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Old 19th July 2018, 21:08   #3118  |  Link
MrC
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Join Date: Apr 2006
Location: Italy
Posts: 1,302
Quote:
Originally Posted by manolito View Post
I have a request for changing the handling of FFmpegSource...

It seems that many versions of ffms2 have a problem when fpsnum/fpsden are used to guarantee CFR output. A recent discussion was started here:
https://forum.doom9.org/showthread.p...39#post1845939

AVStoDVD is only rarely affected, but generally the safest workaround is to abandon the fpsnum/fpsden parameters completely and instead use ChangeFPS following the ffvideosource call. (I know that it was me pushing the use of fpsnum/fpsden, but this was before the issues became apparent).

For AVStoDVD this will require two changes:
1. The A2DSource.avsi must be changed. An updated file is here:
https://www.sendspace.com/file/7b2tux

2. If FFmpegSource is specified under "Preferences" then the A2D executable must be changed like this:
This script line

must become this


Cheers
manolito
I have had a quick look to the mentioned thread, and, frankly speaking , I would not alter the current A2D code to deal with similar AVI titles. Also, the approximation to use 2997/100 config should be safer than the more accurate 30000/1001

Quote:
Originally Posted by manolito View Post
I found an issue with all versions of ffms2 with AAC-LATM audio streams. Unfortunately this evil audio format is one of the standards for German DVB-T2 broadcasts.

I posted the detailed problem plus a sample file here:
https://forum.doom9.org/showthread.p...72#post1846272

According to qyot27 a (sort of) working solution would be to index the source manually before calling ffaudiosource. But still the second audio track cannot be accessed.

LAVFilters have no problems with this audio format. But unfortunately AVStoDVD can only access the first audio track with DirectShowSource. For the second audio track ffmpegsource must be used.

I think that only very few users will be affected by this issue, it is probably not worth spending any time to fix it.


Cheers
manolito


//EDIT//
Turned out that it was surprisingly difficult to find a workaround for such sources to make them work in AVStoDVD. It is easy if you only need the first audio track, but if the second track is also needed (and you want audio to be in sync) then only methods which do not use AviSynth for audio seem to work.

Specifying "FFmpeg Safe Mode" under preferences works, but there is no way to process audio. The other option is to use FFmpeg to preprocess the source. I use dmMediaConverter as the front end for FFmpeg. Repacking the source to MKV, using copy mode for video and converting both audio tracks to AC3 did the trick. The front end makes it easy to use built-in FFmpeg audio filters, and the AC3 encoder is first rate. Then feed the resulting MKV to AVStoDVD and use Direct Stream Copy for the audio tracks. This is my preferred method.
That's weird because it could become a general issue if the AAC-LATM standard will become popular. Do you know if qyot27 has plans to finally fix that?

An actual workaround for A2D could be to demux the 2nd (and above) track when a containing title is added. Not very elegant indeed. By the way I can add an entry to the FAQ/Audio section.



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