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27th December 2015, 13:56 | #13761 | Link |
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Dolby TrueHD Atmos issue
I might have found another bug - this time in the decoder used for Dolby TrueHD tracks in conjunction with Dolby Atmos encodings (eac3to 3.31).
In the case of Léon (US Supreme Cinema Series), the decoding of the Atmos track leads to weird cracklings at certain positions whereas the decoding of the embedded AC3 track is flawless. |
27th December 2015, 15:49 | #13762 | Link |
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Have you tested decoding with a recent ffmpeg build? If it also causes the issue, you need to report the bug to the ffmpeg devs.
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28th December 2015, 10:39 | #13764 | Link |
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There is no guarantee your TrueHD stream isn't just broken.
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28th December 2015, 21:28 | #13765 | Link |
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@nevcairiel
Which is why I wanted to take some precaution and used the word "might" wisely. Guilty as charged that the source is not really an official one but to double-check this, I used a remuxed one and a nominal 1:1 copy which has to be put together by eac3to. Just for my defense - NO, I won't buy that movie for the fourth time (two DVDs and the LaserDisc is enough now), just because they finally get a half-way decent video master they could have come up with in the first place (so annoying). Besides that, I don't consider this Atmos remix to be that great due to its "tinny" acoustics and of course, the 4K remastered Blu-ray doesn't contain the 5.1 mix. FFmpeg states something about "lossless" check failed, but only with one of the two sources as far as I remember - the crackled PCM result is similar though. Maybe someone can grab the original and double- (or rather: triple-) check. |
30th December 2015, 02:48 | #13766 | Link |
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Another oddity:
When decoding this DTS-HD MA track, there is some kind of contradiction in the log output of eac3to: on one hand, libDcaDec is allegedly outputting 16 bit data, however the resulting PCM file uses all the 24 bits according to eac3to at the same time. In any case, the output at least matches the ArcSoft decoder's. Yet again, I don't know if it's really lossless or not. |
30th December 2015, 12:33 | #13767 | Link |
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Have anbody here succes with the Sonic Audio Decoder on W7/8.1 x64 ?
I tried v4.2 and 4.3 from the Decoder Pack, also v5 from, Sonic Cinevision. The Sonic Cinemaster® Audio Decoder 4.3 appears in Directshow registered Filters and i can use it MPC HC etc But eac3to gives me : The Sonic Audio Decoder (3.31.0.0) doesn't seem to be installed I placed the Files in Systems Folder etc etc, nothing helps. Its a clean System without any Decoder Packages etc. Is there trick on W8 x64 ? Thanks |
6th January 2016, 07:05 | #13769 | Link |
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-r8brain
Anybody notice that the actual usage output of the current version doesn't show the:
-r8brain use r8brain resampler instead of SSRC option, unlike the output shown in the post at the top of this thread? Version number match |
6th January 2016, 13:23 | #13771 | Link |
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@madshi
Instead of using r8brain, would not it be better use ffmpeg (soxr)? http://src.infinitewave.ca/
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6th January 2016, 16:26 | #13772 | Link | |
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Quote:
That's a lossy to lossy conversion. Why would you want to do that? IMHO dts is a better sounding format anyway. |
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6th January 2016, 16:52 | #13773 | Link | |
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Quote:
Thanks for the post. I'm using eac3to to convert aac to ac3, and struggling to understanding the delay issue. Appreciate if you could assist. 1. If direct from aac to ac3, 5ms silence seems to be inserted. This appears to agree with ffmpeg. Audacity is used for comparing the two. 2. If going from ts/mkv to ac3, Nero Audio Decoder would be used. This would seem to remove 42ms if the audio begins with silence. So the resulting ac3 would be either -37ms shorter or +5ms longer, depending on the initial content. Does this behavior look correct to you? Is there a way not to use Nero for step 2? Many thanks and best regards. |
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6th January 2016, 17:32 | #13774 | Link | ||||
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Quote:
Is correct using eac3to (dcadec) and Aften encoder. But, talking about free soft, now is better ffmpeg: ffmpeg -acodec libdcadec -i source.dts -acodec ac3 -center_mixlev 0.707 -surround_mixlev 0.707 -ab 640k destination.ac3 Quote:
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Talking about size/quality AC3 is better and AAC much better. Talking about compatibility AC3 is better.
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6th January 2016, 18:01 | #13775 | Link |
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The "core" dts audio format on DVD Video may be a low-loss format when using the bitrate close to LPCM 16-bit stereo (1536 kbps); but it is not lossless. And the bitrate close to LPCM 16-bit mono (768 kbps) is even audibly lossy. It may use less psycho-acoustic filtering than AC3. But that doesn't make it "better": dts tries to retain even probably inaudible frequencies only "audiophiles" believe to recognize (but couldn't prove), so it possibly lacks in accuracy for audible frequencies instead.
Its purpose was to compress multi-channel audio to bitrates close to comparable usual bitrates of 16-bit LPCM in mono or stereo, and it is still a format based on 16-bit integer samples. Dolby Digital (AC3) instead works with floating point parameters, therefore it may have a better dynamic range if it compresses original 24-bit integer or even floating point samples (important especially for almost slient scenes, like in classical music), keeping the audio audible despite a loss of frequency parts excluded by psycho-acoustic filters, because you will probably not recognize them anyway (except on a rather psychological level). |
6th January 2016, 18:19 | #13776 | Link | |||
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Quote:
BTW, with Aften, you can avoid the insertion of 5 ms of silence with, for instance: eac3to INPUT stdout.wav | Aften -b 192 -pad 0 -readtoeof 1 - OUTPUT.ac3 Quote:
"The directshow Nero 7 decoder, used by eac3to to decode .aac, cut the first 1024 samples (21,333 ms in 48 KHz) in 2.0" Then, always cut 21 ms, and (without -pad 0) finish with 16 ms shorter. The Nero Audio Decoder (NeroAacDec.exe) is not used by eac3to at all. Quote:
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6th January 2016, 21:09 | #13777 | Link | |||||
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Quote:
And also for a compatibility a little bit Quote:
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Last question, what about remapping channel ? Is there a risk to have an issue with wrong channel remapping if I convert DTS to AC3 ? Thank you ! |
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6th January 2016, 21:30 | #13778 | Link | |
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Quote:
In the case of AC3, you can use ffmpeg to generate level scaling metadata, but the results are not ideal since obvious pumping artifacts can be introduced during playback. Last edited by AlexKane; 6th January 2016 at 21:41. |
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6th January 2016, 23:00 | #13779 | Link | ||
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Quote:
"eac3to.exe source.dts destination.ac3" (640 Kb/s is the default also) Quote:
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6th January 2016, 23:27 | #13780 | Link | |
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Quote:
Ok thanks but I don't understand why do you say "talking about free soft" for ffmpeg, dcadec and Aften are commercial softwares ? |
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