Recode 2 and Dvd Shrink (a personal opinion)

Started by bluewater, January 08, 2007, 16:03:49

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Oso Blanco

I see what you mean. I spent hours and hours searching for torrents to download some DVDs that I need. But it's almost impossible to get them un-shrinked. Can be pretty annoying, I agree.
Time is the fire in which we burn ...

bluewater

Quote from: Oso Blanco on March 04, 2007, 08:36:24
Just to make sure I understand you: You mean, that DVD Shrink re-encodes the DVD even if I chose not to compress anything at all? If I only drop the menues and some language tracks, the DVD will not be re-encoded or will it?

I don't believe these programs i mention (recode 2 and dvd shrink) re-encode, they
drop less significant frames or something else psychologically so one don't see
the difference very well. At least recode 2 doesn't add blocky artefacts, but
it drops too much frames in moving scenes so the movement is less fluent. So it looks
like it affects the framerate. Dvd shrink adds blocky artefacts. I have no scientific
proof so what i say is not scientific, only based on personal experience. And i think
what these programs do is very insufficiently documented, so it is not healthy to
use them in anything related to trading or collecting.

bluewater



Life's too short to listen to lossy music

lostflower4

What I understand is that some programs only re-encode certain frames. In other words, it drops the bitrate on some frames, while leaving others as-is. I don't think it's "legally" possible to change the framerate of a DVD. It must either be 25 (PAL) or 29.97 (NTSC).

So this "partial re-encoding" may hide some of the nastiness of full-borne re-encoding, but it's still bad stuff to me. :smth011

If you see less fluid of motion from this practice, I would guess it has to do with the awkward bitrate variation, or something along those lines â€" but I seriously doubt that the framerate itself is changed.

bluewater

Quote from: lostflower4 on March 04, 2007, 15:08:50
What I understand is that some programs only re-encode certain frames. In other words, it drops the bitrate on some frames, while leaving others as-is. I don't think it's "legally" possible to change the framerate of a DVD. It must either be 25 (PAL) or 29.97 (NTSC).

So this "partial re-encoding" may hide some of the nastiness of full-borne re-encoding, but it's still bad stuff to me. :smth011

If you see less fluid of motion from this practice, I would guess it has to do with the awkward bitrate variation, or something along those lines â€" but I seriously doubt that the framerate itself is changed.

Yes, the framerate is not changed, of course. It only looks like it would drop because human eye sees the drop in information rate in the same way as a drop in framerate.
And that partial re-encoding theory probably holds as well.

bluewater
Life's too short to listen to lossy music

japanesebaby

i must agree to what's been said here.
the problems that all this shrinked stuff causes especially on torrents these days are massive.  :smth011
many times i've even seen dvds re-seeded after someone's first felt the strange urge to shrink them first - and these in situations where not even re-authoring would have been required. so unless people wanted to make it look worse and also get rid of the original menu and proper chaptering in the process.... ok, i really don't get what the benefits were supposed to be.

and yes it's very common on many torrented dvds that the aspect ratio especially is flagged all wrong, this happens all the time. almost every other dvd one downloads is like this sometimes: people look freaking thin and squeezed. but there's IFOedit that can handle this problem literally in one second, still one sees people posting instructions saying "hey you can easily reconstruct this with DVdshrink!" - and judging from the instructions i've seen, that would include re-encoding (=completely useless).
trying to change the framerate is a different thing, of course.

and "partial re-encoding" - sounds like someone trying to hide their filthy hazy tracks.... which is all that it is in the end. :( 


(ja heipä vaan oulun suuntaan, pitkästä aikaa  :smth001 )
Ay, in the very temple of Delight
Veil'd Melancholy has her sovran shrine

lostflower4

Another argument against DVD shrinking and the like... I don't think everyone realizes that all DVD videos are lossy to begin with. MPEG-2, the standard that DVD video is based upon, is a lossy format. On a mathematical level, one could say that it's extremely lossy.

