TrueHD/DTS-HD/LPCM

[CiNcH]

Hey guys,

I have read so many things now but i still have problems in understanding how the lossless audio formats are copy-protected and which decoder is fully capable of decoding them (in case of TrueHD and DTS-HD not just the lossy core).

So my precise questions are:

Are the lossless parts of a BDMV TrueHD/DTS-HD stream separately crypted? (or the same question put another way... are they still crypted after they have been copied to HDD with AnyDVD HD?)

If the "HD-part" within TrueHD/DTS-HD is crypted separately, is this also true for LPCM?

Is there a decoder existing that if I feed it a BDMV TrueHD and/or DTS-HD stream can fully decode it and output PCM with all channels and not downsampled?

[BDMinus]

Anydvd HD removes AACS and BD+ protections making the files basically DRM-free. Theres a command line utility called Eac3to that can demux/decode/recode all the audio formats on hd dvd/bluy-ray. Check out this thread for all the information: http://forum.doom9.org/showthread.php?t=125966

[CiNcH]

OK, thanks, that answers my question about the DRM-stuff.

What I need now is decoders based on DirectShow, processing the HD-parts without downmixing/downconverting/downsampling, as we do the demuxing ourselves and just want to perform playback without reencoding. I know eac3to but I do not know how it decodes the stuff!? Maybe you can help me. Otherwise I will most likely have to read through 101 pages.

[CiNcH]

evaluation of available decoders:

The Sonic (E-)AC3 decoder forcefully applies DRC. As a result I do not recommend to use the Sonic (E-)AC3 decoder. The current version of the Sonic TrueHD decoder doesn't work properly at all. The Sonic DTS decoder is very good for DTS, DTS-ES, DTS-96/24, DTS-HD Master Audio and DTS-HD High Resolution tracks. The only problem is that it decodes DTS-HD 7.1 tracks only as 5.1. Most DTS-ES and DTS-HD Master Audio 6.1 tracks are fully decoded as 6.1, though. The Nero (E-)AC3 and Nero TrueHD decoders are working perfectly fine, but are limited to 5.1 channels. The Nero DTS decoder ignores the additional DTS-HD information and only decodes the DTS core. The Cyberlink decoders always only output 16bit and can't be used outside of PowerDVD. So they currently do not make a lot of sense for eac3to. The libav/ffmpeg (E-)AC3 and DTS decoders work really well, but the output is not 100% identical to the Dolby/DTS reference decoders. I'm not sure whether there's a difference in audio quality. Decide for yourself. The libav/ffmpeg (E-)AC3 and DTS decoders are both limited to 5.1. Furthermore the DTS decoder ignores the additional DTS-HD information. The libav/ffmpeg TrueHD decoder works perfectly fine including full 7.1 decoding. The ArcSoft DTS decoder seems to be perfect for DTS and DTS-HD decoding. It supports every format and channel configuration that exists including 6.1 and 7.1. The ArcSoft TrueHD and ArcSoft (E-)AC3 decoders are currently not supported by eac3to.

Does not look too good concerning decoders..

[Adbear]

Sieht ja noch nicht so rosig aus mit den Dekodern.

English only in this forum

[CiNcH]

I know of course, force of habit... edited my post...

[Turtleggjp]

Does not look too good concerning decoders..

Actually, it is pretty good. EAC3to supports all formats of TrueHD natively with its libav code, and all you need for full DTS support is Arcsoft Total Media Theater. Ok, I know many people have had trouble with TMT, but at least you can try it out first to see if it works on your system. The only format you need to watch out for is Dolby Digital Plus (EAC3). I don't think you can try Nero (or at least the HD plugin that you need) first, so you'll have to take a chance there.

[CiNcH]

With our player we can at least play every audio format, but we are currently extracting the cores on-the-fly at the moment for TrueHD/EAC3/DTS-HD on BD.

I will give the Arcsoft audio decoder a shot on DTS-HD.

eac3to is no option as it is not a DirectShow decoder. Maybe writing a DirectShow wrapper for ffmpeg/libav is an option but I think that the ffdshow guys will take it over..

Actually I am not a fan of all those huge packages like the Nero decoders coming with BurningRom and all. They install a hell of a lot filters which can't be too good if you build up your DirectShow system with merits. The whole thing is in a mess pretty fast. Also TMT is quite a package...

[BDMinus]

From whats ive been able to gather ALL of the available directshow decoders downsample to 16bit/48khz because there's no protected audio path. some dumb bluray licensing or aacs requirement. the prefered decoders that eac3to uses (arcsoft for dts, nero 7 for eac3, etc) are the ones that the programmer of eac3to has somehow managed to get those decoders to output reference or nearly reference decoded audio. If you want untouched audio the closest you can get is using the program to demux the audio and video into separate files, converting the audio to FLAC, remuxing those into something like MKV and playing it back in media player classic home cinema or something similar. there's a complete guide on how to do that somewhere on the board.

OK, thanks, that answers my question about the DRM-stuff.

What I need now is decoders based on DirectShow, processing the HD-parts without downmixing/downconverting/downsampling, as we do the demuxing ourselves and just want to perform playback without reencoding. I know eac3to but I do not know how it decodes the stuff!? Maybe you can help me. Otherwise I will most likely have to read through 101 pages.

[CiNcH]

From whats ive been able to gather ALL of the available directshow decoders downsample to 16bit/48khz because there's no protected audio path. some dumb bluray licensing or aacs requirement.

Why would they do it if AACS was not present any longer? Just like as there is no HDCP any longer there should not be any PaP present either...

[BDMinus]

I'm still scratching my head over that one myself. I'm guessing that the cyberlink, arcsoft etc figure that the only blu-rays with high-definition audio will be commercially produced ones whether it has AACS or not so they downsample regardless. HDCP also doesn't apply to analog displays I think. I ran a BD advisor tool and it gave me a green light for my display even though its through VGA.

Why would they do it if AACS was not present any longer? Just like as there is no HDCP any longer there should not be any PaP present either...

[ile]

So is there any directshow decoder for true hd sound?

[leeperry]

I like AC3Filter coz it doesn't do any DRC and can output 32float(useful on lossy files), but it doesn't decode DTS 96/24 :(

Sonic 4.3 is very nice but I can't get it to decode DTS at all in DS players...only in eac3to :confused:

anyway 4.2 works fine, but it does some ugly DRC....so what's your best option for DTS 96/24 then? Intervideo's decoder?