Does DVD Shrink loose any quality at 100%?

[mcka]

Hi!

When I use 100% quality in DVD Shrink, does DVD Shrink pass the MPEG2 files 1:1 from DVD, oder are they encoded again? If I set 99%, the VOB files have to be encoded again. But does DVD Shrink switch to a "different mode" for 100% (passing the files without encoding MPEG2 again)? So am I loosing Quality at 100% using DVD Shrink?

What about DVD Decrypter and DVDFab Decrypter? Do all the tools deliver exactly the same Quality like DVD Shrink at 100%, or is there any difference?

best regards
mcka

[bourtzovlakas]

No difference at 100%....

[mcka]

thanks!

[techreactor]

Hi!

When I use 100% quality in DVD Shrink, does DVD Shrink pass the MPEG2 files 1:1 from DVD, oder are they encoded again? If I set 99%, the VOB files have to be encoded again. But does DVD Shrink switch to a "different mode" for 100% (passing the files without encoding MPEG2 again)? So am I loosing Quality at 100% using DVD Shrink?


No loss of quality but it does encode the files again, without applying any compression at 100%


What about DVD Decrypter and DVDFab Decrypter? Do all the tools deliver exactly the same Quality like DVD Shrink at 100%, or is there any difference?

best regards
mcka

Both of these are rippers and DVD shrink is a transcoder i.e. they are functionally different, although DVD shrink can also rip if the ArccOS protection in not present.

[Jay Bee]

No loss of quality but it does encode the files again, without applying any compression at 100%


How is this possible? It either encodes/compresses or it doesn't. Unless you mean lossless encoding which would make the DVD 50 GB.

[niknik]

How is this possible? It either encodes/compresses or it doesn't. Unless you mean lossless encoding which would make the DVD 50 GB.

I supose he means reencoding as in: removing unselected audio tracks/ subtitles. The video stream itself remains untouched (and therefore no quality loss)

[mcka]

How is this possible? It either encodes/compresses or it doesn't. Unless you mean lossless encoding which would make the DVD 50 GB.
Hm, that's why I asked here ;-)

When I "transcode" a DVD with 100%, DVD Shrink only takes about 5 Minutes. If I compress to 70%, it takes longer.

I've found that thread:

http://forum.doom9.org/showthread.php?t=76582

So if I choose "no compression", it definitly does not do any encoding, but copies the files, so makes the same like the other mentioned rippers? In the thread someone says, that DVD Shrink encodes at 100%. Can someone confirm that?

[CWR03]

So if I choose "no compression", it definitly does not do any encoding, but copies the files, so makes the same like the other mentioned rippers? In the thread someone says, that DVD Shrink encodes at 100%. Can someone confirm that?
Your assumption is correct; the one that says it encodes at 100% is wrong. It simply copies the files, omitting the deselected ones.

[techreactor]

let me be more clear, "encoding was only a notion", it doesnt encode but copies the source to the destination folder bit by bit, in the sense rewrites but without any changes to the source files.

[Synetech]

let me be more clear, "encoding was only a notion", it doesnt encode but copies the source to the destination folder bit by bit, in the sense rewrites but without any changes to the source files.

That’s not quite true. If you compare the original and resulting VOB files, even at 100%, there will still be some differences here and there (the files are not 100% identical).

[setarip_old]

@SynetechThat’s not quite true. If you compare the original and resulting VOB files, even at 100%, there will still be some differences here and there (the files are not 100% identical).Not if you select "No Compression"...

[Synetech]

@SynetechNot if you select "No Compression"...

I’d have to check to say for sure, but I’m fairly certain, yes, even with No Compression. The frame data may be the same, but the files are not. If you do a binary comparison (fc /b src\VIDEO_TS\VTS_01_1.VOB dest\VIDEO_TS\VTS_01_1.VOB), it will have differences here and there. From what I have read, it doesn’t copy the files, it copies the frames, so while the data that comprises the frame contents is identical (the majority of the file), the metadata that describes the frames is not identical because even within a standard, there is room for difference. It’s like when you take two “identical” MP3 files and compare them and find that while the audio data is indeed the same, there are differences caused by for example MP3Gain or some other thing.

[setarip_old]

As far as I know, with "No Compression", the only possible differences may occur due to settings chosen, such as "Turn off PUOs"...

[Synetech]

As far as I know, with "No Compression", the only possible differences may occur due to settings chosen, such as "Turn off PUOs"...

Wouldn’t those be in the IFO? I’m talking about differences in the VOB. I’ll do a test some time today to check, but I’m fairly sure I’ve seen it happen.

[fib0by]

Please use the correct language.

At 100%, the video and audio tracks are de-multiplexed first. The tracks per se remain untouched. They are then re-multiplexed in a new DVD image. What changes is the container, not the video/audio tracks. It's called re-multiplexing.

Also, when actually shrinking the video, what DVD Shrink does is not "re-encoding". That would imply the MPEG2 is decoded to raw format, then re-coded with an MPEG2 encoder. That is not what happens.
What happens is that the MPEG2 track is re-quantized. That is a way to reduce the bitrate of an MPEG2 stream without going through the raw format.

The word "encoding" (or "recoding") is used in the wrong way on this forum. Please do not confuse anymore (re)encoding with requantizing.

[Southstorm]

In a nutshell, If you want a bit for bit copy, use NO Compression setting. I have faith that even with a miniscule difference in file size, I'm getting what I want.

[setarip_old]

@fib0by

Hi!

Who are you addressing?

The last 5 posts to this thread, which are the only ones less than 1 year old, don't discuss encoding, recoding, transcoding, etc...

BTW - The DVD Shrink setting for "No compression" is different than simply setting it to "100%". The "No compression" setting results in a direct copy (no demuxing and remuxing)

[blutach]

PUOps can also exist in the VOBs and therefore if these exist on the original and you choose to have them off, even at "no compression" the output will differ slightly from the input (every navpack will be different for example).

Regards

[Synetech]

PUOps can also exist in the VOBs and therefore if these exist on the original and you choose to have them off, even at "no compression" the output will differ slightly from the input (every navpack will be different for example).
Ah, well then that sounds about right.

[blutach]

Of course, you can also set no compression and strip streams, and while the video (and the kept streams) will be the same, the VOBs will be entirely different. This is the demux/remux process that fib0by talked about.

Note, it is not a full remux. The PTMs are not changed, for example. The way to do this properly is to start off with elementary streams and mux them with muxman, for example.

Regards

[donburkard@temple]

ok i read all that and relixe i have no idea what the H#(( you guys are talking about! so which is going to give you a better quality. no compression or 100%? will you even be able to see a difference in the end result? can i create .iso's with both option?

[Southstorm]

"NO Compression" is bit for bit identical. You probably won't see the difference, but that's besides the point.

[Synetech]

ok i read all that and relixe i have no idea what the H#(( you guys are talking about! so which is going to give you a better quality. no compression or 100%? will you even be able to see a difference in the end result? can i create .iso's with both option?

No compression means just that, copy it without compressing it. As mentioned above, 100% could be round up (Shrink only shows one decimal place), so it could still be compressing a bit. Granted, it probably won’t make any difference, and if it’s that close to 100% (which is just an estimate anyway), chances are it will end up not compressing, but if it will fit, you should just select no compression.