MPEG-2 Output Quality Issues

Hemant Kamat

Newbie Joined: Mar 11, 2013 00:30 Messages: 18 Offline

Solved by

Mar 18, 2013 01:50

I'm trying to make a standard HQ DVD from some AVCHD 1920x1080i files.

The video is a recording of a stage performance by a group of children shot from the audience.

The resulting output file shows considerable loss of detail when compared to the original (zoomed out to 1:2.25 - 720x480 in VLC.)
The facial features of the children are barely visible in the output, and the childrens' faces look blurred.

However, if I use the Video Crop tool to zoom in on a couple of the children, the resulting output file is comparable to the original (viewed at 1:1 - 1920x1080 in VLC.) The facial features are almost as detailed as the original.

So, what is going wrong in the first case? Is the MPEG-2 encoder excessively compressing the video? Is there any way to increase the quality of the output video using a custom HQ DVD profile setting?

Thanks for your help.

BarryTheCrab

Senior Contributor Location: USA Joined: Nov 06, 2008 22:18 Messages: 6240 Offline

Mar 18, 2013 07:32

Hemant,
DVD's have much less resolution than your HD files, so the result will never compare favorably.
When you video-crop, and the faces are clearer, are you still in the editing phase? If so, you are still viewing the HD files. Try the crop, then burn the file in SD, I think you'll find a loss of resolution again. HP Envy Phoenix/4thGen i7-4770(4@3.4GHz~turbo>3.9)
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Hemant Kamat

Newbie Joined: Mar 11, 2013 00:30 Messages: 18 Offline

Mar 19, 2013 00:17

Quote: When you video-crop, and the faces are clearer, are you still in the editing phase? If so, you are still viewing the HD files. Try the crop, then burn the file in SD, I think you'll find a loss of resolution again.

Thanks, Barry.

No, I rendered a smaller clip to compare the quality with the original. The MPEG-2 encoder seems to be the culprit - it cannot maintain details on smaller objects. I'm contemplating using the cropping tool to zoom in and pan slowly from side to side.

On a related note, a few clips where I have used transitions (fades, tumbling blocks) are exhibiting a ghosting effect - a shadow of the blocks/last frame from the previous clip gets overlaid on the new scene for a few seconds. This is happening only at a few places in the video - other clips with similar transitions get rendered without any issues. Oh, and it is always the same scenes that have the problem if I render another output file. Any suggestions on fixing this?

Hemant Kamat

Newbie Joined: Mar 11, 2013 00:30 Messages: 18 Offline

Mar 25, 2013 01:05

Quote: On a related note, a few clips where I have used transitions (fades, tumbling blocks) are exhibiting a ghosting effect - a shadow of the blocks/last frame from the previous clip gets overlaid on the new scene for a few seconds. This is happening only at a few places in the video - other clips with similar transitions get rendered without any issues. Oh, and it is always the same scenes that have the problem if I render another output file. Any suggestions on fixing this?

No comments on this issue? I tried disabling hardware rendering, un-checking & deleting the shadow files, disabling the preview during production, to no avail.