TOSLink or S/PDIF Capture

[Perro Grande]

A few updates:

1) This process works with 2CH AC3 streams, too.

2) Cool Edit works just fine, too. I just captured as a 16bit, 48K WAV, Stereo, saved the file, ran BeSplit, and everything worked.

3) GoldWave and my sound card do not seem to get on. The first time I ran the capture, it captured, saved, and everything looked ok, but BeSplit produced a 0-duration ac3 file. The second time I tried to capture, it looked like it was working, but GoldWave didn't actually capture anything...


From what I can tell, the biggest changes in this whole process were:

1) updated drivers for the M-Audio card
2) setting SCMS to original instead of the "No SCMS" setting (I have not tested to see if this really makes a difference or not).

I really think the driver update is the most likely to have been the fix...

[caduceus]

Perro Grande,

Congrats...now muxing with video will be the next challenge!

1) This process works with 2CH AC3 streams, too.

Yep, should be the same...just digital data.

Dunno if the SCMS settings apply to recording or just passthrough to digital out. I've always set my mixer to interpret digital as "non-audio" though.

Keep us posted if you find out any other useful tidbits.

=caduceus=

[rennervision]

I wanted to resurrect this very handy thread as it details something I'm setting out to do with my AC-3 laserdiscs and a laptop. However, since nearly two years have passed, I realize I probably won't be able to get the original poster's input on this.

The OP mentioned he was using a firewire connection with an M-Audio Audiophile. Would anyone know if this is the one he used? It is the M-Audio Firewire Audiophile:

http://www.m-audio.com/products/en_us/FirewireAudiophile-main.html

I'm unsure for a few reasons. First, M-Audio has told me by e-mail that their products cannot capture AC-3. I realize this could simply mean they are unaware of the "BeSplit trick" outlined in this thread. However, I am also aware that just because a sound card is bit accurate, that does not necessarily mean it can capture AC-3.

In fact, even the OP could not get this to work until he downloaded M-Audio's December 26th 2003 drivers. Those drivers now appear to be long gone, and newer ones have taken their place. So is this still possible with M-Audio?

If anyone has any other suggestions on a firewire product I can use for bit accurate capture of AC-3 on a laptop, I would greatly appreciate it. I would hate to spend big bucks on a bit accurate card that doesn't work.

[bobcat56458]

I’m also trying to capture a DD5.1 digital stream from a DVD player’s coaxial SPDIF output. I can capture the DD5.1 audio using the Audition audio software, with my Audigy 1 Platinum EX soundcard that I’ve installed the kX project drivers that give me bit-for-bit SPDIF capturing capability. I then save the audio as a 16 bit 48kHz stereo file using the “PCM Raw Data” compression with “16-bit Motorola PCM” set in the compression options of Audition. I’m able to then load this saved ***.pcm file into AC3Fix and save it as a ***.ac3 file that I have to rename to a ***.wav file, this fixes the audio. I then run this file through BeSweetGUI and it produces a DD5.1 ac3 file that plays fine. Now I want to take this to the next level of being able to capture both the video, and DD5.1 audio at the same time. I’ve followed caduceus’s instructions for using VirtualDub to do this capturing, but when I run BeSplit on the 16 bit 48kHz PCM wave file it only encodes a 4 second AC3 DD5.1 file (the test file is 1 minute long). I think it would work if I had the option in VirtualDub to save the audio as PCM Raw Data” compressed with “16-bit Motorola PCM” set in the compression options, all there is for an option is saving the audio as 16 bit 48kHz PCM in an AVI container. My ultimate goal is to capture the DD5.1 audio along with the video from my Directv Tivo, as some shows have DD5.1 audio like HBO. Is anyone having any luck capturing both the DD5.1 audio along with the video at the same time, then fixing the audio and encoding it to DD5.1? Rennervision, you should check out the kX project forums and see if the Creative Labs Audigy slot DD5.1 soundcard for laptops would work for you, you would also need the kX free 3ed party Audigy drivers. There would be no need for Firewire in this type of setup.

[rennervision]

Thanks, bobcat56458. Actually, I'm experiencing deja vu because you posted right after me in another forum dealing with this very subject.

I would love to try the kx driver suggestion. Unfortunately, their website indicates the drivers are not compatible with the Audigy 2 ZS Notebook:

http://kxproject.lugosoft.com/faq.php?language=en#Q15

...and judging from their forum, I'm not hopeful that day will come anytime soon:

http://www.driverheaven.net/showthread.php?t=61929&highlight=notebook

But if you were able to capture the video and audio at the same time, that would be awesome. (And, if possible, I might just have to invest in a new desktop!)

