John, I found the following definition in Wikipedia :

In true transcoding, the bitstream format of one file is changed from one to another without its undergoing another complete decoding and encoding process.

This led me to believe transcoding was different from rendering.

Is this what Vegas is doing? I ask because the AVCHD to ProRes HD "transcoder" available from Panasonic (and written by Mainconcept) is much faster than Vegas rendering Cineform Intermediate from AVCHD. I assumed it was the difference between "true transcoding" and re-rendering. Is it instead, just the difference in efficiency between the Vegas/Cineform and Mainconcept processes?

Jerry

What are your system specs? If you have a Quad Core and at least 2 GB of RAM I would recommend you editing AVCHD directly. Every time you transcode to another codec you will sacrifice some picture quality, even if not drastically so depending on how good the intermediate codec is.

Panasonic offer a standalone transcoder from AVCHD to DVCPRo HD. This latest version 2.1 will also down convert to AVI DV for 1080 (not 720P) format AVCHD.

Here's the link https://eww.pavc.panasonic.co.jp/pro-av/support/desk/e/download.htm#avchd

New Hope Media

Regardless of definitions, you cannot go from one compression format to a different format without re-rendering (i.e., uncompressing and then re-compressing). There WILL be loss, and it WILL take a lot of time.

The problem is that there is not any equivalence as to how a pixel of video is compressed when looking at one compression scheme vs. another. I suppose there might be some exceptions to this rule -- perhaps you could go between MJPEG to DV to HuffYUV without recompressing -- but I doubt it.

You can always tell simply by keeping track of how long it takes. Transcoding should be MUCH faster than rendering.

I looked at the Wikipedia entry, and despite the semantics, they actaully are describing re-encoding. Just look at the first line under heading "drawbacks," and it says

"The key drawback of transcoding in lossy formats is decreased quality."

Well, how is that any different than re-encoding? Answer: it isn't.

Of course you can always go between lossless formats without loss of quality (from HuffYUV to MJPEG with 0% compression, for instance), but I'd hardly call that transcoding. In fact, in reading the Wikipedia entry, I'm not sure that I can find an actual example of going directly from one compression mode to another without first uncomrpessing and then recompressing.

The one thing that might be called transcoding is the sort of thing done by DVD Shrink and Nero Recode (same author, I think). I've linked before to the author's explanation, and as you'll see, even this really isn't transcoding:

[edit] The original post no longer exists, but it is quoted here:

DVD Shrink Explained

John
Transcoding should be MUCH faster than rendering.

When importing AVCHD into Final Cut Pro the process is quite quick and it is transcoded/rendered/whatever to Apple ProRes in faster than real time as part of the import process.

Once in the ProRes format the files sizes are much larger than the original AVCHD but play perfectly well inside FCP.

I've found that on, the same system (via Bootcamp/Windows XP) Vegas doesn't play the native AVCHD files well (on a Mac Pro with 2 x dual 3 GHz ZEONs and 10GB RAM) and rerendering into other formats takes an enormous amount of time.

This has made me move to FCP for editing AVCHD files and, as I'm about to get a new Panasonic HMC-152EN, I guess I'll be there until Vegas improves its AVCHD performance.

New Hope Media

New Hope, I have the Panasonic HMC150 and no Mac, so I'm stuck with Vegas. I am hoping the next release provides some significant relief.

I've looked at the Panasonic transcoder for AVCHD->ProRes HD. It is fast but the resolution is lower - I forget, maybe 920 horizontal. Is that the same on FCP, or does it maintain the full HMC150 resolution?

Jerry

I haven't tried the AVCHD to ProRes HD under Windows so wasn't aware of the resolution issue there.

FCP on the Mac produces 1920x1080, if that is what the original format was recorded on the camera. It will also convert 1440 x 1080 to display at 1920 x1080 if that's the original format.

Yeah, I certainly like Vegas and have been using it for years. Bought the Mac Pro because it was actually cheaper than getting an HP or Dell equivalent. Now I'm slowly migrating my software to Mac though I'd remained editing in Vegas while using Motion etc from Final Cut Studio 2. The AVCHD problems arose when I bought a Panasonic HDC-HS9 as a home movie camera earlier this year and then a client supplied some footage shot on a Sony AVCHD camera for a corporate edit.

Up until now my corporate work has been shot on my trusty Sony PD-150 but I should pick up my new Panasonic HMC-152EN in the next few days so I'm seriously dedicated to AVCHD in the future.

Like you I hope Vegas makes dealing with AVCHD easier, with smoother replay.

My system certainly should be able to cope with the format in Windows and Vegas as smoothly, and quickly, as it does under Mac OSX and FCP. Whether that's editing from native AVCHD (m2ts) files or converting them quickly to another codec without quality loss, preferably as an option on import, isn't really an issue to me.

The issue is speed, quality and handling ease.

http://www.newhope.com.auNew Hope Media[/link]

Thanks to the AVCHD frame boundary freeze issues, I ended up carefully re-rendering all of my AVCHD footage from the HMC150 to the Vegas-bundled Cineform codec. This involved leaving off the last 15 or so frames of each clip.

Once in Cineform, things worked well, except for some red-frames & a few other odd visual artifacts. Normally a save + restart (of Vegas) fixed these, at least temporarily.

I was able to do the work; but AVCHD is a long shot from "easy" to use in Vegas 8 Pro.

Has anybody done extensive testing of Cineform NEO HDV with the Panasonic (or other AVCHD) cameras? Does Neo eliminate the red-frame and other artifact issues?
--
Mike

"AVCHD frame boundary freeze issues" + "red-frame and other artifact issues"

I haven't experienced any of these problems in FCP.

Are they a common problem in Vegas and/or Windows based NLEs?

New Hope Media

Stephen , I discussed this with Mike last night. What has worked for me (your mileage may vary) is this: I stack all my AVCHD clips end to end on the timeline, place a region around the whole set, and batch render to Cineform using the included batch render script, selecting the render region option. I've rendered several hundred AVCHD clips this way without issue. When I tried rendering the normal way I DID get some freezeups as Vegas tried to render near the clip end boundary. Others have reported this as well.

The red frame issue is only in the timeline view - afaik it doesn't show up in the rendered footage.

Jerry

>"AVCHD frame boundary freeze issues" + "red-frame and other artifact issues"