Anime backed up with DVDRB.

[3ncrypted]

I was using VirtualDubMod to go thru and compare frames from the original and the end result from DVDRB.(to compare quality) In doing this I noticed that certain scenes where there is a lot of fast movement, had frames that look like the below pic. But I noticed that these frames weren't in the same places in the backup from DVDRB. The new backup DOES HAVE these type frames, but they are in places where the original doesn't have them. So basically the backup has these types of frames in different areas than the original. Is that normal? Out of curiosity, I ran one of the movies thru DVD Shrink, and the end result had these "blurred" frames in the same spot as the original. As far as I can tell this doesn't make a difference when viewing the movie, but I wanted to check to see if this is normal.

Here is a pic of one of the frames:
http://img221.echo.cx/img221/1436/animeframe7ff.jpg
DVDRB/CCE Settings:
VBR Passes= 3
VBR Bias= 25
Quality Prec= 16

[3ncrypted]

I was just comparing another backup, and when I put the frame number in that I was wanting to goto (in VirtualDub), I discovered the DVDRB backup's frame is not in the same spot in the movie as that same frame in the original. I compared the same movie backed up with DVDShrink, DVDRB, & the original, and when I went to a specific frame number.. it would pull up a different spot in the movie for all 3. Could anyone tell me why this is happening or what I'm possibly doing wrong?

BTW, don't know if it matters, but I'm opening a 0.99gb vts file in VirtualDubMod when comparing.

[Fishman0919]

Comparing frames to judge the quality of video is like comparing the taste of Ice Cream by looking at it... is just plain silly. The only real way of judging the quality of video is to watch it. One frame can't, can't, can't tell you how good the next frame is in relation to the one you are looking at... if you want to compare frame then JPEG might work well but not MPEG2.


This might help explain with "blurred" frames

http://www.animemusicvideos.org/guides/avtech/video2.htm

[3ncrypted]

:) Fishman, I like your analogy, and IMHO you're right. I'd just seen posts where people had captured frames for comparing, so I was trying out VirtualDubMod to do the same. Couldn't tell much by comparing the frames, but the DVDRB&CCE backup looked much better when viewed.(big surprise) However, I stumbled across these other issues/questions in the process, and I'm just trying to understand what's going on.

EDIT: I will check out the link you posted. Thanks

[3ncrypted]

..... This might help explain with "blurred" frames

http://www.animemusicvideos.org/gui...tech/video2.htm

I went to that url and did some reading. Thanks for posting that. But is the reason that the frames are the same with Shrink & original, because the output from Shrink is transcoded? And the reason the DVDRB version has these types of frames in different areas than the Shrink version & Original version is because the end result from DVDRB was re-encoded?

[pg55555]

I really do not know shit about digital video (I can understand the old film sistem), but my understanding is the following:

You have I, B and P frames. Depending on the system Pal / NTSC you can have beetwen 24 and 30 frames per second (fps), which is similar to the film, in which each frame is a picture.

In digital video the code for the I frames have all the information, ie they are a complete picture, while the B and P frames contain only the information for the differences with the I frame. So, if we look at a slow motion and then at a hight motion part, in the slow motion part, the B and P frames will contain very few information (ie bitrate) as the diference to the I frame are few. But in a high motion part, while the B and P frames will need to contain more information, as the images they represent will be more different from the I frame. So, while the bitrate for the I frame is the same in both cases, you have less information (ie bitrate) in the B and P frmes of a slow motion part than in the B and P frames of a high motion part

- When you process your source through a transcoder (as Shrink), it does keep the same I, B and P frames, just reduce the amount of bitrate of each of them (usually more in the b and P frames). And a frame as you showed will be very similar to the source

- But when you use an encoder as CCE, the encoder takes the input and generates a new set of I, B and P frames, according to its parameters (bitrate, matrixes, etc). and is very probable an individual frame is more different from the source than in a transcoder, but the scene be better.

So you can not compare frame vs frame a

[Fishman0919]

Sorry, after thinking about it a little more I came back to explain the "blurred" frames further but pg55555 beat me to it ;)

[3ncrypted]

pg55555, thanks so much for typing all that up and explaining it to me. I had a feeling it was ok that the frames were like they were, and that it had something to do with the output from shrink being transcoded and the output from DVDRB being encoded.

Fishman0919, thanks for your help too. Both you and pg55555 have been a big help and have answered quite a few questions that I've had over the past week or so.:)