Codecs for VCD

[rawn]

Hi.
W2K and WXP
ATI 64 DDR VIVO
P4 1.7
ATI Multimedia Center 7.6

I'm capturing videos using the ati multimedia center 7.6, in vcd quality, but the playback is choppy in spots. I watched the movie I captured, and the image and sound breaks up in the same places each time. I captured the same movie a few months back, and when I play it from the CD, it is fine. But when I copy the mpg onto my hard drive, it will also play choppy, but about 10-15 seconds later. I've discussed this problem with a friend, and read several threads on similar problems, and this might be a codecs problem. My question is: what codecs whould I have installed to capture/play vcd quality videos?

Thanks for your time!
Rawn

[chipzoller]

Let me see if everyone is reading this correctly:

You are trying to capture from an analogue source using ATI MMC 7.1 into the preset VCD specs and you get choppy playback?

I have an ATI TV Wonder PCI edition and have used MMC 7.1 but I must say that VirtualDub does a MUCH better job. I would highly suggest you give it a whirl.

Now the second part you ask about VCD codecs? Well VCD really doesn't have a codec because its uncompressed video, and since CODEC stands for COde/DECode, it doesn't function in VCD.

Read some tutorials and specs for VCD, it should mention it all there.





Chip

[smiller667]

Well ... VCD is not exactly uncompressed video ... VCD is mpeg-1, and even windows mediaplayer has filters for playback. SVCD is a different thing, mpeg2 is used and an appropriate filter is required for playback (DVD software players come with such a codec).

[chipzoller]

Yes, thats quite right. I did not mention SVCD which as the previous poster mentioned, is compressed video. VCD is MPEG-1 stream which according to the ISO (International Standards Orginazation) is uncompressed. However, this does not necessarily mean that no filters can be applied as is the requent case in Windows.



Cheers!



Chip

[smiller667]

Mpeg-1 is compressed video. If it was uncompressed, there would be no way you could ever fit 74/80 mins of VCD-resolution video on one CD.

[Marcel]

Or, to let numbers speak,
Frame size of VCD (PAL): 352*288 => 101.376 pixel/frame
in RGB, every pixel needs 24 bit => 304.128 bytes/frame
25 frames per second => 7.603.200 bytes/second
60 seconds per minute => 456.192.000 bytes/minute

a really hard job to get 74 minutes on one CD.
And look at VCDs, around text or when the whole picture is filled with an explosion. You can see the compression.

So VCDs need coding / decoding. The MPEG1 decoder is part of windows since ages, so nobody notices it.

I'd also capture in VirtualDub into an AVI file, using a good quality (and expecting large files) and transform it into an MPEG1 file later.