Bit exact audio in Reclock without any resampling

[leeperry]

he was definitely talking about your bit-perfect Reclock DLL....and he was depicting what it actually does from what you told me ?!

at that time you answered him that the sampling rate was set once and for all(eg. 48@46080) and wasn't dynamic during the movie....but you now just said the opposite

I don't believe your bit-perfect DLL could keep the A/V sync intact if it only changed the sampling rate ONCE at the beginning of the movie...so now that you're mentioning that it changes the playback speed over time to follow the video PLL drift, it makes a lot more sense.

but it's still what madshi said

and about the rabbit stuff, I understand that Reclock will slow down 48@46080 then resample it back to 48 to make the sound card happy...so I also don't understand the explanation you just gave me 2 posts earlier :disagree:

but you know what...no biggy! I already know too much about Reclock than I should as a end-user.

the worst is Jong, he's been talking too often for too long w/ Beliyaal..I can tell you that

 

[yesgrey3]

at that time you answered him that the sampling rate was set once and for all(eg. 48@46080) and wasn't dynamic during the movie....but you now just said the opposite

No I haven't. My modded dll it's not dynamic during the movie. Only reclock's standard dll is dynamic during the movie.

I don't believe your bit-perfect DLL could keep the A/V sync intact if it only changed the sampling rate ONCE at the beginning of the movie...

If you don't believe, just try it. As I said, in practice, it works pretty good.

and about the rabbit stuff, I understand that Reclock will slow down 48@46080 then resample it back to 48 to make the sound card happy...so I also don't understand the explanation you just gave me 2 posts earlier :disagree:

No. reclock does not work like that. Reclock works like I have posted. Trust me, I have looked inside resampler.dll code and ran some tests that showed my description is correct.

 

[zipi]

Thanks a lot for this one yesgrey3, I will try it.

 

[leeperry]

@yesgrey3 : OK thanks the explanations, I'll look into it 8)

BTW, for ppl worried about resampling, there's some third party audio drivers for USB soundcards : http://www.usb-audio.com/

many cards are supported, it ditches the manufacturer drivers and puts some bit-perfect MME+ASIO drivers w/ lot of cool options(many sample rates my M-Audio ASIO drivers didn't support), dithering if you need SRC, etc..

too bad it won't do automatic clock selection(checking 44.1/48/96 manually gets odd, and it can't be set in the registry) and won't offer WDM bitperfect drivers, but I've sent an email to their tech support

maybe they could even allow variable sample rate

 

[leeperry]

ok my lazy ass has finally tried your DLL :clap:

now, I *have* to get it working, no matter what it takes

I've tried 23.976@48Hz w/ my M-Audio Audiophile USB bit-perfect MME drivers, and the sound is just great!

HR's jitter seems more stable, the SQ is pristine...just great!

too bad it glitches up from time to time....I still got 2 tricks up my sleeve :
-the Gina24 has bitperfect WDM drivers, so I could try that...and if it's still not OK, I could also try to enable the "hardware resampling" in Reclock
-get a Gina3G, that natively supports variable sample rates.

does your DLL even care about timestamps? what it does is not clear to me TBH..

so if I run 23.976@48.000Hz, it will accelerate the video to 24fps and play the audio at 48048Hz? that's it? and depending on what EXACT refresh rate Reclock measures, it might be 48056 or 48042 or sumthing like that? no dynamic adaptation during the movie whatsoever?

how can I make sure that it's working? if I set Reclock to 2*frame rate, the sound will run at double sampling freq and have twice faster pitch?

you don't have to check "slave to audio clock" but must leave "auto" checked...right?

 

[leeperry]

hummm, are you sure your DLL tells the audio drivers about the funky sample rate ? like 46080 or 48048 ?

I know you rely on your RME drivers where you change it manually, apparently Echo supports it out of the box(even on the Gina24 from what their techsupport tells me) but if your DLL doesn't tell the drivers about the requested sample rate....that'll be a no go

 

[leeperry]

apparently your DLL doesn't tell the audio drivers that 23.976@25 needs to be played at 50Khz



so your fix is indeed RME-only as I understand it, instead of resampling it simply copies the original audio data...w/ the original sample rate

you rely on your manual sample rate override in the RME drivers to pitchshift it...but even if your audio drivers allow any funky sample rate you'd like, it will not work :doh:

their support told me that it wasn't supported to force it in the drivers, but if the app asks for it...it will do it.

