Dolby Headphone Codec - forfree-kit20’s diary

Hi Ivan,

The headphone jack in most smartphones and tablets use a CTIA TRRS signal scheme. There are 4 conductors exposed

Tip - Left audio

Ring 1 - Right audio

Ring 2 - reference ground

Sleeve - Microphone

The DAC on the audio codec has limited bandwidth as it s designed to produce baseband analogue signals that are within the audible frequency range usually 10hz - 24,000hz. Ergo, few if any phones/tablets will be capable of generating multiple discrete audio channels on the same wire using RF modulation as they simply don t have the bandwidth needed to do so. This is why Dolby Pro Logic and Dolby Pro Logic II are used. They allow four or six channels to be approximately encoded into two channels.

You as a producer can record your audio in four or six channels and then pass it through a Dolby Pro Logic or Dolby Pro Logic II encoder to derive two channels. If these two channels are not decoded, they will sound similar to the original two front channels. If they are decoded, the approximated surround channels will be recovered. The phone/tablet do not need to feature any Dolby technology for this to work, but the user does need to have a Dolby Pro Logic or Dolby Pro Logic II decoder between the DAC and the speakers. Many gaming headphones support this.

Please keep in mind though that Dolby Pro Logic encoding is not perfect and the channels will not be discrete although this may not be noticeable. The surround channels in Dolby Pro Logic are band-limited to the range of 100hz to 7Khz, which will not properly capture musical effects or low frequency effects. Dolby Pro Logic II is much better as the surround channels can span 20hz-20,000hz before attenuation occurs. By comparison, Dolby TrueHD up to 8 discrete channels with lossless encoding which is used in many BluRay movies has an almost perfectly flat frequency response from 3hz below audible range to well over 30,000 hz above audible range for each channel which means that it reproduces exactly what was captured.

I would not recommend trying to use Dolby Pro Logic for music, but Dolby Pro Logic II may work.

Any audio decoder that does what Cyberlink PowerDVD

The Investor Relations website contains information about Dolby Laboratories, Inc. business for stockholders, potential investors, and financial analysts.

There is no such thing as Dolby Digital Pro Logic, it s Dolby Pro Logic. The reason for this is that Pro Logic is analog, not digital in nature.

Dolby Digital is the name for audio compression technologies developed by Dolby Laboratories. It was originally named Dolby Stereo Digital until 1994.

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ChorniyVolk

Alright so here s my problem:

I m using a pair of HD555s might upgrade soon though and I occasionally watch movies with 5.1 channel audio. Sometimes said audio is encoded with DTS, more often AC3, and much less often, AAC.

I use The Kmplayer to view all of my video, and it does a good enough job, easily customizable and such.

Now my problem is that I used to use cyberlink s audio decoder directly for all of the multichannel audio, because with it s built in Dolby Headphone function I was able to get surround sound on my HD555s just fine. Everything was great, but I upgraded PC s and I went from Windows XP 32bit to Windows 7 64bit. I tried setting up cyberlink s audio decoder again, but now, between DTS AC3 and AAC, it ll only properly work with DTS.

For AC3 and AAC, I have to have The Kmplayer take the signal and ouput it in LPCM which I ve set to be directly decoded by cyberlink s audio decoder. This worked well enough yesterday, but today for some reason, everything has fallen apart.

I tried setting everything up like I did before, but now it won t work properly, and the video I use to test it 5.1 channel, dude s voices is heard from each one separately, then you can hear his voice moving from one speaker to another works perfectly in PowerDVD but not when I have it decoding through The Kmplayer, it won t work plainly if I set it up directly as I said, and even now with LPCM output it has stopped properly working.

Now, normally I d scour the internet for fixes, but frankly, I m tired of this shit. PowerDVD has a lot of problems for me outside of this, when I start it up it freezes my computer for 10 seconds, and then there s this problem that I ve always had with the menu when accessing it from The Kmplayer it s normal from the program itself that I don t even know what the hell I m supposed to do about:

So rather than bother with this crap any longer, I was wondering if perhaps there is another audio decoder that will work perfectly with most if not all codecs that provide more than 2 audio channels most important of those being the 3 I mentioned and be able to output surround sound for a pair of HD555s that isn t from Cyberlink. Free, not free, don t really care.

Last Edit: 19 February, 2010, :05 PM by ChorniyVolk

andy o

If you don t mind paying, then a card like an Asus DX or D1, or if you can find it, a U1 will sidestep your problem and even give you a much better solution Dolby Headphone for ALL audio, so you could use just one decoder. There are probably other cards with DH out there, but they ve been scarce since Asus bought exclusive rights to that C-Media chipset. The other cards if you can find them are more expensive.

I already have an Auzentech Prelude though

I mean, if it comes down to buying new hardware, I d be more aimed at getting headphones that support multichannel surround sound right out of the box instead of having to emulate it with the HD555s plus, I d aim for higher end stuff, so I can finally use the optical out on my soundcard .

I just figured that before I resort to buying new hardware, I d check out software.

