DGDemux development

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Rocky
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Re: DGDemux development

Post by Rocky » Tue Mar 31, 2020 1:33 pm

So it will open some sample files I downloaded but fails on anything from a UHD bluray. Any ideas?

gonca
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Re: DGDemux development

Post by gonca » Tue Mar 31, 2020 2:36 pm

Did you try to Import as Raw Data?
Worked on my system

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Rocky
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Re: DGDemux development

Post by Rocky » Tue Mar 31, 2020 3:46 pm

It may appear to work. But raw data is uncompressed and raw with no metadata. A THD file is not that. You can read anything as raw!

gonca
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Re: DGDemux development

Post by gonca » Tue Mar 31, 2020 7:47 pm

Well I found this
https://forum.audacityteam.org/viewtopic.php?t=88387
Seems there is a size issue, apparently it will only open smaller thd (size) files
Also ffmpeg plugin 2.2.2 does not support "thd atmos"

gonca
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Re: DGDemux development

Post by gonca » Tue Mar 31, 2020 8:02 pm

Quick test
BluRay thd track with no atmos 2.38 GB opens fine
UHD thd track with atmos 4.00 GB does not open
UHD thd track with atmos 3.49 GB does not open
Issue does appear to be atmos

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MeteorRain
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Re: DGDemux development

Post by MeteorRain » Wed Apr 01, 2020 5:24 am

Kindly remind that you mis-wrote someone as me in the binary update ;)

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Rocky
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Re: DGDemux development

Post by Rocky » Wed Apr 01, 2020 6:42 am

MeteorRain wrote:
Wed Apr 01, 2020 5:24 am
Kindly remind that you mis-wrote someone as me in the binary update ;)
Fixed. Thank you for alerting me.

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Rocky
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Re: DGDemux development

Post by Rocky » Wed Apr 01, 2020 7:23 am

Yes, my research confirms it is caused by the atmos. I wonder if what domy did was convert to flac using a recent ffmpeg and then rename it as file.thd_. You see that _ in his audacity screenshot. I will try it this way.

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Rocky
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Re: DGDemux development

Post by Rocky » Wed Apr 01, 2020 7:47 am

Or maybe he used ffmpeg to just strip the atmos. I know that can be done but don't have a command line for it. Anybody?

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Rocky
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Re: DGDemux development

Post by Rocky » Wed Apr 01, 2020 9:20 am

OK, I found a working command line:

ffmpeg -i file.thd -c:a copy -bsf:a truehd_core out.thd

Now out.thd can be opened by audacity (with ffmpeg installed). Here are the timings I get for Monsters:

video: 6258.425 seconds
embedded ac3 (corrected by gaps processing): 6258.432 (good sync to video, 7ms async by end of stream)
truehd: 6258.528 (bad async of 103ms by end of stream)

The truehd is out of sync and so it is clear that I need to implement gaps processing for THD. It may also be interesting to add an option to DGDemux to strip the ATMOS on demuxing.

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