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Old 23rd July 2018, 02:10   #3127  |  Link
manolito
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Join Date: Sep 2003
Location: Berlin, Germany
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Quote:
Originally Posted by MrC View Post
About the mts with aac-latm, switching to FFmpeg Safe Mode for audio encoding is the better workaround. With FFmpeg Safe Mode the audio delay is ignored, and for this capture is the right thing. Somehow MediaInfo is exposing a wrong delay.
This is what I said in my first post about the problem:
Quote:
Specifying "FFmpeg Safe Mode" under preferences works, but there is no way to process audio.
This may be all which most users need, but others like me really like to be able to manipulate the audo tracks.

Quote:
Originally Posted by MrC View Post
I have found that remuxing the mts to mkv has some benefits: the filesize decreases a lot (padding within the mts?) and FFMS2 is now able to decode the 2nd aac track. In this case, major drawback, the audio delay is messed up even more. Again, FFmpeg Safe Mode with the remuxed mkv works as well.
I agree, I always do this with HEVC transport streams, but mainly for the video track. None of the available source filters does a decent job seeking within such sources. Finding the right cut points when trying to cut out parts is painful. MKV is a much better format to do this.

Great that you found out that ffms2 can decode AAC-LATM when it is in an MKV container, I did not have this situation on my screen. And the messed up audio delay actually is not too challenging. You just need to use the delay value reported by MediaInfo, only reverse the prefix. Just remove the "-" prefix from the "DelayAudio" command.

My take on the whole issue is that such captured transport streams always have non-decodable B-Frames at the beginning. And all the available source filters have different ways how they treat these non-decodable frames. Luckily we only need to deal with DirectShow based source filters and ffms2 (Donald Graft handles such sources differently again).


Cheers
manolito
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