PS: from Echo's techsupport :

you say the Gina3G has a "Variable sample rate feature lets you select any sample rate between 25kHz - 100kHz"...so playing 46080/48048Hz should work with Reclock in "PureWave" bitperfect mode on XP?

- It should!

also on the Gina24?

- Yes.

 

[yesgrey3]

you don't have to check "slave to audio clock" but must leave "auto" checked...right?

Yes.

hummm, are you sure your DLL tells the audio drivers about the funky sample rate ? like 46080 or 48048 ?

No. My dll only bypasses the resampling, nothing more. It will only work if we manually set the correct clock in the soundcard drivers. RME allow it, I'm sure other soundcards would also allow it.

so your fix is indeed RME-only as I understand it, instead of resampling it simply copies the original audio data...w/ the original sample rate

Yes, it works like that, but is not RME only. Any soundcard that could work with a 46080Hz or 48048Hz clock should work too.

their support told me that it wasn't supported to force it in the drivers, but if the app asks for it...it will do it.

Well, it would be very easy for them to allow it at the drivers level. RME does it.
It's not possible to set the clock frequency in the resampler.dll, it must be set inside reclock. I've requested it to James, but unfortunatelly he doesn't have the time to do it, so your better option is requesting the Gina support to add the manual setting to the drivers, or at least a registry key for it, or you could always reconsider and buy a RME soundcard...

 

[leeperry]

ok, thanks for the confirmation! well James has told me that it was a "stupid question"

ah well, Reclock will resample even if your soundcard can play any sample rate in a bitperfect fashion(and it doesn't support ASIO either), HR will never drop frames *only* if you "catch" the VSYNC properly....using an HTPC is an everyday struggle :bang:

Echo have directed me to their drivers SDK, so you could change the sample rate on the fly : http://www.echoaudio.com/Downloads/Developer.php

and I've tried to play at 47.952Hz w/ your DLL, but the audio is too slow...I'm afraid I can hear 0.1% slow down, it sounds like a very old Revox deck that doesn't play fast enough

 

[yesgrey3]

Echo have directed me to their drivers SDK, so you could change the sample rate on the fly : http://www.echoaudio.com/Downloads/Developer.php

Sorry, but that link is for creating drivers to their soundcard. I have not the skills for doing it. It should be very easy and simple for them just creating a registry key where you could set the clock frequency you want. Ask them this, maybe they will do it.

 

[leeperry]

sorry, I meant "you" in a rhetorical way

let's hope James will be OK to add that feature you suggested him, 100% bitperfect 23.976@48Hz on any capable soundcard(not just RME/Lynx as it is atm) would be really awesome :rock:

and for the RME/Lynx peeps that currently override the sample rate manually in their audio drivers, they wouldn't have anything to do anymore...it would be fully automatic 8)

and you can get a second hand Gina24 for quite cheap(or a brand new Gina3G/AudioFire 2), so 100% bitperfect would finally be accessible to the mass

maybe some even cheaper sound cards would allow variable sample rate too!

 

[James]

sorry, I meant "you" in a rhetorical way

let's hope James will be OK to add that feature you suggested him, 100% bitperfect 23.976@48Hz on any capable soundcard(not just RME/Lynx as it is atm) would be really awesome :rock:

and for the RME/Lynx peeps that currently override the sample rate manually in their audio drivers, they wouldn't have anything to do anymore...it would be fully automatic 8)

and you can get a second hand Gina24 for quite cheap(or a brand new Gina3G/AudioFire 2), so 100% bitperfect would finally be accessible to the mass

maybe some even cheaper sound cards would allow variable sample rate too!

I don't think there is an easy, generic way to do this.

