nothing I do
>>>>> can get it to work.  I'm running the 2.6.15 smp kernel but that almost
>>>>> seems to make it worse.  With the non-smp on my Unichrome system it
>>>>> plays back but only at about 17-20 fps.  With the smp kernel, it does
>>>>> the 29-30 but jumps and skips complaining about the video ahead of audio.
>>>>>
>>>>> Please, anyone have any help?
>>>>>
>>>>>           
>>>> And a little more, I can duplicate the 17-20fps setting when I set my
>>>> audio device to something wrong or if I disable audio in the BIOS.  Is
>>>> this possible some kind of ALSA problem maybe?
>>>>
>>>>
>>>>         
>>> Hmmm.  20fps is 2/3 of 30fps and 32kHz is 2/3 of 48kHz....  Perhaps your
>>> ALSA device is playing a 48kHz stream (which you're likely to see in
>>> HDTV) at 32kHz?
>>>
>>> What audio device are you using for playback?  Assuming you have ALSA
>>> 1.0.9 or above, try "ALSA:default", which will use the "plug" conversion
>>> plugin to automatically convert sample, rate, and format as required for
>>> your sound card.
>>>
>>>       
>> Normally I use ALSA:spdif but I tried ALSA:default with the same
>> results.  If I play it with mplayer it reports that the audio is
>>
>> Opening audio decoder: [liba52] AC3 decoding with liba52
>> Using SSE optimized IMDCT transform
>> AC3: 2.0 (stereo)  48000 Hz  384.0 kbit/s
>> Using MMX optimized resampler
>> AUDIO: 48000 Hz, 2 ch, s16le, 384.0 kbit/25.00% (ratio: 48000->192000)
>> Selected audio codec: [a52] afm:liba52 (AC3-liba52)
>>
>> I don't have any .asoundrc (never needed it).  The system I'm working on
>> now is the Unichrome Pro system using the internal snd_via82xx driver.
>> I have a Turtle Beach riviera I could throw in there if I need to but
>> the results have been the same no matter what I've tried
>>     
>
> so does it play right in mplayer?
>
>   
Not really, it studders quite a bit and reports the system isn't capably 
of doing playback (this is with just a straight mplayer <filename>).  
Oddly, I can get -vo xvmc and -vf ffmpeg12mc working fine with mplayer 
but can't get Myth to do it.  Of course, that's not why I bought the P4...

Kevin


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