The Inconvenient Truth about SPDIF Input! - Page 2 - AVS Forum | Home Theater Discussions And Reviews
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post #31 of 199 Old 10-25-2009, 12:59 PM - Thread Starter
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Hey, I'm writing this post to address some of the comments people have made previously in this thread. I am also bumping the thread again because I have added various additional updates to the main post.

Quote:
Originally Posted by doctorj46920 View Post

First of all, I want to straighten out a mis-conception shown in this thread. The SPDIF audio will always appear as just 2 16-bit PCM channels. Dolby Digital and DTS are encoded as compressed data within these two channels. A more detailed explanation can be found on the AC3Filter site, but just know that your SPDIF input *should* be 2 channels.

Not true! Yes, you are correct that DD/DTS streams are COMPRESSED into a 2 channel, 16-bit PCM stream. However, as part of this stream, there is a bit that is set which indicates to an input device (like a receiver) that the signal is either STANDARD 2 channel PCM or a PCM wrapped AC3 stream. Some sound cards (like Realtek) will actually read this bit and inform you of the stream type (see above). However, most likely to avoid any legal issues, the chip doesn't pass this information to directshow. If it did, the "MediaSubtype" field would say "MEDIASUBTYPE_AC3" instead of "MEDIASUBTYPE_PCM". The problem is that decoders like ffdshow use this field to determine the method to use to decode the input stream, so if the field says "MEDIASUBTYPE_PCM", then ffdshow is going to "decode" it as a standard 2 channel PCM signal.

Quote:
Originally Posted by doctorj46920 View Post

Using Graph Edit, I connected the Sabrent's WDM Streaming Capture Device to AC3Filter version 1.51a. Set the output format of AC3Filter to "3/2+SW 5.1 Channel".

It DOES seem from your pictures that this device MAY be able to handle what you claim it is handling. However, to make sure, could you go into the properties of the "Sabrent WDM Streaming Capture Device" in graphedit and check the "MediaSubType" field for me? This would tell me for sure if the signal being passed into AC3filter was, in fact, AC3. I am somewhat skeptical about this because the "3/2+SW 5.1 Channel" option in AC3filter has two features to it:
1. It can take a 5.1 signal and pass it to the appropriate channels.
2. It can take a non 5.1 signal and covert it to 5.1 channels.
While your picture of the AC3Filter properties encourages me that, in fact, the signal is being both input AND output as 5.1, I just want to make sure.

Quote:
Originally Posted by doctorj46920 View Post

Now, the only down-side is that the C-Media chip supports SMCS on SPDIF. My Dish Network receiver decodes fine. But I found that when I play a purchased DVD in my Toshiba D-RW2, it apparently sets SMCS enable and I get exactly NOTHING on SPDIF through the CM6206. A rip/copy of the DVD on recordable media works fine.

I can't really speak to this issue. However, the SMCS may actually be C-Media's way of appeasing the RIAA and MPAA by making the input signal "non-copyable". If this is the case, then I am very eager to try out this sound card as it may have found a reasonable solution to the legal issues and maybe the other sound card companies can be made aware of it.

Quote:
Originally Posted by doctorj46920 View Post

Talk about digital rights management getting in the way of legitimate uses!

I couldn't agree with you more!

Quote:
Originally Posted by stranger89 View Post

No offense guys, but this has been known and discussed here for years. Don't bother trying to build a prepro out of a PC unless you like pain.

No offense taken. I know I'm not really saying anything "new" about this issue. I just felt it might be useful to people to have all of the information related to this issue conglomerated into one post. That way people don't have to incessantly search the web like I had to and in the process waste HOURS on trying to find a solution which, to be frank, doesn't really exist.
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post #32 of 199 Old 10-25-2009, 11:38 PM
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Sorry this is not really adding to the discussion, as I'm just a curious observer at this stage...
But I think it would better serve this thread's intent if you considered renaming it's title.

The current name does not clearly indicate the main focus of this thread...
Which is: "Make your HTPC your AVR too....."

