Repairing Parts of MPEG2 Video Files

[montgal55]

Hello Everyone:

First, let me say excuse my ignorance if I use the wrong terms not being familiar with video terminology. . . .

In reviewing and editing MPEG2 files before DVD authoring, I notice that in some spots frames (or pixels) sometimes become jumbled (or probably a better word, ¡§discoloration¡¨) occurs. It only last for a few frames (or seconds), then the video comes back to normal (picture perfect).

This does not happen when viewing the same scene(s) in the AVI version. But when converting from AVI to MPEG2, this does occur. Not all of the time, but you have to watch the entire video again just to keep a close eye out.

Is there a utility (if it exists) where I can have MPEG2 video files scanned for frame problems and have them repaired? (I was just wondering in the conversion process if there is something I can do {e.g., option settings in the conversion program.} I am using Mediacoder

Montgal55

[sjj1805]

The term for what you describe is "Blockiness" and is normally caused due to low bit rates or poor source material. When I converted my few hundred VHS tapes top DVD whilst most converted successfully, some suffered the effect you describe despite using the same equipment and settings. Therefore the source material (worn tapes) was at fault. However it can also be caused by attempting to capture with the settings too low.
Sort of like setting a VHS recorder to extended long play rather than standard play.

[montgal55]

sjj1805:

It seems that you were correct when you indicated that the settings were too low in my AVI to MPEG2 conversions.

I was setting my bitrates at 1000kbps. But when I revised the setting to, or a little bit above 6000, my MPEG2 files came out to be perfect.

At first, I thought the 5000-7000kbps was to high because I wanted to make a smaller converted file. But I was told make the file smaller during DVD authoring process instead. It is at that point I can lower the bitrate to fit a file on a single-layer DVD disc.

Montgal55

[skier-hughes]

you don't want to convert a file twice this will lose more quality than doing it once, even if you end up at a bitrate that is the same.
If it needs to be at 1,000 to fit on a single layer dvd, then you need to shorten it or put it on several dvds.
an hour at high quality will fit, an hour and a half will normally be ok, longer than this and you'll have to forgo quality for one dvd.

[montgal55]

skier-hughes:

Thank you so much for your input.

Since getting files onto one DVD discs is my goal, I will have to start utilizing a video editor to make my files shorter to fit. Especially since I create motion menus, import my own background images, and use custom background music, which could make the menu 41-55MB in size. And starting this weekend, I will begin to use background video loops in my menus.

If a file is, say, 1hour and 53minutes long, it will not fit on a single-layer DVD-R disc. So I have to adjust (cut) the bitrate amount almost in half. Or, as I indicated earlier, shorten the file. Cutting the bitrate in MFpro7 scares me because I don't know what the finish product will be (e.g., quality loss, scene loss, A/V sync issues, etc). Especially when I cut it so-o-o low (e.g., from 7000kbps to 3000kbps).

Montgal55