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brewbuck
02-11-2008, 12:37 PM
Just a general complaint. Videos are already compressed. Rar'ing it is not going to make it that much smaller. Now I have to use some proprietary decoder. And on top of that, when disk space is tight, you end up needing twice as much -- 50% to hold the rar, the other 50% to hold the decompressed result.

I made that mistake a few times -- I've got, say, 600 meg free, so I download a 500 meg archive. Whoops -- no space to decompress it. And the stupidity of it is that the compressed version isn't even that much smaller. (Don't laugh at my lack of disk space -- I use small partitions to discourage myself from hoarding stuff.)

Dumb dumb dumb.

(And no, I'm not downloading pirate videos, just random weird stuff)

Elysia
02-11-2008, 01:00 PM
I don't know why they do. They're dumb, maybe?
But I also agree with you, I too, find it annoying. Disk space isn't that much of an issue, but it takes such a long time to uncompress it.

Sang-drax
02-11-2008, 01:19 PM
I completely agree. RAR is stupid.

It has to do with ensuring that a release is unmodified since its release. Here's a page that tries to explain why: <http://whyrar.omfg.se/index_eng.php>. I still think RAR is stupid, though.

Mario F.
02-11-2008, 01:40 PM
Seems odd their explanatiopn since it's just as easy to create a crc from a non-archive.

The idea if something gets corrupted, it cuts down downloading times, is correct I guess. However, any P2P program these days does all manner of checks to make sure data is being correctly downloaded and data traveling over broadband connections (only connection that matters for these things, really) is notoriously reliable.

maxorator
02-11-2008, 01:45 PM
It seems to be just a stupid habit. :p

Mario F.
02-11-2008, 01:52 PM
It seems to be just a stupid habit

My vote too.

twomers
02-11-2008, 01:54 PM
It might have something to do with being able to password correct or maybe split files.
But neither of those are good reasons. There are many free file splitters and protectors. Perhaps the offenders don't know the negligible effect and actively practice hoarding.

abachler
02-11-2008, 01:59 PM
RAR is much better than ZIP. ZIP is very poor compression for one, and it lacks a lot of other features that RAR has. RAR has been around for ~15 years so its not like its some new standard. RAR can handle error correction, volume splitting, opens more file types, has a lot of backup features, and is just as free as winzip. Another nice feature of RAR is you can create recovery volumes AFTER the fact.

I haven't seen you give one reason why ZIP is better than RAR.

As far as RARing video's, RAR can compress an MPEG4 by an additional 10% on average. may not seem like much to you, but it means a lot to the guy paying the bill for the website that is hosting the files.

mike_g
02-11-2008, 02:10 PM
Err.. No-one here said that Zip was better than RAR :p

AloneInTheDark
02-11-2008, 02:13 PM
it's simple, they are morons.
:)

abachler
02-11-2008, 02:17 PM
Err.. No-one here said that Zip was better than RAR :p

and out of 2 paragraphs of post, that is the one sentence you picked up on...

As far as splitting an archive, there are a lot of good reason to do so. Ease of upload, ease of download, recovery volumes can only be made for split archives, etc.

Elysia
02-11-2008, 02:36 PM
RAR is much better than ZIP. ZIP is very poor compression for one, and it lacks a lot of other features that RAR has. RAR has been around for ~15 years so its not like its some new standard. RAR can handle error correction, volume splitting, opens more file types, has a lot of backup features, and is just as free as winzip. Another nice feature of RAR is you can create recovery volumes AFTER the fact.

I haven't seen you give one reason why ZIP is better than RAR.

As far as RARing video's, RAR can compress an MPEG4 by an additional 10% on average. may not seem like much to you, but it means a lot to the guy paying the bill for the website that is hosting the files.
Only 7zip beats rar in compression. So rar is just poor now.
And I very much doubt you can compress a video an additional 10%. That's very hard to believe unless proof is shown up front.


As far as splitting an archive, there are a lot of good reason to do so. Ease of upload, ease of download, recovery volumes can only be made for split archives, etc.