I may add some stuff later, but mainly from a Linux perspective...
And also some stuff in-relation to adding components that are usually considered the domain of an AVR.
i.e. amp, + few other things which escape me right now.
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post #33 of 199 Old 10-26-2009, 02:47 AM
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As part of DScaler 5 I wrote a filter to look at the incoming stream and detect either ac3 or dts and dynamically switch the output to the correct type. Worked well enough and detecting the stream type automatically is relatively straightforward.

With DirectShow I also found the issue of at least a .5 second delay that made this unusable in practice, there are other possible solutions based on exclusive mode, how much interest is there in a solution for this?

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post #34 of 199 Old 10-26-2009, 11:31 AM
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That tell you?

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post #35 of 199 Old 10-26-2009, 12:56 PM
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Quote:
Originally Posted by JohnAd View Post

As part of DScaler 5 I wrote a filter to look at the incoming stream and detect either ac3 or dts and dynamically switch the output to the correct type. Worked well enough and detecting the stream type automatically is relatively straightforward.

With DirectShow I also found the issue of at least a .5 second delay that made this unusable in practice, there are other possible solutions based on exclusive mode, how much interest is there in a solution for this?

John

I am very interested and I am sure there are others to. A solution for this would be awesome and open some real possibilities.
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post #36 of 199 Old 10-26-2009, 01:30 PM
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Did anyone investigate on (professional) PCI(-Express) devices that could do the decoding in hardware? So instead of searching for a soundcard that will properly expose the spdif signal to directshow, search for a device doing it in hardware (eg with special DSPs for that purpose). That could be either a dolby/dts receiver in PCI format or a soundcard able to do that.
I've heard that the Creative Soundblaster Extigy is able to decode spdif input on the fly and in hardware, but that's an external soundcard which would take the whole idea of this thread ad absurdum.
Which Soundchip / dedicated Soundcard manufacturers do you know at last?
There's Creative Technology and its professional department E-MU, which is probably the most prominent dedicated card manufacturer.
The only other Card manufacturers with own chips I know are ASUS and Terratec.
Then there's realtek, c-media, via and intel who build onboard chips after Intels AC'97 or HD-Audio Specification.
Have I missed anyone?
None of them gives any hint on capabilities of decoding digital multichannel sound when you read the product description/technical details. But at least Creative seems to answer questions on that topic. (Only hearsay though, haven't tried yet)

Shouldn't that be the preferred way (decoding in hardware)?
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post #37 of 199 Old 10-26-2009, 01:39 PM
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As previously mentioned, the Creative X-FI, Audigy4 and Extigy could do it until Vista drivers arrived... I've heard two schools of thought...
1) Can't be done under the new Vista audio stack
2) Creative didn't want to pay Dolby anymore...

My bet's on 2.

PS.... as I mentioned in post 9 of this thread, not all SPDIF inputs (or their capture drivers?) are created equal....

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post #38 of 199 Old 10-26-2009, 02:04 PM
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Quote:
Originally Posted by Mastacheata View Post

Shouldn't that be the preferred way (decoding in hardware)?

Software would be a lot more flexible, it opens it up to things like bass management, room correction, delays and so on.

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post #39 of 199 Old 10-27-2009, 07:54 AM - Thread Starter
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Quote:
Originally Posted by JohnAd View Post

As part of DScaler 5 I wrote a filter to look at the incoming stream and detect either ac3 or dts and dynamically switch the output to the correct type. Worked well enough and detecting the stream type automatically is relatively straightforward.

With DirectShow I also found the issue of at least a .5 second delay that made this unusable in practice, there are other possible solutions based on exclusive mode, how much interest is there in a solution for this?

Oh I think there is probably a lot of interest! What method did your filter use to detect the stream? If you notice what I discussed in the main post of the thread, the solution needs to detect the stream in a method other than by accessing the SubType from DirectShow.

Another idea would just be to create a software solution that "emulated" a capture device and just set that SubType to AC3. This way you could still pass the signal to something like ffdshow or AC3filter to decode the audio. I don't think this will fix the delay, but maybe the MPC audio decoder will do it better.

