Imported DVD-VIDEO displays incorrect bitrate

[THE-KEK]

Hi all,

Basically, I want to use my JVC-M10S dvd recorder to do the bulk of my capturing these days, as I beleive the quality is better than my capture card, a Leadtek 2000XP Expert
I have a PVR from my cable provider that is my source for these recrodings.

I set the JVC to capture at 1:35 FR mode, which gets as close to 6000 kbps, which is what I want as that bitrate, as that is what I have been using for these specific projects when using the leadtek. This is a TV show I record ever week, and have been capturing at 6000 via the Leadtek, and want the keep the projects all the same.

The problem is, when I use VOB2MPG to get the file to my PC, I want to edit the commercials out, before authoring, and I've tried with both ULEAD media studio 7, and ULEAD videostudio 10, but both want to re-encode the file? and I can't work out how to stop it, as the files are DVD compliant, hence being produced by a DVD RECORDER?
When I check the file using G-Spot, it tells me that the file has a 384 kbps audio bitrate, and a 9000 kbps video rate. Thats impossible. 1h and 35mins of footage using a 9000 kbps bitrate on a single layer disc is not possible. The maths will say so.
Why is this all happening? I know the file has a bitrate between 6000 and 6150, so why do these programs report a 9000 kbps bitrate?

To make matters more complicating, if I capture a complete VHS tape, with a length of 3hrs using the JVC, and I VOB2MPG than on my PC, without any editing, I'm able to author that file using ULEAD Workshop 2, without any an re-encoding which would take place if I was editing, but if I were to edit it, it would want to re-encode the resulting file? WHY?

I do set the project settings correctly, as I know a compliant source file does not need to be re-encoded, just renderred, and have been using those programs happily capturing with the leadtek, for the last 3 years, so I'm very competent with them.

I know something is wrong, cause if I were to capture at 6000 via the leadtek, it will report the correct bitrate on the PC, and any editing with not result in re-encoding, it will just render the file which doesn't take long at all as opposed to re-encoding which takes forever.

I would apprecite any help with this matter, as it's driving me nuts.

[guns1inger]

Many programs read the bitrate only from the header information. This can be arbitrarily set to anything, and so cannot be used as a guide. Try Bitrate Viewer - it has been known to be wrong from time to time, but usually it is pretty close. What can you do about it - probably nothing as this information is written by the encoder. You can alter it manually with DVD patcher.

Depending on how you edit, and where you edit, encoding may be required. Mpeg2 uses temporal compression. Put very, very, very simply, the stream is broken down into segments called a Group Of Pictures (GOP). The first frame contains pretty much the entire image. Each subsequent frame holds only the differences between it and the frame before it in that GOP. These frames are then internal further compressed. On playback, the frames are reassembled using the information in the current frame, plus the surrounding frames (I did say it was a very simple explanation - temporal compression can in fact use information from frames before and after the current frame).

What does this mean ? Every GOP must start with an I-frame (the frame with all the info). If you try to put an edit between I-frames, some re-encodng must be done to fix the GOPs affected. Smart renderes will only re-encode the GOPs that need to be done.

If you make any other types of changes - colour adjustments, cross fades, overlaying text etc. then you are effectively creating new video, and all the effected footage must be re-encoded.

Some editors aren't that smart, and will re-encode the entire clip if you change any of it. This is one of the reasons why capturing to mpeg-2 is not a good idea. It was designed as an efficient playback codec, and does not have the nicities of something like DV, which was designed specifically for editing.