These things are usually distributed through P2P due to the bandwidth. And when sharing through P2P, none of these are advantages at all...

abachler
02-11-2008, 02:44 PM
Only 7zip beats rar in compression. So rar is just poor now.
And I very much doubt you can compress a video an additional 10&#37;. That's very hard to believe unless proof is shown up front.

7zip only beats rar on some types of compression, only by a negligeable amount, and not all the time.

I just compressed an MPEG4 stream coming form a camera and got 33% compression. (67% of original size).

The files are on my website
Original File - http://www.anthonyqbachler.com/mpeg.asf
Compressed file - http://www.anthonyqbachler.com/mpeg.rar

Ill post the files on my website this evening.



These things are usually distributed through P2P due to the bandwidth. And when sharing through P2P, none of these are advantages at all...

reduced bandwidth is an issue, even if it isnt costing you extra $. It speads up the process. Recovery volumes are also a benefit since they allow you to fix any errors in the original file that werent caught before distro.

Elysia
02-11-2008, 02:59 PM
I just compressed an MPEG4 stream coming form a camera and got 33&#37; compression. (67% of original size).

I did a test on a 77 MB MPEG4 AVC High Profile Unlimited Level Video.
Original size: 77 MB (80 776 639 bytes).
RARed size: 77 MB (80 743 479 bytes, saved 33 160 bytes [0.04%]).
7ziped: 77.5 MB (81 317 718 bytes, saved -541 079 bytes [-0.67%]).

abachler
02-11-2008, 03:22 PM
Supply the original file so others can verify your results?

Elysia
02-11-2008, 03:24 PM
Umm well, it's really big, 77 MB.
Don't have a hosting so I'll need to choose one first and upload... and that's... slow >_<
Anyhow, why not try some heavy compression files yourself?

Mario F.
02-11-2008, 03:32 PM
Supply the original file so others can verify your results?

She doesn't need to. Those are expected results for that file type.

abachler
02-11-2008, 03:50 PM
No offence Mario, but your word doesn't carry a lot of weight with me. Im certainly willing to go through the trouble of verifying her results, but since I posted the files I used, I expect the same courtesy in return.

Elysia
02-11-2008, 03:52 PM
Name a good upload service with ftp (ftp because uploading is slow, since my connection is limited to 60 kb/s up) and I'll upload tomorrow. Otherwise I have to scourge the web for one and then upload it.

abachler
02-11-2008, 03:59 PM
Not really sure, I have a hosting service that I use, but it doesnt allow anonymous ftp upload. Perhaps you could just find some suitable source already on the net that we could compare results from. I suggest Globat.com if you are looking to get a host. Im switchign to them when my current contract runs out.

Oysterman
02-11-2008, 04:01 PM
You could always use Megaupload:

http://www.megaupload.com

(Though it's over HTTP.)

EDIT: FWIW, I rar:ed a couple of .avi files, the rar's were both 10-15&#37; smaller (with max compression). I could upload them for verification, if requested.

Elysia
02-11-2008, 04:02 PM
I'm not looking for a host right now. I had one that gave 10 or 100 or so webspace, I can't remember, but I let it expire since I just had nothing to put on the hosting.
So, some source of the web, huh? Speedruns maybe?
I'll try. Let me do a test on one of the files I have.


You could always use Megaupload:
http://www.megaupload.com
(Though it's over HTTP.)
Yeah, I know of that one as well as rapidshare. Only problem is that I don't want to upload via HTTP since I can't see when it's finished and I can't pause/resume and it will take forever, so I can't close the page and I can't resume if it fails, etc. That's why I prefer FTP.

Wraithan
02-11-2008, 04:06 PM
In most cases, people have already compressed the video before it is RAR'd/7zip'd/ZIP'd so the effects of a second compression is negligable, the point of the OP was that no type of compression is much better than typical video compression. That is not to say if you take a near raw feed (such as your video camera, which can not compress as well due to the video streaming in) it wont compress, but once you run a single pass or double pass filter over it, you will get the about as small as it is going to get. (EDIT: without losing quality that is)

Also I don't know much about RAR but 7zip, you have to get the settings right for the type/size of file you are compressing, proper setting you can get a lot better compression than just default.

