[mythtv-users] Recordings Playback too fast on Frontend, fine on Backend

jk90090 jk90090 at gmail.com
Mon Mar 2 20:09:27 UTC 2009

Michael T. Dean wrote:
> First, no need to bump your post after 53 minutes--or, more likely, 
> what you missed was--yes, your post went through.  <rant>Thanks to 
> gmail's "it's not e-mail, it's g-mail, so we do things differently" 
> interface, you don't get to see your messages until someone replies to 
> them.  (How wonderful of them to invent a replacement for 
> e-mail...)</rant>  Please always check the archives before re-sending 
> a post.  http://www.gossamer-threads.com/lists/mythtv/ may take many 
> (up to 12) hours to be updated to include new posts; whereas, 
> http://mythtv.org/pipermail/mythtv-users/ is updated "immediately."
First off, I got back an "undelivered mail" back from the mythtv mail 
system ~50 minutes after my original post, indicating a mail forwarding 
loop for mythtv-users, hence the repost. 
> Answers inline...
> On 03/01/2009 12:12 PM, jk90090 wrote:
>> Just replaced my OTA tuners with an HDHomerun, pulling video from 
>> QAM.  Recordings happen as expected, but when I go to playback the 
>> recordings, some (FOX it seems) playback tooo fast, as if I've 
>> increased the playback speed, and the video & audio don't sync.
> This is one or both of 2 configuration issues.  Make sure you do /not/ 
> enable the "experimental" (= "do /not/ use this setting, it doesn't 
> work because the video in the real world is all broken") setting:
> Use video as timebase
> Use the video as the timebase and warp the audio to keep it in sync. 
> (Experimental)
> and make sure you configure your audio subsystem (outside of Myth) to 
> enable playback of audio with sample rates other than 48kHz.  You may 
> be playing back a recording with 32kHz audio, but your sound card is 
> slurping it up at 48kHz, making it play back faster and making voices 
> sound "like chipmunks."
> See http://www.mythtv.org/wiki/index.php/Configuring_Digital_Sound 
> (and try to ignore all the completely wrong information on the page) 
> for more info.  (And note that if you value your time, it may be 
> cheaper to just get a new sound card that sets up more easily.  The 
> Turtle Beach Riviera is one of the favorites on this list.)
Everything checks out on this front too.  I'm trying turning the various 
settings on and off in different combinations to no avail.  I'll recheck 
the the settings in the DB settings table.

>>   Also of note is that the recording time length (say 59:32) is half 
>> of what it should be (say 30:21).
> That's "normal."  It's only a display-related bug whose fix requires a 
> lot of work, so is not high priority, but occasionally (over the 
> years) some of the patches that are committed move us a small step 
> forward toward a proper fix.  It should be fixed around MythTV 1.0 or 
> so.  ;)
Ha, ok.  It seems these recordings with the shortened time display 
(first time I'm seeing this happen in over 2 years of use) are also the 
ones playing higher-speed.

>>   The backend plays the recordings fine (though also shows the time 
>> length incorrect, and seconds take twice as long to tick by), and VLC 
>> will play the recordings fine on my Vista PC.  Ideas? 
> The backend's audio is probably properly configured.
Same settings.  *Shrug*

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