[mythtv] [mythtv-commits] Ticket #5552: AC3 passthrough causes accelerated playback on OSX 0.21 frontend

Craig Treleaven ctreleaven at cogeco.ca
Sat Jul 19 02:32:45 UTC 2008

At 12:37 AM -0400 7/18/08, Michael T. Dean wrote:
>On 07/17/2008 12:45 AM, MythTV wrote:
>>#5552: AC3 passthrough causes accelerated playback on OSX 0.21 frontend
>> When AC3 passthrough is selected on the OSX frontend, occasionally the
>> video an audio begin playing at an accelerated rate.  This usually happens
>> when the show is not bookmarked - i.e. playback starts from the beginning
>> of the file.  It never happens if AC3 passthrough is un-checked.
>> I've attached a log file.  The accelerated playback session begins at the
>> top of the file and ends at 21:29:24.  The normal playback session begins
>> immediately afterward at 21:29:25.  The most obvious difference between
>> the two is the appearance of a slew of " NVP: Video is x.xxxx frames
>> behind audio (too slow), dropping frame to catch up." messages once
>> playback begins in the first case.
>Are you sure the broadcaster isn't switching to 32kHz AC-3 at that location and your sound card is continuing to read data at 48kHz?  Most all computer-based sound cards work only with 48kHz AC-3.

I don't think this is the problem since the exact same portion of the recording will sometimes play fine and other times play in accelerated mode.


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