Difference between Canopus DV converter and Four-CC changer?

[Corrado]

Hi all,

until now, to bring my DV tapes (and recently also my S-VHS tapes) into DVD format, I used the Canopus DV converter before compressing with TMPGEnc and/or before editing the captured AVIs with Virtual Dub.

This was because Virtual Dub didn't open the "dvsd" DV-AVI format created by Studio 9 (my NLE/Capture software) and also because TMPGEnc failed on 30% of the "dvsd" Avi files, while everything works with the AVIs converted into "cdvc" format by the Canopus DV converter.

Thinking that it might just be a decoder problem rather than a real file format problem, I tried changing the Four-CC code from "dvsd" to "cdvc" with the 4-CC code swapper, which takes 1 second while the Canopus converter uses 50% of the movie duration...

Now both TMPGEnc and Virtual Dub work fine.....apparently. Am I doing the right thing, or am I just messing it up?

Thanks for any hint
Corrado

[Logiqx]

Yes, that is fine as there are just 8 bytes that need changing in the file to force use of the Canopus codec (two instances of 'cdvc').

You might also want to try a utility that I wrote for achieving this:

http://www.logiqx.com/Tools/AVI2CDVC/AVI2CDVC.shtml

It may be more convenient than the generic FourCC changer.

Logiqx

[Corrado]

Thanks Logiqx for the hint and for the useful tool. Normally I capture one single AVI file and change it's 4-CC code, but in some cases I work on many short clips and your tool will be useful :)

Meanwhile I used the 4-CC swap method on 12 clips just yesterday, and they all worked in TMPGEnc for the compression, without any problem ;)

PS:

I also noticed another possible advantage, but I'm not sure if it's a real one.... When I converted the AVIs with the Canopus DV converter, they looked on the PC with a slightly higher brightness than the source, and with less contrast. This effect remained also in the final MPEG-2 file.... I can't say anything about the difference on TV screen, of course, because I can't play the original AVI on TV.

If it was a problem of the Canopus DV decoder, I should have found the problem also in the videos I made yesterday, but I didn't notice the same problem...so I guess that it's a problem of the DV converter. Is this possible?

[bb]

No, the DV type-1 / type-2 converters don't modify neither the video nor the audio. They just "repack" the streams, nothing which could change brightness.

Verify your TMPGEnc colour settings in your DVD profile, especially the "Quantize matrix" tab, section "Special setting": there's "Output YUV data as Basic YCbCr not CCIR601".

bb

[Corrado]

Originally posted by bb
Verify your TMPGEnc colour settings in your DVD profile, especially the "Quantize matrix" tab, section "Special setting": there's "Output YUV data as Basic YCbCr not CCIR601".
It was not checked, now I selected it, thanks.

But the problem was not starting on the MPG file, but on the AVI file after converting it with the canopus DV converter. Or, if you prefer, it is in the decoder used after the conversion....which should be the same after using the 4-cc code swapper, though. :confused:

[Logiqx]

All of the DV codecs produce slightly different results when processing the same AVI. They all have their own little tweaks and filters included so it is possible that the brightness may also be affected (although that would suprise me if I am honest).

There is a comparison of the codecs at the top of this forum (one of the sticky threads).

Logiqx

p.s. When using the Canopus codec, be sure to push it through AviSynth and apply the FixChromaUpsampling function.