Quote:
Originally Posted by Mastacheata View Post

Did anyone investigate on (professional) PCI(-Express) devices that could do the decoding in hardware? So instead of searching for a soundcard that will properly expose the spdif signal to directshow, search for a device doing it in hardware (eg with special DSPs for that purpose). That could be either a dolby/dts receiver in PCI format or a soundcard able to do that.
I've heard that the Creative Soundblaster Extigy is able to decode spdif input on the fly and in hardware, but that's an external soundcard which would take the whole idea of this thread ad absurdum.
Which Soundchip / dedicated Soundcard manufacturers do you know at last?
There's Creative Technology and its professional department E-MU, which is probably the most prominent dedicated card manufacturer.
The only other Card manufacturers with own chips I know are ASUS and Terratec.
Then there's realtek, c-media, via and intel who build onboard chips after Intels AC'97 or HD-Audio Specification.
Have I missed anyone?
None of them gives any hint on capabilities of decoding digital multichannel sound when you read the product description/technical details. But at least Creative seems to answer questions on that topic. (Only hearsay though, haven't tried yet)

Shouldn't that be the preferred way (decoding in hardware)?

Obviously you haven't read through my main post entirely. Of course hardware decoding would be the preferred method, but currently there aren't ANY sound cards that will work with Vista/Win7 and do hardware (or even software) decoding. As jimwhite said:
Quote:
Originally Posted by jimwhite View Post

As previously mentioned, the Creative X-FI, Audigy4 and Extigy could do it until Vista drivers arrived...

The other sound cards you suggest (Realtek, Via, Intel) are all using the Realtek chipset which has NEVER supported AC3 streams on the SPDIF input.

Other people have also suggested other sound cards that are rumored to work. I have included them (with links) in the "Possible Solutions" section of the main thread. This includes a solution by C-media that I am in the process of trying out myself. I will let you know how it goes.

Quote:
Originally Posted by JohnAd View Post

Software would be a lot more flexible, it opens it up to things like bass management, room correction, delays and so on.

John

Those things could still be accomplished at a chipset level. In fact, D2Audio's recent firmware update for their chipset on the MSI Media Live Diva added exactly those types of manipulations. I agree that software would definitely be more flexible, but a hardware solution would certainly eliminate the lag issue (although this could probably also be addressed with well written software too).
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post #40 of 199 Old 10-27-2009, 08:02 AM - Thread Starter
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Quote:
Originally Posted by jalyst View Post

Sorry this is not really adding to the discussion, as I'm just a curious observer at this stage...
But I think it would better serve this thread's intent if you considered renaming it's title.

The current name does not clearly indicate the main focus of this thread...
Which is: "Make your HTPC your AVR too....."

I thought the title was pretty clear, but you are right, it could certainly be more clear. Unfortunately though, I don't think I can change the title of the thread once it has been posted. Maybe if I was an admin or "super member" I could do it, but alas I am not.

Quote:
Originally Posted by jalyst View Post

I may add some stuff later, but mainly from a Linux perspective...
And also some stuff in-relation to adding components that are usually considered the domain of an AVR.
i.e. amp, + few other things which escape me right now.

Great! Whatever information you can provide to add to the topic! When you say "Linux perspective" are you referring to MythTV? Are you using Ubuntu?
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post #41 of 199 Old 10-27-2009, 08:27 AM
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Quote:
Originally Posted by dadudster View Post

Oh I think there is probably a lot of interest! What method did your filter use to detect the stream? If you notice what I discussed in the main post of the thread, the solution needs to detect the stream in a method other than by accessing the SubType from DirectShow.

I looked at the stream looking for spdif control words and switched the output type based onteh steam type

Quote:
Originally Posted by dadudster View Post

Another idea would just be to create a software solution that "emulated" a capture device and just set that SubType to AC3. This way you could still pass the signal to something like ffdshow or AC3filter to decode the audio. I don't think this will fix the delay, but maybe the MPC audio decoder will do it better.

