Can ReClock be used with bitstreamed DTS-MA/TrueHD etc over a Xonar card?

[myurkus]

From my understanding, I think the answer is "no" it is not possible. The Xonar card only correctly bit-streams DTS-MA/TrueHD (without down-sampling) using ArcSoft's TMT.

After some work, I found I was able to use MPC-HC/ffdshow etc to still bit-stream these formats when using the Arcsoft Renderer as the output (instead of Reclock.)

Since the audio has to be directly bit-streamed in such a specific and untouched way (like the audio equivalent of DXVA rules,) I figured that ReClock is impossible. However, I really miss ReClock in these instances (Madvr reports a frame-drop every minute instead of every day or so using ReClock...) And I have found some threads that seem to indicate there is a possibility...but I am skeptical that when "mucking" with the audio, such as decoding it to PCM, that the lossless quality is lost.

So is there any way to make this work? I have head everything from using DirectSound instead of WASAPI to others saying that only WASAPI will work.

At the very least, is my understanding that ReClock must decode or read a decoded audio track in order to read the audio data? (I.e. when selecting "accept bitstream formats" it is actually decoding and re-encoding the audio?)

Thanks much for your help!
MikeY

[CraziFuzzy]

I am perfectly happy sending multichanel PCM to my receiver. The HD Audio codecs are indeed lossless, meaning every bit coming out is the same it went into the encoder. There is no 'mucking' with the audio in this case. What it DOES do is allows ReClock to do it's mucking to make things correct, and smooth.

[myurkus]

Originally Posted by CraziFuzzy

I am perfectly happy sending multichanel PCM to my receiver. The HD Audio codecs are indeed lossless, meaning every bit coming out is the same it went into the encoder. There is no 'mucking' with the audio in this case. What it DOES do is allows ReClock to do it's mucking to make things correct, and smooth.

Thanks for your response!

I absolutely agree with this, and this is what I do for 90% of my mkv's. However, there is a big caveat when trying to use lossless audio on a Xonar card: it is setup so that it can only be passed-through using Arcsoft TMT. Otherwise, like all cards before this (and before the newest generation Video-cards etc) it will down-sample to, for instance, DTS core when doing the decoding. A couple years ago this was a big mess and before Xonar it was literally impossible to send uncompressed audio in any digital format (even as PCM!) I found a workaround to play mkv's with TrueHD or DTS-MA by using the "Arcsoft Renderer" filter, but that is a renderer not a decoder. (I.e. it is used instead of ReClock, not in conjunction with...)

EDIT: After writing all of this I found that this might NOT just be a Xonar issue. See the final postscript of this message, it seems that for DTS-MA at least there is no such thing as a software decoder that correctly decodes it. (It will still sound fine and all, but essentially all software decoders just read the DTS core file and ignore the "MA/MasterAudio" part of the track, which is obviously the part of the track that makes it truly lossless...)

Essentially it was (and is) a big mess with the movie industry worried about piracy using HTPC's in conjunction with an ignorant public that mostly did not even realize it was down-sampling! (E.g. companies like Cyberlink[PowerDVD] touted the support for DTS-MA/TrueHD/uncompressed PCM. However, in reality, they only played a down-sampled version of the track.

To put it another way, if I have a DTS-MA file, if I decode it to PCM in ffdShow or LAV (which is what I do with all of my other files) when looking at the filter input pin on ReClock, I would only see the 1536 Kbps bit-rate of the DTS-core. I.e. it loses all of the uncompressed info while doing the decoding. Thus, I need to pass-through the DTS-MA track completely untouched, which unfortunately includes losing the ability to ReClock...

CraziFuzzy - assuming you have a new-gen video-card or something, then you are absolutely correct that you should be able to happily decode a lossless track to PCM and not worry about it...unfortunately, AFAIK, this is not the case with my setup. (Edit: see "PPSS" below...this may be an issue with any hardware! )

I wanted to post this on a Xonar forum, as much of this is an issue with them; however, there are none as active (with truly knowledgeable people) as this forum (possibly aside from a long singular avsForum thread...)

Thanks again!
MikeY

PS - If interested, the first post of the following link and the pdf file in the post referenced by this link shows what I have to go through: DTS-HD and TrueHD with Xonar HDAV1.3 (Note: I do not use MediaPortal, but the idea is the same since it is a chain of external codecs...)

PPSS - Actually, I do not think there are any working external decoders that can correctly decode DTS-MA regardless of the setup. FFMPEG (used by ffdShow) can only decode core DTS. Both it and LAV can do TrueHD, but neither will do DTS-MA outside the core audio. One of several discussions on this issue...I have not tried the FLAC suggestion though.