As I've stated previously, the bitrate of uncompressed standard definition video is over 100 Mbps. A "good" DVD bitrate usually varies between 5-8 Mbps. To put that in perspective, the bitrate of an audio CD is about 1.4 Mbps. FLAC can usually get this down below 1. And then you've got mp3 which is just a small fraction of this.

In other words, lossless video is HUGE and generally unpractical to use as an end format. Maybe in a few years the storage requirements won't seem so daunting. But then again, we're already in the age of high definition, which requires a lot more bitrate â€" so lossy video is likely something we'll be seeing for many years to come. :?

MPEG-2 isn't a perfect format, but it looks very good when properly encoded. And just that alone takes a little work. So when someone just goes in to blindly DVD Shrink something (which makes everything double-lossy, as I've explained), it almost makes me sick to think about. :(


bluewater

Just a side note. The reason why more efficient standard than mpeg-2 is needed is the need for a higher resolution. The resolution limits the quality in the same way as the sampling rate affects the quality
of lossless audio. So even if a video stream is lossless, the resolution limits
it causing blur or lack of detail. I think everyone would want mpeg-2 full dvd resolution
vs. "lossless" low resolution (352x288). The reason why more efficient
standard than mpeg-2 is already coming is hdtv that uses higher resolution than dvd.
Many professionals would claim that mpeg-2 is getting old if compared to high-resolution
(hdtv) mpeg-4. I think dvd- resolution is where mpeg-2 reaches it's limits, going
to higher detail (higher resolution) demands higher standard (mpeg-4)?

A good measure for the limits of encoding or even "blockiness measure" is the so called Bits/pixel*frame ratio. This ratio can be lower with mpeg-4 (meaning more detail or higher resolution) than with mpeg-2.

bluewater

edit: so one has to be sacrificed,
- resolution
- framerate
- bitrate
- color depth

if bitrate must be lowered or be kept in certain limits (for higher resolution but reasonable sizes), then what must be changed is
- standard (tendency being towards mpeg-4 from mpeg-2, i think)
Life's too short to listen to lossy music

Oso Blanco

Quote from: japanesebaby on March 04, 2007, 16:46:20
so unless people wanted to make it look worse and also get rid of the original menu and proper chaptering in the process.... ok, i really don't get what the benefits were supposed to be.

Personally, I find those animated menues annoying. And I'm trying to get rid of them whenever I copy a DVD. The chaptering is not being changed with DVD Shrink at all.

Quote from: japanesebaby on March 04, 2007, 16:46:20
people look freaking thin and squeezed.

That's called "anamorphic widescreen".

Quote from: japanesebaby on March 04, 2007, 16:46:20
"hey you can easily reconstruct this with DVdshrink!"

DVD Shrink cannot reconstruct anything.

____________________________________________

Again: It all depends on what you are going to do with your DVD. If you want an exact copy of the original movie which you want to keep as a part of your collection, it should be unshrinked and kept as original as possible. But if you are just making a copy to watch the movie once or perhaps twice, I don't see why one shouldn't shrink the movie so that it fits onto a single layer DVD.
Time is the fire in which we burn ...

Oso Blanco

Quote from: bluewater on April 11, 2007, 15:34:04
Just a side note. The reason why more efficient standard than mpeg-2 is needed is the need for a higher resolution. The resolution limits the quality in the same way as the sampling rate affects the quality
of lossless audio. So even if a video stream is lossless, the resolution limits
it causing blur or lack of detail. I think everyone would want mpeg-2 full dvd resolution
vs. "lossless" low resolution (352x288). The reason why more efficient
standard than mpeg-2 is already coming is hdtv that uses higher resolution than dvd.
Many professionals would claim that mpeg-2 is getting old if compared to high-resolution
(hdtv) mpeg-4. I think dvd- resolution is where mpeg-2 reaches it's limits, going
to higher detail (higher resolution) demands higher standard (mpeg-4)?

