-
DSE – not trying to start a controversy but….
Spot,
I am still trying to figuree out if Vegas captures type 1 or 2 avi files. I have used you as one of my expert sources and you have stated several times that V captures type 2. Howevber when I try to pass that wisdom am I get slammed (maybe thats my problem, I should not try to pass it on :>).
Here is a missive I received: (I am just trying to educate myself)I am correct… I have been capturing DV with Vegas since before the
type 2 format actually existed. When IEEE1394 hardware support was brand
new, Microsoft included their original DV CODEC, which was naturally
coded for DirectShow, since that was their new, official multimedia
subsystem back around the Windows 98SE timeframe. Before that, the
DV capture tools on Windows were proprietary. This was the only DV
support around, and supported on any “modern” NLE, such as Vegas Video 2.0
(I actually started using Vegas Pro back in the day, but that’s back
when it was an audio-only NLE), ULead Media Studio Pro, and most of the
consumer products. In fact, Vegas was (and is) the most complete
implementation of a DirectShow-based NLE — even the FX and other pieces
are implemented as DirectShow filters (sadly, not something that’s taken
root in the industry as well as the CODEC add-ins for audio and video).But, the big old apps Adobe Premiere and a few others didn’t support
DirectShow at the time DV started to become an important format to
include… they only supported Video for Windows, the multimedia
subsystem that originated in the Windows 3.1 days. You couldn’t even
directly support a DV stream under Video for Windows, because VfW has
certain A/V interlacing constraints that are different than those of DV.
But eventually, folks like Adobe came up with a hack — by duplicating
the audio interleave in a DV stream as a VfW stream, and simply ignoring
the embedeed audio in the original DV stream, they could convert a
normal DV file (which is essentially just the raw DV stream from the
camera along with some AVI structure) to something that would work under
Video for Windows. That because the DV type 2 file.What adds to the confusion is that the AVI file format wasn’t replaced
to deal with video under the DirectShow subsystem, just revved. So DV
Type 1 files are stored as an AVI 2.0 format file, and DV Type 2 files
are stored as AVI 1.x format files.I’ll admit I’ve been in HDV land for two years now, but Vegas has
supported Type 1 files, and captured Type 1 files, since it started
supporting video… long before Type 2 had been invented. There was a
time it didn’t support Type 2 at all… they’re to be avoided if
possible, it’s common to run into audio sync problems with Type 1 files,
they waste disc space, etc. If Vegas supports Type 2 files now, great,
but you don’t want them or need them, unless you’re interoperating with
older software, or perhaps free stuff like VirtualDub, which only
support Type 2 files.—
Dave Haynie | da**@***********ia.com -
1 Reply
-
I believe there is something missing in your understanding of what differs between type-1 and type-2 DV.
Type 2 is type 1 except that the audio is in there twice. The second copy is extracted from the mux into an AVI level audio stream.
DV type 1 AVI
AVI wrapper[DV video+audio]
DV type 2 AVI
AVI wrapper[DV video+audio|dupe audio-stream]
Sync issues should not occur with type-1 as it is a blind bit copy at ingest. Rendering could make it go wrong, and both directions are vulnerable with type-2.
So Vegas support for DV, and what it captures has moved on to type-2 because this is the most acceptable format for other applications that might share the same capture contents or subsequent file renders. Type-1 is more pure but at least for Windows apps, it is the less adopted form.
Coders that wrestle with the microsoft AVI writers and the non-Sony codecs themselves have historically tripped up on both device access and timing issues with the microsoft libraries. So type-1 has been turned to because it is less dependent on getting these aspects bang-on right. I believe XP sorted out many of the firewire issues with DV device control and access. Think of that as a patch update that just needed paying for. 😉
GSpot may help you identify the properties of what you’ve captured going back to VegasPro.
Reply to this Discussion! Login or Sign Up