The X-Meridian would have done it. I think it s a pity Auzen went with Creative. About headphones, I don t think there are any maybe some Pioneer infrared wireless, but those are expensive and the wireless tech is not the best. Plantronics or one of those brands sell Dolby Headphone gaming headsets but their implementation is idiotic, they take stereo, apply DPLII and then do DH. They don t do discrete 5.1 into Dolby Headphone which is what makes DH so great.

Anyway, I haven t tried the CL driver like that in Windows 7. Is it a problem of XMplayer only, or is it like that with all directshow programs.

CL driver. It s just an audio decoder isn t it.

As far as other programs, don t use many others. Like I said, I tested the test video in PowerDVD itself, and the audio decoder worked perfectly, but for whatever reason it won t work properly when used in a different media player. I might try it in MPC to make sure it s not Kmplayer but just the fact that the decoder is being used in a different program, but there s no way I m switching from The Kmplayer, best media player I ve ever used not to mention fairly obscure, don t know why they named it The Kmplayer when there already was a Kmplayer, or maybe it s the other way around, either way, the one without the The is much more well known.

Yeah, it was a mistake. I meant decoder. I only knew about one KMplayer though. MPC-HC works for me well and its close connection with ffdshow helps.

Well, what about ffdshow. Could that do what Cyberlink does, or not.

alexeysp

I already have an Auzentech Prelude though

Why don t you use the virtual surround settings then. I m not sure about the exact details, but basically you should set the speakers configuration to 5.1 or 7.1 in the Windows control panel and to Headphones in the Creative control panel, and enable CMSS. Then just use ffdshow to decode the multichannel streams without downmixing. With this setup all the downmixing job should be performed automatically by the soundcard drivers.

Ffdshow also has lots of downmixing options built-in, including some sort of virtual spatialization filter. Don t know how good or bad it is compared to Dolby Headphone though.

I just tried it, and I clicked on the speaker icons in the windows control panel to test it, and it s not at all what Dolby headphone does. Front right and back right sound pretty much the same, no sense of space at all.

Is that what the virtual spatialization filter is for.

Maybe I should try and find which decoders dolby headphone appears in

Yeah, CMSS has NOTHING on Dolby Headphone, that s why I mentioned the X-Meridian. DTS Surround Sensation available now on TotalMedai Theatre 3 is good too though, but Arcsoft stopped letting their decoders being used outside of their program a while ago. ffdshow doesn t offer DH unfortunately.

I think you should try with the actual movies, maybe you ll find it sufficient.Is that what the virtual spatialization filter is for.

You only need one of them active, either CMSS-3D or ffdshow spatializer. If neither will sound good enough for you, then I guess PowerDVD or WinDVD are the only choices left.

Well, I ended up fixing the problem like so: installed PowerDVD9 don t think the version really matters, went to its install directory, copy pasted the entire audio filter folder into a different place, uninstalled this piece of shit program, and am now much happier for it.

Actually, I m kind of embarassed that I didn t think to do this sooner; I ve used decoders by opening them out of folders instead of some software list before, most notably with MPC s decoder, and I tried doing it on the specific file for the cyberlink audio decoder, but it didn t have any of the extras like dolby headphone. I need to take the whole folder instead, and so I did and now everything is working great.

Well, almost everything; the decoder can t decode AAC and AC3 as stated before, for whatever reason and I m not the only one with that problem, so I have my player switch both AC3 and AAC to LPCM output which it CAN decode, as I think I said before which was suggested to another person having the problem. Now this works just fine with AC3 as far as I can tell but for some reason it has a weird problem with AAC. I m watching a rip of Predator and the 5.1 has Arnold s voice coming more out of the right speaker while he s to the left on-screen, and it happens with a lot of other stuff too. It could be my player, or the decoder, I honestly don t know. Hell, maybe it s the rip; any way to check it. Like an AAC sound file player that separates each channel. I could then just listen to each channel outside of all this media player nonsense and see if the sound is in the right channels in the audio file or if it was just a poor rip by someone.

I think I ll also try separating the video and the audio, converting the audio to AC3, and then putting them back together and seeing if that will fix it.

Hmm

Do you know which build you installed. PowerDVD also stopped letting people use their decoders outside of the program, but I think someone else mentioned that the last build didn t do it.

Oh and that gives me an idea: andy, you say that arcosft doesn t allow their decoders to be used in other programs, but how is this enforced. Might I, by any chance, find the decoder file in the program s installation directory. Or is it built into the program. IF so, has anyone tried taking it out. I can t imagine that it d be too hard for someone who knows what they re doing.

Or maybe the decoder is built from the ground up to only work with Arcsoft software.

Let me know.

Alexey, thanks for the help but at this point I m not going to settle for less.

When did it do that. I ve been able to use PowerDVD decoders for 2-3 years now, though I didn t regularly update the program. Right now I can confirm that version 9 build 20XX can t remember the 2 last numbers has the folder and I copied it and am using the decoder directly from the folder, but I was also able to have my media player find it through software means. Same thing for either version 25XX or 23XX, can t remember which I had installed before this one.

But I m pretty sure they d all work.

How do they stop other programs from using the decoder. If it s still in the program folder as a separate file, a decent media player should be able to just use the decoder file.