Won't help, most of the latency comes from the capture and renders stages



Quote:
Originally Posted by dadudster View Post

Those things could still be accomplished at a chipset level. In fact, D2Audio's recent firmware update for their chipset on the MSI Media Live Diva added exactly those types of manipulations. I agree that software would definitely be more flexible, but a hardware solution would certainly eliminate the lag issue (although this could probably also be addressed with well written software too).

Hmmm, I'd think decoding say adding DTS would be hard to do at the chipset level, but a hybrid solution may be possible.

Thinking about this some more, there are also possible clock sync issues with spdif in that I'm not sure all cards will deal with well, also autodetection of sample rate didn't work last time I checked.

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post #42 of 199 Old 10-27-2009, 08:39 AM - Thread Starter
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Bump: New updates to main post.
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post #43 of 199 Old 11-01-2009, 11:16 PM
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Quote:
Originally Posted by dadudster View Post

I thought the title was pretty clear, but you are right, it could certainly be more clear. Unfortunately though, I don't think I can change the title of the thread once it has been posted. Maybe if I was an admin or "super member" I could do it, but alas I am not.

You still can, you just choose "edit" on your 1st post...
then you click "go advanced" then in the "Title" field edit the title and click "save".

Quote:


Great! Whatever information you can provide to add to the topic! When you say "Linux perspective" are you referring to MythTV? Are you using Ubuntu?

Yes & yes
Taking me forever to get all the exact parts I want though, I can be extremely fastidious.
Once I actually start to put everything together I may document a lot of it.
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post #44 of 199 Old 11-02-2009, 03:11 PM
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Quote:
Originally Posted by diablosv View Post

Sorry I really can't see the point of SPDIF-IN especially for AC3, I mean you might as well just play it all on the PC directly anyway.
DVD and even blu-ray drives really don't cost much.

Because the DVR outputs AC3 sound over SPDIF. Eventually, with Win 7 and the new Ceton cablecard, this will become a moot point as it is the only source that cannot easily (cablecard is still iffy, but not much longer) originate in the HTPC.

But the lack of AC3 input has been a vexing problem for those of use determined to stick with an HTPC and amps instead of a receiver. In reality, I think the eventual solution to this problem will be to forget the aged SPDIF input entirely after the Ceton cablecard arrives. Except for those stuck with DirecTV . . .

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post #45 of 199 Old 11-04-2009, 04:59 PM - Thread Starter
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Quote:
Originally Posted by lifespeed View Post

In reality, I think the eventual solution to this problem will be to forget the aged SPDIF input entirely after the Ceton cablecard arrives. Except for those stuck with DirecTV . . .

Hey I like my DirecTV. I don't particularly need my HTPC driving EVERYTHING. Although a DirecTV PCI-e card might be cool, if DirecTV would also provide their GUI (I like the DirecTV front-end/programming guide).
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post #46 of 199 Old 11-05-2009, 08:38 AM
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Quote:
Originally Posted by dadudster View Post

Hey I like my DirecTV. I don't particularly need my HTPC driving EVERYTHING. Although a DirecTV PCI-e card might be cool, if DirecTV would also provide their GUI (I like the DirecTV front-end/programming guide).

Each to their own. I'm not saying you should switch if you really like it, just that it drives some compromises in the HTPC area. Essentially it forces you to have a receiver for surround-sound HDTV instead of soundcard --> amps.

Where I live the cable system is pretty good, so I will eventually have the DVR in the PC once the proper hardware is released. Today, I don't have surround sound from my Comcast DVR because my HTPC can't (easily) accept DD over SPDIF. I'm not going to try and fix SPDIF, either, as I will soon have all my sources inside the HTPC.

Really, SPDIF is a dinosaur, but is kept alive by issues like your desire for DirecTV.

