Tom Metro wrote:
> Tom Metro wrote:
>>> ...and whether the "harddup video filter" documented here:
>>> http://www.mplayerhq.hu/DOCS/HTML/en/menc-feat-dvd-mpeg4.html#menc-feat-dvd-mpeg4-muxing-filter-issues
>>>
>>> helps...
>> I'm not entirely convinced that this filter even did anything, and that 
>> there was a difference from the prior transcodes I did with no audio 
>> sync options. One thing that makes me skeptical is that I still saw the 
>> warnings about skipped frames (same as with no options), and never a 
>> warning about a frame being added. I also am not sure that mencoder 
>> applies video filters when you are using the copy codec.
>>
>> I'll have to test more files, and see if there is any difference in the 
>> file size between a run with "-vf harddup" and a run without. In theory, 
>> they should be different.
> 
> My test showed:
> 
> 683241472 2010-04-11 20:13 2061_20100408233000-hard.mpg
> 683241472 2010-04-11 20:49 2061_20100408233000.mpg
> 
> Identical file size suggests the filter does nothing. I couldn't find 
> anything in the man page or user guide explaining whether filters 
> applied to the 'copy' codec, but the built-in help text says:
> 
> % mencoder -ovc help
> Available codecs:
>     copy     - frame copy, without re-encoding. Doesn't work with filters.
> 
> So that answers that question.
> 
> I don't entirely understand why this is the case, as mencoder should 
> still be dissecting the stream enough to be able to add frames. This is 
> implied by its warnings that it is dropping frames.
> 
> While doing a video transcode should correct this, I don't know whether 
> the loss in quality and time needed for the transcode warrant the slight 
> improvement in sync.
> 
> I also experimented with -noskip, -audio-density, -audio-preload, and 
> dropping the audio bitrate, and none has produced any better results.
> 
> I guess I'll have to post to the mencoder user's list to see if someone 
> with an understanding of mencoder internals can offer advice.
> 
>   -Tom


I have a single channel that started being way out of sync, all of the 
other channels that I have seem to stay in sync (or at least around .1 
seconds off or so), but this one gets 30+ seconds out of sync...and 
that is with a full video+audio trancode.

Not sure of the cause, I am going to have to record a sample and keep 
it and see why it fails.   That is one of the reason my script was so 
large, each broadcaster seems to put out different audio+video stream, 
so you need lots of special cases, there are probably a few more cases 
that I have not seen once someone includes in the various cable 
broadcasters that reformat into their own bizarre streams and resolutions.

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