Capturing sound from Cave (and other) PCBs

Post by **Icarus** » Tue Oct 09, 2007 2:43 am

Just got a SCART to VGA scaler unit for capturing, which works great. However, there's now a problem with sound capture...

Is there anyway to capture sound from the PCB without distortion? The PCBs sound fine as normal, but when they are recorded to a file, there's an unusual distortion that shaves or flattens one side of the soundfile, like so:

The audio sounds fine uncompressed, but as soon as it's compressed with the usual MP3 settings, the distortion becomes really noticeable. Like the game is being played underwater. -_-;;

Here's a clip of the game with the distortion in the sound. Encoded with the usual XVID and MP3 settings (44100, Stereo, 96kbps).

Help...?

Post by **undamned** » Tue Oct 09, 2007 3:48 am

Well if the file sounds fine uncompressed, doesn't that mean you just need to change settings or use a different compressor?
-ud

Post by **Icarus** » Tue Oct 09, 2007 3:50 am

undamned wrote:Well if the file sounds fine uncompressed, doesn't that mean you just need to change settings...

Tried that. Sounds wobbly no matter what I'm using.

undamned wrote:...or use a different compressor?

Anything to recommend? Preferably something that won't bloat the filesize and will retain as much quality as possible?

Gwyrgyn Blood · Post by **Gwyrgyn Blood** » Tue Oct 09, 2007 3:59 am

I had this problem once before randomly and I'm trying to remember exactly where it came from. Check your source file's audio frequency and see if it isn't maybe slightly off what is correct (like being 11024kHz instead of 11025).

For compressors, I just use the LAME MP3 codec which works fine for me. Failing that, maybe try OGG?

Post by **Icarus** » Tue Oct 09, 2007 4:18 am

Gwyrgyn Blood wrote:I had this problem once before randomly and I'm trying to remember exactly where it came from. Check your source file's audio frequency and see if it isn't maybe slightly off what is correct (like being 11024kHz instead of 11025).

Checked, everything seems to be in order (44100, 16bit, Stereo).

Gwyrgyn Blood wrote:For compressors, I just use the LAME MP3 codec which works fine for me. Failing that, maybe try OGG?

Just installed LameACM 3.97 and tried it out, and it still does the underwater thing, so that's out of the window. I have OGG Vorbis, but it does not seem to play back any audio after encode, although I might have an older version.

Point me in the direction of a newer version of OGG?
Or any other alternatives/suggestions?

Thanks for the help so far.

zakk · Post by **zakk** » Tue Oct 09, 2007 4:42 am

Throw one of the sides of the uncompressed audio away and see if it still sounds weird after you encode it.

And then just do that permanently, since the sound is mono anyways...

Post by **system11** » Tue Oct 09, 2007 7:37 am

You know that the sound coming off Cave PCBs is already horribly compressed and of shitty quality, right? You just can't tell as much on a cab, like you can in a quiet environment with just the music.

Post by **Icarus** » Tue Oct 09, 2007 9:25 am

zakk wrote:Throw one of the sides of the uncompressed audio away and see if it still sounds weird after you encode it.

And then just do that permanently, since the sound is mono anyways...

Tried that, still muffled. Even tried capturing sound in mono, and the same thing occurs.
I'm assuming it's something to do with my capture setup. Is there no other way of getting sound off a PCB to the PC? Or repairing the distortion with a filter of some sort?

EDIT: Never mind, fixed it. Seems it's a problem with both the capture setup and the audio compression codecs used for video. Solution is to use a pure audio compression program instead.
Seperate video stream only with XVID and audio stream as an uncompressed WAV, using VirtualDub. Encode WAV to VBR MP3 (192kbps base rate, 320kbps max) using RazorLame, then merge both XVID and MP3 together using Nandub. Sorted.

Post by **undamned** » Tue Oct 09, 2007 4:29 pm

So how is the quality of the overall video after encoding, vs a standard video capture card on your pc (composite / s-video)?
-ud

Post by **Icarus** » Wed Oct 10, 2007 3:23 am

undamned wrote:So how is the quality of the overall video after encoding, vs a standard video capture card on your pc (composite / s-video)?

Despte being fed through several scalers, the quality seems fine. Part of the right screen edge is cut off, but I can live with that. Using my usual XVID settings for decent quality with a relatively low (for 60fps) filesize.

http://bigcore.rsdio.com/icarus/pinkswe ... aptest.avi

A completely roundabout way of capturing and encoding, but I can now record footage from any PCB.
Now to find a Muchi Muchi Pork PCB for the collection. ^_-