HELP! Trying to capture s-video and digital audio and sync them.

[laureynsr]

Hi All,

I have a Vista Ultimate 64bit PC with a Hauppauge PVR-150MCE, SoundBlaster Audiology 2 ZS and want to transfer my 150+ Laserdisc collection to the Media Center or to DVD. My problem is I want to capture the digital bit stream from my laserdiscs rather that analog audio. My Audiology has both TOS and Coax digital input and the audio is playing through but when I record there is a delay on the video to the audio when I use the WinTV software. Does anyone know of how I can delay the audio to sync it? Is there any cheap software that supports time coding the audio and video streams?

Thanks

[Nelson37]

Describe the audio capture methods and file types, also conversion methods. Are you just capturing PCM audio?

Is the delay constant, or gradually increasing? Approximately what delay value over a one-hour period, either measured or rough estimate?

I cap various sources, though not Laserdisk, S-video plus digital AC-3. Audio delay is minimal and gradually increasing, by about 1 second per hour. The audio is actually early, more correctly the video is delayed.

Possibly unrelated to your issue but does sound very similar.

I know of no easy way to fix this, I use visual waveform matching to a properly synched MP2 analog audio, with a time stretch and re-encode to AC-3.

[olyteddy]

Are both streams the same length? That is is the delay constant? If so, you should be able to demux the Hauppauge stream, and remux the video with the digital audio stream.

[jgreiner_lansing]

I'm trying to do the same thing here (archive my old Laserdisc's to DVD) so will be closely following this thread... currently I am using Pinnacle Studio 12 to capture with, and that program allows splitting audio and video capture sources so I can select my Haupage tuner card for the video, and my on-board sound card for the audio... since my LD only has optical out and my on-board sound only has s/pdif coaxial in I have just ordered (8 Nov 08) a toslink to coaxial convertor to try... once I've had a chance to try will post the results... I have 2 concerns about this setup: 1) bitrate was different (44.1) for the LD AC3 audio than it is for DVD so not sure how well this will convert (if at all) and 2) not sure if my soundcard & Pinnacle will downsample my digital 5.1 input to 2 channels in the process

[Nelson37]

If the output is true AC-3, then downsample is not a problem. What you are capturing is a file, as oppossed to an audio file. It has to be stitched back together using Besplit or VLC before it becomes a standard audio file.

[jgreiner_lansing]

Thanks for the input... FWIW yesterday (11/13/08) I attempted my first capture from the LD ... Capturing software used was Pinnacle Studio 11 with output rendered to DVD w/Dolby Digital 5.1 encoding... Video was captured with a Hauppage HVR-1800 tuner card, audio stream was captured by on-motherboard Realtek HD Audio from a coaxial spdif input... the Pioneer LD player outputs digital optical for the sound, which is converted with an outboard toslink to coaxial convertor... (my pc running Vista x64 with Intel Core Quad 2.66 and 6Gb of memory)... Here's what I'm seeing so far:

1) My onboard sound hardware (Realtek) is seeing the spdif signal, but is not identifying it as an AC3 signal... It is seeing it as a valid PCM 44.1 signal however... I captured this in Studio using AVI with PCM audio... after rendering DVD w/DD 5.1 audio the playback is only giving me 2.0 channel stereo (no surround)... not sure if it is the Realtek that downmixed to 2.0 stereo or the Studio software... I'm going to try VirtualVCR this weekend to see if I can get a raw PCM audio capture into the file.... If the problem is in how the Realtek renders spdif input I may need to go to an outboard processor and capture the 5.1 channels discretely, or switch to a soundcard which allows raw PCM to be output to the file with no downmix

2) Like the originator of this post, I'm seeing around a 200 - 300 msecond syncing problem with the audio... this starts at the beginning of the video & is constant through the end... I attribute this to using seperate audio & video processor cards with different process timing delays... per reading the documentation on VirtualVCR it appears that It is able to + or - timeshift the audio signal so it s/b able to delay the audio enough to re-sync...

Thoughts from the group or any input based on the hardware/software limitations I'm using appreciated.

[jgreiner_lansing]

Update... the audio I was trying to capture was in fact 2 channel PCM off of my LaserDisc (Dolby ProLogic and not true AC3)... checking my extensive LaserDisc collection I only found 1 disc which had true AC3 encoding...

Using VirtualVCR I was able to correct for the video/audio sync delay and obtain a good capture using onboard SPDIF to capture the PCM bitstream, and the seperate Hauppage tuner for the video digitization... additional benefits of going the VirtualVCR route is that I was able to utilize my Pinnacle de-interlace filter (installed by Studio) to obtain a higher quality progressive capture.

Is there any filter which will transcode the matrix ProLogic surround to DD5.1 AC3? I would like to re-encode to AC3 if possible to preserve disc space...

[tonyaldr]

On a related topic, I was wondering if it was better to capture the content into a PC from my Pioneer Laserdisc player or just hook it up to my Panasonic DVD-RAM recorder. Anybody have any opinions one way or another? Thanx and have a Merry and a Happy!