DV type 1 vs. type 2 (sync error)

[mdavis]

I have been trying some analog captures using my Sony DV camcorder as a pass-though with the firewire connection to my computer. Whenever I capture DV type 2 the resulting avi gradually looses audio sync such that it is about 1-2 secs off after an hour. However, when I capture in type 1 mode the audio stays in sync the whole time. This happens whether I use DVIO or Scenalyzer to capture and in all cases I did not have any dropped frames. Does anyone have any idea why this would happen?

I currently have the panasonic codec installed for type 2 files, but I'm not sure if this influences the capture or not. Is a particular DV codec used during capture, or is the raw data from the camcorder just formatted and saved to disk by the capture program without any usage of the codec?

A related question, does anyone know if the MS DV codec still has the upsampling chroma bug with DirectX8.1? The avisynth documentation refers to it but not to a particular version.

"FixBrokenChromaUpsampling(clip)

I noticed that the MS DV codec upsamples the chroma channels incorrectly, and I added a FixBrokenChromaUpsampling filter to compensate for it. You should put this after DirectShowSource if you're using the MS DV codec, or if you notice off-color lines appearing in interlaced images"

Thanks

[yg1968]

I don't know why this happens but a workaround would be to capture in type 1 and convert to type 2 using the Ulead converter in the tools section. I am not 100% sure but I don't think that a codec gets used upon capturing a type 2 DV file. It only gets used upon editing a type 2 file. A type 2 DV avi file essentially extracts the audio from the DV file and keeps it as a separate audio stream. Because of this, there is more risk of a type 2 file being out of sync than a type 1 DV avi file. However, I have not experienced this out of sync probem with type 2 DV avi files.

[fingernailX]

I have similar issues regarding sync but my experience has been that if I use a wdm based capture program such as IuVCR or Ulead Video Studio 7 even with a type 2 codec my a/v sync issues disappear. I believe dvio is vfw based ( it worked under Win98 even before the Digital Video patch).

[Rich927]

I too tried passthru but I had better luck copying from my VCR deck to my DV camcorder then transferring from camcorder to computer via firewire. The DV time base coding was more stable.