Re: [Mlt-devel] flv - small sync, minutes of invalid
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From: Dan D. <da...@de...> - 2009-11-21 06:23:37
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On Tue, Sep 29, 2009 at 10:36 AM, Dan Dennedy <da...@de...> wrote: > On Mon, Sep 28, 2009 at 9:56 PM, Carl Karsten <ca...@pe...> wrote: >> On Mon, Sep 28, 2009 at 2:01 PM, Dan Dennedy <da...@de...> wrote: >>> On Sun, Sep 27, 2009 at 2:45 PM, Carl Karsten <ca...@pe...> wrote: >>>> I made a red/blue test flv, uploaded to blip, it plays perfectly: >>>> http://carlfk.blip.tv/file/2650272/ nothing new here, but if you >>>> want the details, I am setting the description to the melt and .mlt. >>>> I am not escaping the xml right, so it doesn't show up, but it's in >>>> the source. >>>> >>>> So I used the 'same thing' on a talk video. there is a slight sync >>>> problem about 3 seconds after 20 min, and >>> >>> I wonder if you are running into a problem with DV unlocked audio. You >>> can search to learn more, but Kino users had similar problems with >>> footage captured from certain devices. Then, I added some special >>> handling in Kino for this problem, and it resolved nearly all >>> complaints. So, to test this hypothesis, you can load the source DV >>> file into Kino, do no editing, and export it as a new DV file leaving >>> the resample audio checkbox enabled. This process converts it from >>> unlocked to locked and uses resampling to interpolate the missing PCM >>> data. Then, use the output of that in your mlt and script and see if >>> resolved it. >> >> Well, you are onto something. It did get rid of the audio sync >> problem when blip converted it. > > I am adding near the top of my MLT ToDo list, to work on better > support for unlocked DV audio. I can not jump on it right away, but it > is rather important. I am not sure I can make it automatic. I might > have to make it something like Replay Gain normalization. That means > you would do two passes: the first pass will report a correction value > that you supply to a filter for the second pass. > Carl, I just found and fixed a math bug that was causing the MLT avformat producer to drop some extra audio samples. This would account for some a/v sync drift as well as some crackling in the output. There will be a new release by the end of the month. -- +-DRD-+ |