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Old 20th October 2015, 13:42   #13561  |  Link
LigH
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A good dither algorithm is not necessarily random, it may even be better. If the original values with higher precision are known, then they can be used to calculate lower precision values with a medium "virtual precision" by distributing the error across neighbor values, so that the weighted average of neighbor samples approaches the former more precise value better. From image processing you may know ordered dither patterns (Bayer) or error propagation noise (Floyd-Steinberg etc.); audio dithering can work in a similar way. Properly implemented (in relation to "noise shaping"), it can do miracles in low volume scenes. I do not know, though, how eac3to works in this regard...
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Old 20th October 2015, 15:55   #13562  |  Link
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Quote:
Originally Posted by ndjamena View Post
And when down sampling to 16 bit eac3to DOESN'T try to squeeze the number from a scale of 16777215 to a scale of 65535, it just removes the lower eight bits, then applies "dithering" which is basically just random noise to hide the artificial "colouring" of the sound any down sampling method must create It applies the dithering even if what it's processing is nothing but perfect silence. The -dontdither switch supresses the application of any dithering.
That is the correct way to do this. Anything else would not result in the expected audio. And you should never disable dithering.

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A good dither algorithm is not necessarily random, it may even be better.
Audio Dithering is generally always based on randomness, so you can guarantee no unwanted harmonic interference piles up somewhere.
Even "Noise Shaping" uses randomness at its base, its just transformed slightly to move the random noise into desired frequency regions.
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Last edited by nevcairiel; 20th October 2015 at 15:57.
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Old 28th October 2015, 09:11   #13563  |  Link
Motenai Yoda
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Quote:
Originally Posted by ndjamena View Post
And when down sampling to 16 bit eac3to DOESN'T try to squeeze the number from a scale of 16777215 to a scale of 65535, it just removes the lower eight bits
It's the same thing, divide by 256 then truncate (if you don't work in int), give you bit identical result than just a 8bit shift to right.
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Old 30th October 2015, 15:28   #13564  |  Link
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is the dcadec decoder able to decode DTS:X streams?
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Old 30th October 2015, 16:12   #13565  |  Link
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2015 DTS Blu-Ray Demo Disc Vol.19

Decode Divergent DTS:X without errors.

MKV, 1 video track, 1 audio track, 0:02:01, 24p /1.001
1: h264/AVC, English, 1080p24 /1.001 (16:9)
2: DTS Master Audio, English, 7.1 channels, 24 bits, 48kHz
(core: DTS, 5.1 channels, 1509kbps, 48kHz)
[a02] dts, 48000, 7.1
[a02] Extracting audio track number 2...
[a02] Decoding with libDcaDec DTS Decoder...
[a02] Writing WAV...
[a02] Creating file "V:\DTSX Demo - Divergent.wav"...
[a02] The original audio track has a constant bit depth of 24 bits.
Video track 1 contains 2904 frames.
eac3to processing took 14 seconds.
Done.
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Old 30th October 2015, 18:09   #13566  |  Link
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but can we be sure that everything in it has been decoded and used correctly? how does DTS:X work, is it some extension like atmos for TrueHD? maybe then just the "core" DTS-HD MA track was used and not the DTS:X extension?
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Old 30th October 2015, 18:37   #13567  |  Link
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sound is fine.
the core is 5.1 not 7.1
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Old 30th October 2015, 18:41   #13568  |  Link
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Quote:
Originally Posted by Smithy View Post
sound is fine.
the core is 5.1 not 7.1
I dont mean the DTS core inside the DTS-HD MA track, but something like possibly a DTS-HD MA core inside the DTS:X track. or a DTS:X extension which could be stripped or dropped and perhaps we wouldnt know of it.
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Old 30th October 2015, 18:44   #13569  |  Link
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Quote:
Originally Posted by Smithy View Post
sound is fine.
the core is 5.1 not 7.1
I mean not the DTS core inside the DTS-HD MA track, but something like possibly DTS-HD MA core inside the DTS:X track. or DTS:X extension which could be stripped or dropped and perhaps we wouldnt know. so eac3to could either recognize only this known "DTS-HD MA" core inside the full DTS:X track or not recognize the DTS:X extension of the full track (in case it works like an extension) and therefore disregards the part it doesnt know.

