MPC & Dolby TrueHD issue

Hello there to all:

Usually when I join a forum such as this it's because I've got a problem & I've not been able to solve it myself, such is the case now,

I've never had any issue with MPC in all the time (years) I've made use of it as my major media player, but now that TrueHD/ATMOS is present MPC can't seem to play the audio for me.

My pc is graphics HDMI connected to my flat screen TV, the hd audio card is spidf/optical connected to my processor/receiver, up to now I've had no issue where regular AC3/DTS/DTS MA is concerned, all go to the receiver as expected.

For whatever reason the default lav filters that are installed in MPC can't pass a trueHD signal out to the card.

I'm currently using MPC 1.71, and have manually installed the later .0.63 Lav standalone filter pack that is now part of version 1.77, (I still use 1.71 because I can drag & drop a custom shader pack into the program that the later version no longer allows).
The 0.63 lav filters ARE registered via the .bat command,

whenever I start an HD movie that has a TrueHD as the audio I will get a warning from MPC *could not render some of the pins in the graph, you may not have the needed codes or filters installed in the system*



I close that window and MPC will start the file but there is no audio,

I've been dealing with this problem for months, tried different MPC versions, removing the lav filters for the Haali filters with no success, this only happens when a TrueHD file is involved.

I was under the impression that the *needed* codes are part of the MPC program, where else would they be?

Any light on this IS appreciated, I'm getting tired of demuxing TrueHD files, converting to wav so I can use DTS MA suite to re-encode to DTS just to get the audio functioning.

Op/sys is Win7.

MPC-HC 1.7.7 still supports custom Shaders. Just put the files in the Shaders subfolder of the MPC-HC installation folder. Rename the files to .hlsl extension. They are still just plain text files, so your old shaders are compatible.

The error message indicates that the audio renderer did not accept 8 channel PCM (=uncompressed/decoded audio) input. That is not surprising, since SPDIF has limited bandwidth. Not enough for transferring 8 channels of uncompressed audio with a 192kHz samplerate.

Simple solution:
In LAV Audio decoder, enable the Mixer and set it to Stereo. You could also try 5.1, but that might be too much as well. Downmixing will only be done for audio formats that are decoded by LAV. Everything for which bitstreaming is enabled, will remain untouched.

Better quality, but more complex solution (if downmixing to 5.1 doesn't work either):
Re-encode the decoded audio to AC3. This can be done in real-time. For example with ffdshow audio processor, or with ReClock audio renderer.

Hi there:

Thx for the help,

where the shaders are concerned.......the input that I have is a custom shader that I came across on a forum that I saved as a webpage, that entry is not technically a file that I can name as an hlsl file,

what I have been doing is to open MPC and then open the shaders (ctrl/9) program and then copy the entire entry from the saved webpage into the shader, name it, PS 3 it, then register it, it then appears in the selected shaders I can choose from.

How would I go about copying all those entries and make a file from them?......never done this up to now....

On the lav situation, when you mentioned *better quality*........well, that's essentially what I've had to do when demuxing the audio file, converting back to wav (Eac3to), then re-encoding to DTS in DTS-MA suite.

so, does the problem actually lie in MPC where the decoder is concerned or elsewhere, my audio card has no problem when playing hi-res audio files that are encoded to 24bit 192khz fed to my receiver.

The shaders are just simple text files. So you can just copy/paste the shader code into and empty text file and save it as a .hlsl file. Just try opening one of those files with a text editor (such as Notepad.exe). You will see that it looks just like the code you used in old versions.

Re-encoding in realtime means that it is done during playback. It is just a matter of configuration. Once set, no extra steps are required before playback.

Bitstreaming other formats works fine because those are in a compressed format. Uncompressed audio consists of much more data.

Thx for the tip on the shaders, did just as you directed & I entered the custom file into MPC 1.77 (updated to that version), and the shader appears there.

I was lead to believe that one had to *create* an HLSL file with a C+++ program, that's why I hadn't gone to the later version of MPC,

On the bitstreaming question, the hi res audio albums I have (Led Zeppelin, Rush etc etc) ARE in wav format (I convert them back to wav from flac), they are quite large (near 2 gig +), no issues where transmission from pc to receiver is concerned. So I'm still lost as to why this issue where TrueHD is concerned.

But, I do not use MPC for my audio music files, Winamp takes care of that.

