DVD Shrink and Sharpness

[GParent]

I used DVD Decrypter to rip the DVD of "IN AMERICA" to my hard drive. Then I used DVD Shrink to trim out subtitles and languages. Since the main title is at 100%, I figured there we be no diference between the original MPEG and DVD Shrink's processed MPEG. I was wrong!

It appears, to these eyes, that DVD Shrink has created a sharper image than what exists on the input to DVD Shrink. I am wondering if DVD Shrink is somehow generating what has the appearance of a sharpening filter on the MPEG that it is processing? Also, I am not sure if the sharper image is better than the original.

As an analogy, you can play with the sharpen control on your TV set, and while it may seem improved, you later find other aspects of the sharpened image to be unappealing.

[Joergen]

Not possible. At 100% DVDShrink does not encode the image in any way. It (the lack of processing/encoding) is clearly noticeable by CPU usage and the speed that the data is copied vs. when encoding.

If anything, DVDShrink will slightly reduce sharpness when using encoding.

[Kedirekin]

Perception is a complicated thing. You could both be right.

I agree with Joergen that DVDShrink will not sharpen the image, but the results of it's processing might (sometimes) give the impression of sharping. For example, mosquito noise can appear to have a sharpening affect. So can adding grain. I haven't particularly noticed DVDShrink doing either of these things, but perhaps something else is giving you the impression that the image is sharper.

[dragongodz]

actually its been said many times(even by dvdshrink himself) that if its at 100% there is still a small chance that a tiny bit of compression can be done. this should in no way cause sharpening though.

try setting it to no compression and see if that looks sharper aswell. if yes then thats truly weird since no frames will be compressed for sure then. :)

[GParent]

I have no idea how the A/V streams flow through, and get processed by DVD Shrink's encoding engine. What I do know is that the VOB files are comprised of, video (MPEG-2) and audio (AC3, in the case of IN AMERICA) packets, which are interleaved. Therefore, DVD Shrink is definitely disassembling the original VOB files and reassembling (re-encoding) them. In addition, it is possible that the MPEG-2 stream is being further processed by the transcoding engine, regardless of it needing it or not. Therefore, the encoding engine is applying its properties (look and feel) to that re-encoded stream. Again, its just an opinion, FWIW.

[dragongodz]

DVD Shrink is definitely disassembling the original VOB files and reassembling (re-encoding) them
yes the equivilant of demuxing all the streams and remuxing only the wanted ones. that is NOT re-encoding(i am talking about the no compression setting).

Therefore, the encoding engine is applying its properties (look and feel) to that re-encoded stream
look and feel ? set it to no compression and the frames are retained as-is, there is no "look and feel" applied.

so again i say, try the same dvd with no compression instead of 100% and let us know then if it looks different to you.

[Lagoon]

The answer is quite simple actually.

DVD Shrink = transcoder = CANNOT do ANYTHING other than degrade video quality.

There is no way to gain in sharpness, you can lose some sharpness if you compress a lot 'cause of the blocks.

[dragongodz]

Lagoon - we are talking about the settings of 100% and no compression. so there should be absolutly no degredation at all. especially with the no compression setting since the frames are purely copied, so same as the originals.

[DK64_MASTER]

If you use 100%, there could be compression due to rounding (i.e the compression is 99.95%). Select "No Compression" to make sure its exactly the same. DA couldn't hurt, but its a waste of time at 100%.

[Joergen]

I'd like to add one far off idea to this = When the macrovision signal corruption is removed, the backup might seem sharper on a set combination of player, tv and video signal.

For instance on my old 28" tube macrovision causes a greenish/purplish hue to the top of the image.

Macrovision(R) Quality signal corruption(TM)

btw. I never use "100%" I always tick on No Compression. And no, my CPU cannot transcode at 15 times normal speed (like it does with NO COMPRESSION).

[writersblock29]

<Macrovision(R) Quality signal corruption(TM)>

Joergen makes a pretty good point: I've seen that "greenish hue" on one of my televisions, too -- but on the same TV, it's not there when I watch a copy rather than the original.

<I agree with Joergen that DVDShrink will not sharpen the image, but the results of it's processing might (sometimes) give the impression of sharping. For example, mosquito noise can appear to have a sharpening affect. So can adding grain. I haven't particularly noticed DVDShrink doing either of these things, but perhaps something else is giving you the impression that the image is sharper.>

I've got movies that gave me the impression that the copy was sharper -- only to find out that the mosquito noise present on the original was just made plainer, giving the copy more of a "busy" look. So for copies requiring Shrink to compress something, I'd say Kedirekin brings up a good point. (Hell, even for footage with NO compression: honestly, how closely do you study the original footage? It's usually the COPY that you put under the microscope. It's really easy to trick yourself into seeing something that isn't there.)

[cereal killa]

Maybe the default when no compression is needed should be "no compression" instead of 100%