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post #47 of 199 Old 11-05-2009, 07:26 PM
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Quote:
Originally Posted by dadudster View Post

Not true! Yes, you are correct that DD/DTS streams are COMPRESSED into a 2 channel, 16-bit PCM stream. However, as part of this stream, there is a bit that is set which indicates to an input device (like a receiver) that the signal is either STANDARD 2 channel PCM or a PCM wrapped AC3 stream. Some sound cards (like Realtek) will actually read this bit and inform you of the stream type (see above). However, most likely to avoid any legal issues, the chip doesn't pass this information to directshow. If it did, the "MediaSubtype" field would say "MEDIASUBTYPE_AC3" instead of "MEDIASUBTYPE_PCM". The problem is that decoders like ffdshow use this field to determine the method to use to decode the input stream, so if the field says "MEDIASUBTYPE_PCM", then ffdshow is going to "decode" it as a standard 2 channel PCM signal.


It DOES seem from your pictures that this device MAY be able to handle what you claim it is handling. However, to make sure, could you go into the properties of the "Sabrent WDM Streaming Capture Device" in graphedit and check the "MediaSubType" field for me? This would tell me for sure if the signal being passed into AC3filter was, in fact, AC3. I am somewhat skeptical about this because the "3/2+SW 5.1 Channel" option in AC3filter has two features to it:
1. It can take a 5.1 signal and pass it to the appropriate channels.
2. It can take a non 5.1 signal and covert it to 5.1 channels.
While your picture of the AC3Filter properties encourages me that, in fact, the signal is being both input AND output as 5.1, I just want to make sure.

For whatever reason I am unable to get any property pages for the Sabrent WDM Streaming Capture Device.

Here is the "Decoder Info" from AC3Filter. AC3Filter is quite clearly decoding the AC3 encoded stream in the 2 channel SPDIF (into 5.1 channels suitable for passing into the SRS Audio Sandbox).

This same setup also works with DTS encoded streams.

This is the real McCoy - it works. I also attached a picture of the AC3Filter Mixer showing the real-time channel levels.

---
Input format: PCM16 2/0 (stereo) 48000
User format: PCM Float 3/2.1 (5.1) 0
Output format: PCM Float 3/2.1 (5.1) 48000

Decoding chain:
(PCM16 2/0 (stereo) 48000) -> Detector -> (SPDIF 3/2.1 (5.1) 48000) -> Despdif -> (AC3 3/2.1 (5.1) 48000) -> Decoder -> (Linear PCM 3/2.1 (5.1) 48000) -> Processor -> (PCM Float 3/2.1 (5.1) 48000) -> Dejitter -> (PCM Float 3/2.1 (5.1) 48000)

Filters info (in order of processing):

Detector:
-

Despdif:
-

Decoder:
Stream format: AC3 3/2.1 (5.1) 48000Hz
Bitstream type: byte stream
Frame size: 1792
Samples: 1536
Bitrate: 448kbps
SPDIF stream type: 0x1
Frame interval: 1792
Actual bitrate: 448kbps
AC3
speakers: 3/2.1 (5.1)
sample rate: 48000Hz
bitrate: 448kbps
stream: 8 bit
frame size: 1792 bytes
nsamples: 1536
bsid: 8
clev: -3.0dB (0.7071)
slev: -3.0dB (0.7071)
dialnorm: -27dB
bandwidth: 14kHz/20kHz

Processor:
(Linear PCM 3/2.1 (5.1) 48000) -> Input levels -> (Linear PCM 3/2.1 (5.1) 48000) -> Input cache -> (Linear PCM 3/2.1 (5.1) 48000) -> SRC -> (Linear PCM 3/2.1 (5.1) 48000) -> Mixer -> (Linear PCM 3/2.1 (5.1) 48000) -> Bass redirection -> (Linear PCM 3/2.1 (5.1) 48000) -> Equalizer -> (Linear PCM 3/2.1 (5.1) 48000) -> Dither -> (Linear PCM 3/2.1 (5.1) 48000) -> AGC -> (Linear PCM 3/2.1 (5.1) 48000) -> Delay -> (Linear PCM 3/2.1 (5.1) 48000) -> Output cache -> (Linear PCM 3/2.1 (5.1) 48000) -> Output levels -> (Linear PCM 3/2.1 (5.1) 48000) -> Linear->PCM converter -> (PCM Float 3/2.1 (5.1) 48000)

Dejitter:
-

---
LL
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post #48 of 199 Old 11-05-2009, 09:25 PM
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Quote:
Originally Posted by dadudster View Post

I can't really speak to this issue. However, the SMCS may actually be C-Media's way of appeasing the RIAA and MPAA by making the input signal "non-copyable". If this is the case, then I am very eager to try out this sound card as it may have found a reasonable solution to the legal issues and maybe the other sound card companies can be made aware of it.

