Mpeg-2s Rendered for DVDA

reberclark wrote on 5/26/2008, 10:05 PM

I have searched the board and this seems a perennial topic but there is SO MUCH info that I am hoping for a more concise answer.

I use G-Spot now to read my Mpeg-2 properties from my camera. G-Spot indicates that they are TFF (top or upper field first), unless I am misunderstanding the "t (time)" readout in G-Spot.

My renders to NTSC DVD Widescreen for DVDArchitect are set up for Lower field first in Vegas (8 Pro). Is this a conflict that will degrade (soften) the already lossy render? If so is there any way to improve this? My camera is not the best but I feel I am losing too much in my render for DVDA.

Thanks from near the bottom of the learning curve.

Comments

owlsroost wrote on 5/27/2008, 1:38 AM

It might degrade the quality (depends on how Vegas is fixing the problem).

DVDs can be either field order, so just load the standard 'NTSC DVD Widescreen for DVDArchitect ' render template, change the field order setting to 'upper field first' and save it as a custom template. The standard template is set up as lower-field first because DV video is lower-field first - MPEG can be either field order (or progressive).

If the source MPEGs are 'DVD compliant' then VP8 can smart-render the project to DVD-compliant output, saving a lot of time and maximising quality - see this thread [url=http://www.sonycreativesoftware.com/forums/ShowMessage.asp?ForumID=4&MessageID=580758] for info.

Tony

reberclark wrote on 5/27/2008, 9:04 AM

Thanks Tony. That was a very informative link as well.

What do you recommend for a project consisting of MPEG-2s with varying field orders? (some are Upper first some are Lower) The target is NTSC DV Widescreen for DVDA and it includes many types of files from JPGs to MPEG-2s to AVIs.

I have had good luck except for the MPEG-2s with Upper Field First field order - these are very "soft" on the re-encode for DVDA. I hesitate to re-encode these with Lower Field First then re-add them to the project - fearing even greater loss. I have considered AVI as an intermediary.

All ideas appreciated!

owlsroost wrote on 5/27/2008, 11:44 PM

Difficult - usually I'd choose an output field order that matches the majority of the source material.

You should choose 'best' rendering quality to minimise the image softening of the clips with the 'wrong' field order - it looks like Vegas is convering the field order by interpolating the new fields from the old ones.

In the past, I've occasionally processed files through VirtualDub to flip the field order, using the 'Reverse Field Dominance' plugin from [url=http://neuron2.net/reverse/reverse.html] (this does it by shifting fields rather than interpolation).

VirtualDub is here - [url=http://www.virtualdub.org/] - and the MPEG plugin (so it can open MPEG-2 files) is here - [url=http://fcchandler.home.comcast.net/~fcchandler/].

Note VirtualDub can't output MPEG - you'll have to save the output as an AVI file, but using a lossless codec like Huffyuv will minimise the overall degradation (provided you have the disk space....)

(If you haven't come across it before, VirtualDub is a freeware video processing tool with a huge collection of processing plugins available to do almost anything you can think of.....)

Tony

reberclark wrote on 5/28/2008, 8:48 AM

Hi Tony,

Thanks for your great advice on altering field order with virtual dub and the two plug ins. I can now import MPEG-2s to virtual dub but cannot find the command in virtual dub to run the "reverse field order" plug in. Can you help me? Thanks!

EDIT: Nevermind. Found it! Thanks again!

johnmeyer wrote on 5/28/2008, 9:37 AM

Wow, unless I am missing something, you are wasting your time and potentially unnecessarily hurting your video by doing field reversal in VirtualDub. As was already stated, you can encode to MPEG-2 with either TFF or BFF. Doesn't matter. Either will playback just fine from any DVD player. Just make sure that in the Render As dialog that you use the Custom button to change the field order to match the source. That's all you need to do.

reberclark wrote on 5/28/2008, 9:42 AM

I agree John and thanks for the input.

My problem is that in my project I have MPEG-2s with different field orders - some TFF some BFF. I am attempting to average the inconsistencies for a better render for DVDA from Vegas Pro 8.

I think just rendering to the majority of the files with the same field order is the best solution but I thought I'd experiment with trying to re-order fields in the smaller number of files.

I suspect, after a few tries in V-Dub, that re-ordering fields is way too much effort for the task I want to accomplish. All info appreciated.