How many audio channels does those WAV files have? And what sample rate? I suspect both are lower than in the TrueHD case.

Which brand and model receiver do you have? Does it actually support 7.1 input?

The audio files are stereo, as stated they are 24bit, 192khz,

I can demux the TrueHD audio track, convert it to 8 wav channels with eac3to, run them all thru Soundforge & output them at 24bit, then just for the sake of trying.... re-encode them with DTS MA suite to 24 bit, 192khz 7.1 (huge file) and it will play with no issues in MPC,

my receiver is an older Technics Digital Processor/Receiver combination, it is not the issue, the signal is not getting to it, the signal is not even getting to the soundcard.

Baffled

The signal is not getting to the sound card because the audio renderer rejected it. Decoding worked fine.

Have you tried enabling the Mixer in LAV Audio decoder? It is at least interesting to know if reducing the number of channels makes any difference.

You should also check if perhaps a newer version of your sound driver is available.

Alright......let's throw another twist into this........

I have two operating systems on my hard drive.....W7 is my major op/sys & WinXP SP3 is alongside it, I use XP for all of my inhouse recording/midi work, creating/editing my music recordings,

both op/sys use the same soundcard, seeing I had not done so I installed MPC (1.77.1) into XP, set it up to the same parameters as W7,

load in a mkv movie........ low & behold I can play a TrueHD audio track movie in MPC, as the movie is playing I can bring up on the screen the program options and cursor over audio and I can see the default 8 channel Truehd file is selected over the imbedded 5 channel AC3.

Now I'm even more baffled.......what can be going wrong in 7 but isn't wrong in XP??

There's nothing I can alter where the soundcard drivers are concerned, there are no warnings of incorrect .dll's installed.

Check the settings in Windows Control Panel > Sound. There might be differences on the two Windows installs. The default audio device should be the same. Select that audio device and go to Properties. The settings there should also be the same on both systems.

With updating the driver, I mean look for a newer version of it. If you need help finding a driver, then post this info:
Codec Tweak Tool > Generate Log
That contains details about your hardware and current drivers.

Well,

I really don't know where to elsewhere look, from what I can see W7 has the correct drivers (and the latest), there are no changes I can make where audio properties are concerned, in MPC on the *options/output* page I can alter from either *directsound* digital interface (spidif) or *directsound*speakers, neither get me past this situation, just completely baffled, there has to be some sort of problem in 7 for passing the audio signal where this format is concerned from the player to the card that XP isn't encountering.

Well, you should really test that Mixer setting in LAV Audio decoder that I mentioned before.

If your hardware supports it you could also remove the optical cable and do everything through HDMI.

LOL.......nope, nothing works, mixer gets me nada, even using the HDMI out as the path for the audio ( which in my case sends the audio directly to the flat screen) still displays that error message from MPC *output can't find the pins....*

has to be something in 7's structure for the audio that just doesn't like Truehd's format, has me completely stymied.

Are you now using the latest version of MPC-HC or still the old version? Because your screenshot shows that you are using the internal copy of LAV Filters. This means that the external installed copy isn't used and you may have an old version that does not yet properly handle the Atmos stuff. Overwrite the files in the LAVFilters subfolder, or disable the internal one in MPC-HC settings.

I'm using 1.77, the lav filters (0.63) are built into this version, if one wanted to override these particular filters for another pack, should one remove them entirely?...or does one install into the program a completely different pack (and what pack would I look for?) and select this alternative from within the *external filters* tab and at the same time un-check the source filters (left window) & transform (right window) filters in the internal filters tab?

1.7.8 has been released today. It includes the latest version of LAV Filters as well.

In general, it is sufficient to disable internal filters when wanting to use an external one. Source filters = splitter, transform = decoders. The external filter settings are for overriding the standard merits of filters, which is something you usually don't need to do.

Installed the new release that has the updated Lav filters...guess what.....no joy...

Then I am out of ideas.

LOL.......so am I,

I am wondering if this is a DirectX anomaly, XP runs on DX9, whereas 7 runs on DX11, I can't think of anything else that substantially differs from the two op/sys.

It is unrelated to DirectX. And Win7 actually also supports older versions of DirectX. Windows 7 does have a much different handling of audio than XP, actually better and less dependent on driver quirks. But your problem is not likely a fault of Windows 7. Otherwise more people would suffer from it.