YAAP (Yet Another AC3 Plugin) Idea

calinb · Jan 7, 2004, 02:32 AM

I'm trying to build the ultimate HTPC PVR. With KX, I've been able to capture AC3 from my Satellite toslink. Unfortunately, the AC3 stream is padded with extra data that must be removed (fixed) with besplit.exe (http://dspguru.doom9.org/) before the video can be viewed (which requires demuxing and remuxing the video/audio).

It would be wonderful if such a feature could be built into either a Windows ACM or a KX plugin. Then the AC3 stream could be fixed realtime during A/V capture. In fact, such a thing would enable the possibility of "live video pause" like Tivo, ReplayTV and a bunch of PC-based PVRs, but with AC3.

This AC3-capable PVR would be unique--no other PVR has this feature. And it would be powered by KX!

I discussed this idea with besplit developer, DSPguru. He said that besplit is currently closed-source but also, I don't need the whole BeSplit engine; this source-code would probably suffice :

http://home.comcast.net/~calinb/ac3fix.rar

As it stands now, ac3fix doesn't work like besplit because it doesn't decimate the padding so it doesn't make my AC3 recording playable.

Could this sort of thing be implemented in KX? Eugene, what do you think about the options? (I told you my idea wasn't use-level code

)

-Cal

**Eugene Gavrilov** · Jan 8, 2004, 12:25 AM

you won't believe, but ac-3 decoding (spdif-in decoding) is performed in -user-level- by kX Mixer (in 'Direct SPDIF recording' mode)

/E

**dj_stick** · Jan 8, 2004, 07:18 AM

so that doesnt work on 10k1 cards?

calinb · Jan 8, 2004, 06:27 PM

Quote:

Originally posted by Eugene Gavrilov
you won't believe, but ac-3 decoding (spdif-in decoding) is performed in -user-level- by kX Mixer (in 'Direct SPDIF recording' mode)/E

Cool! So I just need to learn how to tweak kX mixer to strip some bytes

**Eugene Gavrilov** · Jan 8, 2004, 10:57 PM

>> so that doesnt work on 10k1 cards

exactly. and this cannot be fixed

>> So I just need to learn how to tweak kX mixer to strip some bytes

well, a better idea is to write a 3-rd party application, that would open 'Wave 0/1', set 'Direct SPDIF Recording' via kX API and would do all the audio processing you wish

/E

**dj_stick** · Jan 9, 2004, 01:36 AM

is there a way to decode AC-3 on a 10k1 card?

kokoon · Jan 9, 2004, 08:20 PM

i believe its not.

Jan 7, 2004, 02:32 AM	#1
calinb DriverHeaven Junior Member Join Date: Jul 2003 Location: Portland, OR USA Posts: 74 Rep Power: 0	YAAP (Yet Another AC3 Plugin) Idea I'm trying to build the ultimate HTPC PVR. With KX, I've been able to capture AC3 from my Satellite toslink. Unfortunately, the AC3 stream is padded with extra data that must be removed (fixed) with besplit.exe (http://dspguru.doom9.org/) before the video can be viewed (which requires demuxing and remuxing the video/audio). It would be wonderful if such a feature could be built into either a Windows ACM or a KX plugin. Then the AC3 stream could be fixed realtime during A/V capture. In fact, such a thing would enable the possibility of "live video pause" like Tivo, ReplayTV and a bunch of PC-based PVRs, but with AC3. This AC3-capable PVR would be unique--no other PVR has this feature. And it would be powered by KX! I discussed this idea with besplit developer, DSPguru. He said that besplit is currently closed-source but also, I don't need the whole BeSplit engine; this source-code would probably suffice : http://home.comcast.net/~calinb/ac3fix.rar As it stands now, ac3fix doesn't work like besplit because it doesn't decimate the padding so it doesn't make my AC3 recording playable. Could this sort of thing be implemented in KX? Eugene, what do you think about the options? (I told you my idea wasn't use-level code) -Cal Last edited by calinb; Jan 7, 2004 at 02:49 AM.

Jan 9, 2004, 08:20 PM	#7
kokoon DriverHeaven Addict Join Date: Feb 2003 Location: slovenia Posts: 269 Rep Power: 0	i believe its not. __________________ [kokoon]

Jan 8, 2004, 12:25 AM	#2
Eugene Gavrilov kX Project Lead Programmer and Coordinator Join Date: Dec 2002 Posts: 3,119 Rep Power: 75	you won't believe, but ac-3 decoding (spdif-in decoding) is performed in -user-level- by kX Mixer (in 'Direct SPDIF recording' mode) /E

Jan 8, 2004, 10:57 PM	#5
Eugene Gavrilov kX Project Lead Programmer and Coordinator Join Date: Dec 2002 Posts: 3,119 Rep Power: 75	>> so that doesnt work on 10k1 cards exactly. and this cannot be fixed >> So I just need to learn how to tweak kX mixer to strip some bytes well, a better idea is to write a 3-rd party application, that would open 'Wave 0/1', set 'Direct SPDIF Recording' via kX API and would do all the audio processing you wish /E