dcadec was last modified 5 months ago on github, not sure how many DTS:X test samples have already been available back then to help with the implementation.
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Old 30th October 2015, 18:50   #13570  |  Link
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yes, this part is doesn't know

but dts-hd ma is the core Track of DTS:X for backward Compatibility like THD (Atmos) or PCM (Auro3D)

and DTS:X is more Special vs. THD ATMOS, maybe its possible to decode DTS:X
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Old 1st November 2015, 15:44   #13571  |  Link
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Quote:
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^ I guess he caught a wrong URL in his clipboard; Ctrl+C is sometimes unreliable. It's probably this post (plus some previous and following). Apparently Transport Streams are not as trivial and unambiguous as one may expect.
All that link does is take me back to the top of that page.
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Old 1st November 2015, 16:21   #13572  |  Link
madshi
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eac3to v3.30 released

http://madshi.net/eac3to.zip

Code:
* libDcaDec is now default for all DTS tracks except XSA / low bitrate
* fixed: #310: Use ffmpeg like external encoder
* fixed: #312: Convert to wav with a big negative delay works incorrectly
* fixed: #314: 'edit' option adds one frame less than expected
* fixed: #345: Fails to decode Atmos track with no embedded AC3 track

Last edited by madshi; 1st November 2015 at 16:57.
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Old 1st November 2015, 16:30   #13573  |  Link
SeeMoreDigital
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Thanks madshi
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Old 1st November 2015, 20:10   #13574  |  Link
ron spencer
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fixed #345 is sweet!!

for:

Quote:
libDcaDec is now default for all DTS tracks except XSA / low bitrate

Does this mean the Arcsoft decoder is not longer needed?
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Old 1st November 2015, 22:34   #13575  |  Link
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Thanks madshi!

Quote:
Originally Posted by ron spencer View Post
Does this mean the Arcsoft decoder is not longer needed?
Only for DTS-Express:

Quote:
* libDcaDec is now default for all DTS tracks except XSA / low bitrate
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Old 2nd November 2015, 05:45   #13576  |  Link
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Good news, everybody!

Thanks for the update.
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Old 2nd November 2015, 10:03   #13577  |  Link
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Thanks for the update, but I'm just too late to report that libDcaDec may have a bug. It fails to decode some DTS HD MA tracks extracted from BDs, with the message "Synchronisation error". However, as far as I can tell, there is no sync error, the track seems perfect, I can't hear any glitch, the DTS core can be extracted without problem and the other decoders (Libav and Arcsoft) work fine. I have had that problem already 3 times, so it seems that it's not a minor problem. I have a DTSHDMA track causing the problem but unfortunately it is way too big (2.7 GB) to be uploaded somewhere, and the sync error happen near the end. Can I simply cut it at any position and upload the end of the file? I guess that will not work. Right?

Also, madshi, please reopen this bug: Failure to demux subtitle tracks from SSIF or MPLS of a 3D-BD
I have never received the notifications for the message with your request for a sample. I can't provide a sample if I don't know that it is needed.
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Old 2nd November 2015, 10:16   #13578  |  Link
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You might want to report the libdcadec problem here: https://github.com/foo86/dcadec/issues . I see no reason why the sync error wouldn't occur after cutting the file.
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Old 2nd November 2015, 10:30   #13579  |  Link
madshi
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Quote:
Originally Posted by r0lZ View Post
Thanks for the update, but I'm just too late to report that libDcaDec may have a bug. It fails to decode some DTS HD MA tracks extracted from BDs, with the message "Synchronisation error". However, as far as I can tell, there is no sync error, the track seems perfect, I can't hear any glitch, the DTS core can be extracted without problem and the other decoders (Libav and Arcsoft) work fine. I have had that problem already 3 times, so it seems that it's not a minor problem. I have a DTSHDMA track causing the problem but unfortunately it is way too big (2.7 GB) to be uploaded somewhere, and the sync error happen near the end. Can I simply cut it at any position and upload the end of the file? I guess that will not work. Right?
You can use a negative delay value in eac3to to remove the start of the track. Samples are important for problems like this. But I can't personally fix them, so you need to report such bugs to the dcaDec developer:

https://github.com/foo86/dcadec

Quote:
Originally Posted by r0lZ View Post
Also, madshi, please reopen this bug: Failure to demux subtitle tracks from SSIF or MPLS of a 3D-BD
I have never received the notifications for the message with your request for a sample. I can't provide a sample if I don't know that it is needed.
You can reopen the bug yourself, you don't need me to do that. I've already given all users the right to reopen bugs.
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Old 2nd November 2015, 15:25   #13580  |  Link
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OK, thanks.

I have already reported the problem on the dcadec bug tracker here, with this sample, and they have replied this:
Quote:
FWIW, the libdcadec wrapper in FFmpeg does not encounter any error - which indicates that the dcadec decoder is working fine, and the problem may be in reading/parsing the file.
So, it seems that the error is not related to the dcadec decoder, and may be caused by eac3to or something else. Any thoughts?

I will re-open the demux SSIF bug, but I have to create a sample first...
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