[mythtv-users] Audio Sync and Choppy Video
Michael T. Dean
mtdean at thirdcontact.com
Wed Apr 11 13:23:31 UTC 2007
On 04/11/2007 03:16 AM, Andrew Prock wrote:
> On Tue, 10 Apr 2007, Brad Fuller wrote:
>> Andrew Prock wrote:
>>> On Tue, 10 Apr 2007, Michael T. Dean wrote:
>>>> On 04/10/2007 06:21 PM, Andrew Prock wrote:
>>>>> So after six months of running MythTV on my machine
>>>>> and suffering through choppy playback on most recordings,
>>>>> I finally found an option which essentially eliminates it for
>>>>> The option is "-autosync 30" for mplayer.
>>>>> Unfortunatly, there doesn't seem to be an equivalent option
>>>>> for the Internal player. Is there someplace that I haven't
>>>>> looked or is this feature not available for MythTV's Internal
>>>> Of course, you could just get a working sound card... ;)
>>> I'd love to. I've already got onboard sound working, but
>>> aparently you're suggesting it's not good enough? In all
>>> my research about equipment, I never found any real info
>>> about soundcards.
>> What kind of info?
> Specifically, what are the issues relating to sound
> cards and audio/video sync, and how will a specific
> sound card resolve that issue?
> With the discovery of the autosync solution for
> mplayer, I think that the choppy video problem
> isn't a video problem, but a sync problem. It
> doesn't look like there's good A/V sync in MythTV,
> so will buying a sound card resolve that, or will
> it just add another 2-20 hours of opportunity cost?
# man mplayer
Gradually adjusts the A/V sync based on audio delay measure-
ments. ... Try -autosync 30 to
smooth out problems with sound drivers which do not implement a
perfect audio delay measurement. ...
So if your sound card/drivers did proper audio delay measurements...
Your buying a new sound card is much less expensive than the time for a
developer (whose sound card already works) to implement this A/V sync
So, IMHO, you have two options: a) buy a new sound card, or b) port the
MPlayer code over into MythTV and post a patch for consideration (with
specific information showing why it's beneficial and worth creating a
new configuration option).
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