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This is to show the difference between going directly from a high quality DV-AVI to DVD compliant MPEG compared to reencoding from MPEG to MPEG. This is an extreme example considering the bitrates and the source I'm using. The lights are moving moving and flashing so the examples do a good job of illustrating the differences. Also note that I'm using JPG's which themselves are a lossy format so they are not entirely accurate.
My source video is a DV-AVI it's a very high quality source. Lower quality sources may mask the results. I encoded the AVI to both 8000CBR and 3000CBR. I also reencoded the 8000 CBR to 3000CBR. I'm using Ulead MSP using basic templates with the exception of the bit rates.
Here'a a screenshot of the AVI:
The 8000CBR MPEG, notice the edges of the center light produce a little macroblocking. Very little and would be imperceptible when it's playing:
The 3000CBR MPEG encoded from the AVI, Lot's of macroblocking:
The 3000CBR MPEG encoded from the 8000CBR MPEG, a real lot of macroblocking:
As you can see the the mpeg reencoded from the mpeg shows signifgantly more macroblocking compared to the one encoded directly from the AVI. Encoding from the best source always produces a better result, if your just cutting and trimming the ends, adding a few transitions and most of the video doesn't have to be reencoded that just may be the way to do it. It's definitley faster. Personally I'm a perfectionist and prefer to have the highest quality video I can get.
Here's links to the videos (10 seconds) the example frame above is at 7 secs. 2nd frame:
Right Click and select "Save As"
- 4MB 3000CBR from AVI
- 4MB 3000CBR from MPEG
- 36MB AVI
I Did a little more experimenting. I took my AVI source and created a 6000VBR MPEG to be used as a source file. I split the AVI source in half and did a 4 second crossfade, so we have 1 second on either side with no cross fade. I then created a 6000VBR MPEG from the AVI.
I then did the same thing to the MPEG that I'm using as a source file. Here's the results.
The MPEG encoded from the AVI:
The MPEG encoded from the MPEG:
If you focus your attention on the light to the right you can see a slight difference. Is it huge difference? No not really, but with the combination of high quality 3CCD cams coming into the consumer market and TV's becoming larger and larger any quality loss will be noticeable.
Here's some close-ups, notice the right edge of the blue light:
The MPEG encoded from the AVI: ---- The MPEG encoded from the MPEG:
The clips themselves (4MB each):
- MPEG encoded from AVI
- MPEG encoded from MPEG