 

[leeperry]

I don't think there is an easy, generic way to do this.

that's what the Echo Tech Support told me :

ok I've spoken w/ the Reclock guys, I would need to force the sample rate to 46080 or 48048 in the Echo drivers, like on the RME : http://www.image-load.eu/out.php/i159642_rme.jpg

- We don't support this, as of now.

I guess that's not possible?

- Not right now.

funny that you say that the Gina3G has a "Variable sample rate feature that lets you select any sample rate between 25kHz - 100kHz" then....so it's not true ?!

- Not without a third party software with variable sample rate....

I didn't study the DS white papers on the m$ website, but if you could "try" to force the new sampling freq for WASAPI Exclusive/KS, that'd fill everyone's needs...

the resampler in Reclock ruins the SQ, like lossy DTS/AC3 ruins the SQ of lossless LPCM...so maybe a few lines of code in Reclock would allow fully bit-perfect pitchshift :agree:

if you're OK to try for KS first, we'll be happy to try it

the Gina24 7.3 XP/Vista32&64 drivers PDF says "Improved Kernel Streaming framing for better Vista and DirectKS support", and they also offer bit-perfect WDM drivers on XP and Vista(and WaveRT too)!

http://www.microsoft.com/whdc/archive/directks.mspx

Using the DirectKS approach results in exclusive access to the audio device, which can break many aspects of the user experience, including disabling warning alert sounds and loss of interoperability with other audio applications.

 

[yesgrey3]

I don't think there is an easy, generic way to do this.

My suggestion of try the desired clock, then, if it fails, just set to the audio source clock, seems to be easy and generic, unless something else is escaping me...

 

[leeperry]

honestly, I don't think our MME drivers are bit-perfect....mine definitely aren't, even though the Windows volume slider doesn't work!

http://msdn.microsoft.com/en-us/library/ms790010.aspx

An audio stream that is output by the waveOut API always passes through KMixer, even if the audio device provides hardware-accelerated mixing.

and yours might very well be mono-client, I've read tons of m$ white papers....Waveout goes through KMixer no matter what! I wonder what RME would have to say about that..

and I dearly hope that James will be able to offer 96/192KHz resampling instead of the original rate....because it will drastically improve the resampling(more frequency headroom, less distortion) and my soon-to-arrive Asus Xonar Essence STX soundcard doesn't do anything funky on ASIO or 96/192Khz KS....the rest is resampled to the sample rate set in the drivers

if one day I get bit-perfect Reclock and foobar, this will have been a long struggle...I can tell you that :doh:

my current M-Audio Audiophile USB has fully working KS drivers, but only on Vista(even though the drivers share the same .exe for both OS)...on XP I'm stuck w/ ASIO, that Reclock won't support...ever

 

[James]

@yesgrey3 & leeperry:

Please have a look at ReClock 1.8.4.3

New experimental registry values:

DWORD BypassResampler (0 or 1, default 0)

Bypasses resampler, should do the same as yesgrey3's non-resampling dll
Note, properties still show the samplerate the resampler *would have used*
This value is checked whenever the reclock filter is loaded (usually once)

DWORD ForceSampleRate ( 0=off, frequency in kHz, default 0)

Sets a fixed rate when opening Wave/DS/KS/Wasapi audio.
This value is checked whenever the audio is opened.

Have fun playing...

 

[leeperry]

awesome, thank you James!

will it also allow to use the regular Reclock resampling, but w/ 96/192KHz?

 

[leeperry]

ForceSampleRate (in kHz) : I think you meant "Hertz" and not "KHz" ?

I've tried to set it to 96, and I don't get any audio...w/ 96000 I get stuttering accelerated sound(my audio drivers does say "streaming at 96KHz"), whatever Waveout or DS(I left BypassResampler disabled).

24/96 audio works fine in Waveout/DS

PS: OTOH when set to "48048" + BypassResampler=1, it sounds OK in Waveout

 

[James]

ForceSampleRate (in kHz) : I think you meant "Hertz" and not "KHz" ?

oh yes, of course....

 

[James]

hopefully it will also allow to use the regular Reclock resampling, but w/ 96/192KHz :clap:

What?
I don't think so...