[bobcat56458]

I did find a capture program that works at capturing both the DD5.1 SPDIF digital audio and video at the same time. NeroVision Express, capture to the hard drive option, captures the digital audio stream that can be fixed using the method I stated in my last post. You select for the video compressor: No compression (or default), and for Audio compressor: No compression (or default). The problem I’m having with it is that my P4 1.8Ghz computer with 512MB of ram is not fast enough, and it drops frames when doing a capture at 720x480 output resolution. I did not have this problem with dropped frames with VirtualDub but the uncompressed PCM audio could not be fixed correctly. The problem with VirtualDub I think is that while you are doing a capture on the right side under Audio Then where it shows Resample you can see that that it is resampling the audio by a very small amount, probably just enough to make the digital SPDIF audio not the pure stream you need.

[rennervision]

Very interesting. I wonder what would be the best minimum specs (RAM and CPU) for NeroVision Express to work in this capacity?

[bobcat56458]

Good news! I've found a setting in Virtualdub that disables the re-sampling. Go to Capture on the top menu bar, then select Timing in the drop down window. In the window that opens put a check by "Do not resync between audio and video streams". I did a one minute capture test, then imported the audio into Audition and saved it as a PCM Raw Data with the options set to 16-bit Motorola PCM. Then fixed the audio with ac3fix GUI, and changed the resulting file extension to ***.wav, and then made a MPEG2 from the AC3 file created with BeSweet, and the ***.m2v video file I made with TMPGEnc Plus. I then Multiplexed the DD5.1 AC3 audio with the MPEG2 video, and the resulting video file played back correctly on the computer with DD5.1 sound. I'll have to do a longer test to see if I have any audio/video sync problems, and also author a DVD with the MPEG2 file to see if it works with a stand alone DVD player, but it's looking good at this point!

[bobcat56458]

Reading previous posts in this thread I’ve seen there is an easier freeware method of fixing the DD5.1 digital wave you can create using VirtualDub’s Save WAV function. If you are command line challenged (like me) use the following method. After you save the wave file with VirtualDub use a BeSplit command line in Windows, Accessories > Command Prompt. Make sure the 5.1 digital audio file you created with VirtualDub is located in the folder showing in the command prompt window, and the program file "BeSplit.exe" is located there also. Then enter in this BeSplit command line:

BeSplit.exe -core( -input vdub.wav -prefix H:\outputwave -fix -logfile BeSplit.txt -type ddwav )

The “vdub.wav” would be your 5.1 digital wave file, and the “H:\outputwave” would be where you want the DD5.1 ***.ac3 file to be located on your hard drive, then press enter on your keyboard, and when it’s done you will have a DD5.1 ***.ac3 file that is ready to be multiplexed with the video file.

[rennervision]

Thanks for sharing! I'm going to try this - as soon as I find the right sound card.

[bobcat56458]

An now some bad news, I found out that a DirecTV Tivo's optical SPDIF digital output is SPDIF\PCM not The SPDIF\RAW that I would need to record DD5.1 audio from it, I'm bumed out!

[tyee]

Will this method work with DTS input on the SPDIF?

Is the M-Audio Audiophile2496, still the card to get as of Oct 2005?

I was wondering whether the M-Audio "Transit" would work too?

[Nelson37]

Have no clue about DTS, it was not mentioned in the original info I saw. Would think different tools would be needed. Should certainly be possible, the basic mechanics are the same. What comes over that cable is more like a file than analog sound, it just needs to be "fixed".

The audiophile 2496 was specifically mentioned by more than one poster as being capable of the AC-3 capture, haven't seen the other model mentioned. Only 3 cards in total were discussed, one needing hacked drivers.

[tha_specializt]

Hi im new here , i followed your tips about grabbing DD via S/PDIF - my settings are :

48kHz
16 Bit
Stereo

cmd-line BeSplit.exe -core( -input xxx.wav -prefix yyy -fix -logfile BeSplit.txt -type ddwav )

which resulted in the files

http://teamdragonball.de/Untitled.wav
and
http://teamdragonball.de/yyy01.ac3

As you can see - the ac3-file appears to have SOME sort of audio in it but it is distorted beyond recognition ... is anyone able to help me or suggest steps towards the solution?
Btw : the source is Dolby digital via Toslink from a receiver, my soundard is an Terratec Aureon 5.1

[Nelson37]

That is not a valid DD-WAV file. The captured file should be done at 24-bit.

The file should sound like rapidly pulsing static. Turn your volume WAY down before playing.

This is a very old thread, there is more recent info available. Search on AC-3 or SPDIF capture.