SCMS (Serial Copy Management System) was absolutely devised due to the RIAA. It was originally used for DAT tape, and I believe I recall reading it was written by Toshiba, so no wonder my Toshiba DVD player enforces it. One little bit in the TOSLINK stream prevents the C-Media IC from passing anything through to the record pin. It is difficult (if not impossible) to find a PC TOSLINK input interface that does not support SCMS.

BUT... and this is a VERY exciting but...

I have a new purchase. The $99 BestBuy Insignia NS-BRDVD3 Blu-Ray player with Netflix streaming. In addition to spectacular quality Netflix streaming... it has one VERY interesting audio feature. When you set the Digital Output to "Bitstream Mixed" the player will internally transcode/decode all audio to DTS-ES output on the TOSLINK! With NO SCMS! So no more issue with the Sabrent blocking the SPDIF and turning it to silence (the player decodes the Blu-Ray HD audio formats too, which is cool).

NOTE: When using DTS input I found I must uncheck "Restrict SPDIF sample rate" in AC3Filter, otherwise it does not detect the DTS stream and you get to hear the raw PCM "noise" instead.

Hmmm... wonder if I can decode that back channel (6.1)?

AC3Filter Decoder Info (version 1.63b):
Input format: PCM16 2/0 (stereo) 48000
User format: PCM Float 3/2.1 (5.1) 0
Output format: PCM Float 3/2.1 (5.1) 48000

Decoding chain:
(PCM16 2/0 (stereo) 48000) -> Detector -> (SPDIF 3/2.1 (5.1) 48000) -> Despdif -> (DTS 3/2.1 (5.1) 48000) -> Decoder -> (Linear PCM 3/2.1 (5.1) 48000) -> Processor -> (PCM Float 3/2.1 (5.1) 48000) -> Dejitter -> (PCM Float 3/2.1 (5.1) 48000)
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post #49 of 199 Old 11-17-2009, 12:10 PM
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Yes but I still don't think that BD player allows us to retrieve, decode, and play the AC3 5.1 signal on our PC from other devices such as an Xbox 360.
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post #50 of 199 Old 11-17-2009, 12:13 PM
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Originally Posted by doctorj46920 View Post

For whatever reason I am unable to get any property pages for the Sabrent WDM Streaming Capture Device.

Here is the "Decoder Info" from AC3Filter. AC3Filter is quite clearly decoding the AC3 encoded stream in the 2 channel SPDIF (into 5.1 channels suitable for passing into the SRS Audio Sandbox).

This same setup also works with DTS encoded streams.

This is the real McCoy - it works. I also attached a picture of the AC3Filter Mixer showing the real-time channel levels.

---
Input format: PCM16 2/0 (stereo) 48000
User format: PCM Float 3/2.1 (5.1) 0
Output format: PCM Float 3/2.1 (5.1) 48000

Decoding chain:
(PCM16 2/0 (stereo) 48000) -> Detector -> (SPDIF 3/2.1 (5.1) 48000) -> Despdif -> (AC3 3/2.1 (5.1) 48000) -> Decoder -> (Linear PCM 3/2.1 (5.1) 48000) -> Processor -> (PCM Float 3/2.1 (5.1) 48000) -> Dejitter -> (PCM Float 3/2.1 (5.1) 48000)

Filters info (in order of processing):

Detector:
-

Despdif:
-

Decoder:
Stream format: AC3 3/2.1 (5.1) 48000Hz
Bitstream type: byte stream
Frame size: 1792
Samples: 1536
Bitrate: 448kbps
SPDIF stream type: 0x1
Frame interval: 1792
Actual bitrate: 448kbps
AC3
speakers: 3/2.1 (5.1)
sample rate: 48000Hz
bitrate: 448kbps
stream: 8 bit
frame size: 1792 bytes
nsamples: 1536
bsid: 8
clev: -3.0dB (0.7071)
slev: -3.0dB (0.7071)
dialnorm: -27dB
bandwidth: 14kHz/20kHz