A good measure for the limits of encoding or even "blockiness measure" is the so called Bits/pixel*frame ratio. This ratio can be lower with mpeg-4 (meaning more detail or higher resolution) than with mpeg-2.

I have an HD file on my hard drive that is MPEG2, so I don't think that you would necessarily need MPEG4 to achieve an HD resolution.

By the way, do you happen to now a free program which I can use to convert the resolution of this file from HD to PAL?
Time is the fire in which we burn ...

lostflower4

Quote from: Oso Blanco on April 16, 2007, 14:37:14By the way, do you happen to now a free program which I can use to convert the resolution of this file from HD to PAL?

Convert from HD to PAL? That doesn't make any sense.

And: Why not keep it in HD? Why is it always necessary for people to alter things and make them worse?

Oso Blanco

Quote from: lostflower4 on April 16, 2007, 14:39:41
Convert from HD to PAL? That doesn't make any sense.

Yes, it does. Because I don't have an HD-DVD-Player. And I'm not sure if there are HD-DVD-Rs available yet ...

Quote from: lostflower4 on April 16, 2007, 14:39:41
And: Why not keep it in HD? Why is it always necessary for people to alter things and make them worse?

I don't want to make it worse, I just want to be able to watch that movie on my TV!
Time is the fire in which we burn ...

lostflower4

Quote from: Oso Blanco on April 16, 2007, 14:47:25
Quote from: lostflower4 on April 16, 2007, 14:39:41
Convert from HD to PAL? That doesn't make any sense.

Yes, it does. Because I don't have an HD-DVD-Player. And I'm not sure if there are HD-DVD-Rs available yet ...

No, it doesn't make any sense. There are these formats:

High definition NTSC
High definition PAL

Standard definition NTSC
Standard definition PAL

And so forth...

So saying "convert from HD to PAL" is kind of like saying "convert blue to banana". :lol:

But to answer your question, I don't have a clue â€" other than to buy a Blu-Ray or HD DVD player/burner.

Oso Blanco

Yes, it's HD NTSC ... but the conversion from NTSC to PAL shouldn't be that tough, so what I meant to say is that I'm looking for something that can convert HD to Standard ... in this case PAL.

I have already found one program that can do it, but my computer is not powerful enough to handle it. I wonder if there might be an easier way to do it.
Time is the fire in which we burn ...

lostflower4

Well, it's the same old thing for me. High definition broadcasts are lossy, so any further conversions is just going to make them worse. I wouldn't mess with it.

Converting region standards is also messy when you're dealing with files that are already lossy, not something for me.

Plus, I don't have a clue about working with high def stuff. I personally would just watch it on my computer and wait for the price of HD hardware and media to come down a bit more.

Oso Blanco

Quote from: lostflower4 on April 16, 2007, 15:18:39
Well, it's the same old thing for me. High definition broadcasts are lossy, so any further conversions is just going to make them worse. I wouldn't mess with it.

I have no idea how lossy the broadcast is, the file is about 8 GB, Video: 1920x1080, 29.97fps, 19400Kbps; Audio: Dolby AC3, 48000Hz, 6ch, 448Kbps. Seems pretty good to me, but I'm no expert in DVDs, let alone HD-DVDs.

Quote from: lostflower4 on April 16, 2007, 15:18:39
Converting region standards is also messy when you're dealing with files that are already lossy, not something for me.

I know ... I'm not yet sure wheather or not just to keep it NTSC. I can watch both PAL and NTSC on my DVD/TV. But the NTSC version seems to be a little slow.

Quote from: lostflower4 on April 16, 2007, 15:18:39
I personally would just watch it on my computer and wait for the price of HD hardware and media to come down a bit more.

My computer ist too weak to handle even normal DVDs! And I think it will be a few years until I can afford any of this HD equipment.
Time is the fire in which we burn ...