Oh, and how is WinDVD. I have vague memories of trying it and being dissatisfied compared to Cyberlink s.

Maybe I ll try and install it again.

Well WinDVD is terrible, I m sure there s some way to make it work, but even reading about how to enable the use of the features like dolby headphone from its decoder makes me want to forget about it. I tried dolby headphone within the player itself, and it wouldn t do it properly either. Not to mention that even enabling it in the player was annoying, half the time when I started the player, the option wouldn t come up, and then I restarted it and it would. What triggers the option being available. Hell, I don t even want to know anymore.

Sigh

I guess I ll try an earlier version of PowerDVD next. It did have dolby headphone implementation prior to version 9, right.

And there isn t a difference between cyberlink s dolby headphone usage and windvd s right. Someone claimed that windvd s was better, though it was from a few years ago.

Last Edit: 21 February, 2010, :51 PM by ChorniyVolk

SoI m going to go ahead and kill myself.

I ran the program in compatibility mode and set it to work as if in Windows 7. That s it, there s just some problem with the kmplayer using cyberlink s audio decoder in windows 7, or something.

I should probably let them know, maybe they ll fix it soon.

Still doesn t explain that cyberlink freezing on startup crap, but oh well, guess they re not connected.

Well more knowledgeable people than I at the HT forum at AVSforum have tried, in vain with TMT3. You could do it before, just register the. ax file or dlls, but now the files have the same names, but they just don t connect outside of TMT3.

I got WinDVD 2010 for 30, I don t think I would have bought it for much more than that. A bunch of us with ATI 5000 cards bought it cause someone discovered that the totally un-advertised though much sought-after feature of bitstreaming the HD codecs from bluray worked with WinDVD. This came before even PowerDVD 9 started supporting it who unlike Corel, built a lot of hype around it. But that said, without bitstreaming it is very buggy. It has Dolby Headphone, but they make the same stupid mistake of downmixing to stereo before applying DH, so it s as good as nothing unless you re listening to stereo tracks. It can t decode anything 7.1, and forced autoplay is always annoying as hell. They don t let you use their decoders either AFAIK.

BTW I ve never had a problem with PowerDVD s Dolby Headphone implementation, since versions 6, 7.3 and 8.

What do you mean, same stupid mistake. Who else makes this stupid mistake of downmixing to stereo. Cyberlink.

Hmm, funny, cyberlink s audio decoder won t decode the multichannel aac audio on my rip of Predator. It does however work on the 2 channel AAC of A Goofy Movie that I have no explanation need, movie rocks.

Here is their info, can one of you guys explain why it works for Goofy but not Predator, or does the explanation not lie here.

Predator:

Format : AAC

Format/Info : Advanced Audio Codec

Format version : Version 4

Format profile : LC

Format settings, SBR : Yes

Format settings, PS : No

Codec ID : A_AAC

Duration : 1h 46mn

Channel s : 6 channels

Channel positions : Front: L C R, Rear: L R, LFE

Sampling rate : 48.0 KHz

Resolution : 16 bits

Title : ND HE-AAC 6ch

Language : English

A Goofy Movie:

Format settings, SBR : No

Duration : 1h 14mn

Channel s : 2 channels

Channel positions : L R

EDIT: I think it s the Format settins, SBR part, because I have another movie with AAC audio that works fine and it shares Goofy s No instead of Predator s Yes. However, it also only has 2 channels, so either it s that or it s the more than 2 channel that is causing it.

Last Edit: 22 February, 2010, :06 AM by ChorniyVolk

What do you mean, same stupid mistake. Who else makes this stupid mistake of downmixing to stereo. Cyberlink.

Damn, my fault. I was gonna mention again the Plantronics gaming headphone with DH. That s the one that makes the same mistake. I haven t tried PowerDVD 9 I had it briefly then returned it cause it was crap, but I ve been a big fan of DH pretty much thanks to Cyberlink. Worked fine with PDVD 6, 7.3 and 8 except for TrueHD in some builds of 7.3 and 8, don t remember if they fixed it.

Last Edit: 22 February, 2010, :24 AM by andy o

One other thing, is the audio decoder of 6 and 7 the same as 9. Correct me if I m wrong, but I tried 8 s, and it s pretty much exactly the same as 9 s, so my AAC problem remained. I was thinking of using an even older version s decoder and if it works properly, use it exclusively for the very rare occasion that I have a movie with AAC surround sound audio.

They re probably not the same since 9 has to support bluray, right.

CMI9880/8CH Azalia Audio Codec 8 channel DACs with SNR 95dB. Capabilities: 192 / 96 / 48 kHz with 24 / 20 / 16 bits 4 channel ADCs with SNR 85dB.

Dolby creates audio, visual, and voice technologies for cinemas, home theaters, PCs, mobile devices, and games.

Dolby Digital Prologic 2 vs Dolby digital 5.1

Dolby TrueHD is a lossless multi-channel audio codec developed by Dolby Laboratories which is used in home-entertainment equipment such as Blu-ray Disc players and A.

DTS Headphone:X is a Home Theater in your Pocket HTiP solution for mobile audio that faithfully reproduces the home theater surround sound experience, up to 11.1.

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