Processor:
(Linear PCM 3/2.1 (5.1) 48000) -> Input levels -> (Linear PCM 3/2.1 (5.1) 48000) -> Input cache -> (Linear PCM 3/2.1 (5.1) 48000) -> SRC -> (Linear PCM 3/2.1 (5.1) 48000) -> Mixer -> (Linear PCM 3/2.1 (5.1) 48000) -> Bass redirection -> (Linear PCM 3/2.1 (5.1) 48000) -> Equalizer -> (Linear PCM 3/2.1 (5.1) 48000) -> Dither -> (Linear PCM 3/2.1 (5.1) 48000) -> AGC -> (Linear PCM 3/2.1 (5.1) 48000) -> Delay -> (Linear PCM 3/2.1 (5.1) 48000) -> Output cache -> (Linear PCM 3/2.1 (5.1) 48000) -> Output levels -> (Linear PCM 3/2.1 (5.1) 48000) -> Linear->PCM converter -> (PCM Float 3/2.1 (5.1) 48000)

Dejitter:
-

---

Just to be clear, would this allow us to decode and play AC3 5.1 on our PC from other devices such as the XBox 360 or PS3 through S/PDIF? If so, does there seem to be any audio lag?
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post #51 of 199 Old 11-17-2009, 02:21 PM
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The latest Creative drivers for Windows 7 say, "Dolby® Digital and DTS® decode re-established for sound cards that included decoding in their Windows XP drivers." I don't have an SPDIF source so I can't check the decoding on the input. Maybe somebody else can check this.

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post #52 of 199 Old 11-17-2009, 11:21 PM
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Thanks, but I don't care for the sound qaulity of the Creative cards. Even their best card doesn't compare with the Asus Xonar HDAV1.3, so I'd really like to find a solution that doesn't involve using a Creative card.
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post #53 of 199 Old 11-18-2009, 08:28 AM
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Quote:
Originally Posted by avmjt View Post

Thanks, but I don't care for the sound qaulity of the Creative cards. Even their best card doesn't compare with the Asus Xonar HDAV1.3, so I'd really like to find a solution that doesn't involve using a Creative card.

Good luck !!

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post #54 of 199 Old 12-13-2009, 10:37 PM - Thread Starter
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bump: new title
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post #55 of 199 Old 02-04-2010, 05:30 PM
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Quote:
Originally Posted by avmjt View Post

Just to be clear, would this allow us to decode and play AC3 5.1 on our PC from other devices such as the XBox 360 or PS3 through S/PDIF? If so, does there seem to be any audio lag?

So far, I've been successful decoding DD and DTS from my PS3 and PS2 via toslink using a similar setup (I described my setup in a post in the first page of this thread). I took the HTO Striker card I had mentioned (the one that could decode correctly in my XP machine but not in my Win7 machine) out of the new Win7 PC and I put it back in my old XP machine. Voila, it still decodes AC3 and DD over spdif in from the PS3 and PS2. What I cannot get it to do is to decode DD from my DirecTV receiver. Anybody know why this is happening? Everytime I select a DD track in DirecTV, there is silence... no raw compressed PCM, no static; just silence. Is there a way to fix this? Maybe someone knows how DD is transmitted over toslink from a DirecTV receiver
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post #56 of 199 Old 02-04-2010, 09:44 PM
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Quote:
Originally Posted by dadudster View Post

The reasons we want to take on this challenge are summed up here:
  • Because we don't want another piece of hardware sitting in our media rack (or ANOTHER remote).
  • Because we don't want to spend the extra money on a receiver.
  • Because a computer SHOULD be able to handle it.
[/i]
.

Question 1: If you are trying to cut down the pieces in your rack, what are you inputting sound from? Only thing that I think a PC could not 85% replace is the Wii. Most PS3 and Xbox games end up on the PC with few exception. Not sure what else couldn't be incorporated. Older consoles could be emulated.

Question 2: Why should a PC be able to handle it? Most higher end audio devices need some type of amp. A major part of a receiver is the internal Amp. Anyone who has used an amp knows that these thing can get incredibly hot which does not work well with a PC. I know my Onkyo gets a heck of alot hotter than my HTPC which is why I have my HTPC under the Onkyo.

I understand the idea of eliminating down to one unit, but a PC doesn't always do everything else better than a SA. Sometimes yes.... sometimes no.

Should we decide that they should have projector addons built into a PC? In the end, a reciever acts as the display unit for your sound.

And yes, I think it does come down to legal issues. I would expect the studios (music and movie) to allow a direct audio copy to be allowed legally so this protection needs to be built in for their own protection.

The reason that macrovision was implementented in VCRs was because man consumers (not most) did copy vhs movies when given the option.

I don't want to sound like an audio snob here (I use analog out to my receiver for TrueHD and DTS-HD), but why are we worrying about spdif when HDMI is becoming the new standard for digital audio for movies?

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Because he is using the Maui based MSI Diva motherboard which has a very impressive 5 channel internal amplifier.
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post #58 of 199 Old 02-05-2010, 05:39 PM
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I'm trying to get this to work with a Diamond Xtreme Sound 7.1/24 bit (XS71DDL) pci soundcard (from the drivers, it seems to use a c-media chipset.. haven't looked up the exact model). I'm not an audiophile, and am definitely in way over my head on this; whenever I try to use graphedit with AC3Filter and any of the input (WDM streaming or audio input) and output filters, the decoder log reads:

Input format: PCM16 2/0 (stereo) 44100
User format:
Output format: Unknown - 0

I've tried with windows xp and 7, and would gladly try with any other OS. I'm hoping to be able to get 5.1 sound from my xbox 360 to my computer speakers, but can't even get 2-channel pcm through the toslink spdif connection. Obviously, I'm doing something very basic wrong in all of this. I realize this is a very complex issue and don't expect someone to walk me through everything I have to do to get it working with my card (if it is even possible), but could someone tell me how to get "Despdif" in the decoding chain or get AC3Filter to recognize the output format I choose?

Sorry to bother you experts, I've been trying on my own but have hit a wall. Thanks in advance for any advice..

Edit: haha, ok, I got 2 channel working now, disregard this post for the time being.. unless anyone has general tips for how to get this setup working. The sound card I'm using seems to use the CMI8768 chipset; I got a new driver and now that 2 channel works, I'm playing around trying to get 5 channel etc. to work. Thanks for this great thread btw, I learned a lot in this thread.
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Quote:
Originally Posted by parvulus View Post


Edit: haha, ok, I got 2 channel working now, disregard this post for the time being.. unless anyone has general tips for how to get this setup working. The sound card I'm using seems to use the CMI8768 chipset; I got a new driver and now that 2 channel works, I'm playing around trying to get 5 channel etc. to work. Thanks for this great thread btw, I learned a lot in this thread.

I never got the 5.1 sound to work with my PS3 in Win7. While I was using XP 64bit, AC3Filter would recognize the DD or DTS bitstream coming through spdif. I think someone mentioned that the newer drivers that are used by Vista and 7 disable the cards that could pass the bitstream to AC3Filter from doing it anymore. Now this is my experience with the PS3 and PS2, so it's entirely possible that it is different with Xbox, but I'm pretty sure that's how it works.
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post #60 of 199 Old 02-17-2010, 10:06 PM
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Not sure if this is the right topic but it seems similar enough, i installed this to my computer via usb. I have a toslink/optical cable going from my xbox 360 to this adapter. It sounds like it's only doing 2 channel, how do i get it to go through all the 5.1's hooked up to my pc? I'm on windows 7

It seems like I need to do this..
Quote:
Source outputting a 2 channel PCM stream ---> SPDIF input on your computer ---> Audio signal remixer ---> Audio 5.1 speakers connected to your computer.

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