Mario F.
02-11-2008, 04:07 PM
Maybe wraithan word carries more weight abachler. Will you care to listen to him?

Elysia
02-11-2008, 04:08 PM
I'm using "Best" compression for both, so no problems there.
First test for this file shows 3&#37; compression gain with 7zip (306 MB vs 314 MB).
As for rar, 2% compression gain (308 MB vs 314 MB).

File:
http://ia300134.us.archive.org/1/items/MetroidPrime_100p_128/MetroidPrime_100p_128_HQ_part04.avi

For tomorrow's test, I'll recompress the file (video compression) and recompress using both rar and 7z again.

Oysterman
02-11-2008, 04:31 PM
Yeah, I know of that one as well as rapidshare. Only problem is that I don't want to upload via HTTP since I can't see when it's finished and I can't pause/resume and it will take forever, so I can't close the page and I can't resume if it fails, etc. That's why I prefer FTP.

Well, Megaupload has a flash-based progress indicator that works fine for me, at least. No resume functionality AFAIK, though.

zacs7
02-11-2008, 04:41 PM
So it'd be really bad if we, rar'd a video, zipped the rar'd video, 7zipped the zipped rar'd video? :)

abachler
02-11-2008, 04:42 PM
OK, im dling that file, although its not exacly MPEG4, which is what my original claim was, Ill see what I can do with it.

and when we are done with all that lets ARJ it just to be ........heads :D

OK I finished DLing it and heres the results I got

Original File - 330,127,360
Compressed- 323,773,272

Savings 6,354,088

overall compression ratio 98&#37; (98.07%).

Sang-drax
02-11-2008, 06:06 PM
I just compressed an MPEG4 stream coming form a camera and got 33% compression. (67% of original size).Hehe, well, you should try a more representative video stream and not one minute of unchanged video. :D I am not surprised that RAR was able to compress that video stream well.

For those interested, the video he used was a view out from a window where nothing was changing except cars in the distance.

brewbuck
02-11-2008, 08:17 PM
Supply the original file so others can verify your results?

Right. Because Elysia is just making it up. Paranoid much?

Elysia
02-12-2008, 12:42 AM
Oh, it's MPEG4 alright. DivX to be exact. It's also MPEG4 and an AVI container.
Let's see how it fares against MPEG4 AVC, shall we?

UPDATE:
And the results are in. RAR: 150 MB vs 150 MB.
7zip: 152 MB vs 150 MB.
I can instruct how to recompress and verify these results, if you want.
But it goes to show that compressing a video using good video compressing yields in little or no saved space.

indigo0086
02-12-2008, 07:29 AM
weird random 600mb videos...
sure buddy.

abachler
02-12-2008, 09:23 AM
except again, you are choosing specific examples, whereas I have also shown examples that show excellent compression adn are also Mpeg4. Your claim is that they compress little or not at all, where I have shown that not to be the case. I can show you just as many examples where Mpeg4 does compress as you can show that it does not. You are taking a few specific examples where the Mpeg4 was highly compressed to begin with and makign a broad sweepign statement that those examples are representative of MPEG4 as a whole. I have shown that they are not.

Wraithan
02-12-2008, 10:11 AM
Or one could turn the tables on you and say you are hand picking your videos to be not compressed much, so that it would show you to be correct. Fact of the matter is, most times people share media across the net, especially audio and video, it is compressed to the point that using a standard file compression program is frivolous. Take anime for example, I have about 150gigs of anime, and about 150 gigs of that wont compress worth a damn if I ran it through 7zip, RAR, or what ever compression software you want to use.

brewbuck
02-12-2008, 10:22 AM
It's funny watching you guys argue about this... Kind of like choosing which color of racing stripe to put on your Civic. If reducing the size of a file by a few percent makes you feel like a badass I guess that's cool.

Elysia
02-12-2008, 10:23 AM
except again, you are choosing specific examples, whereas I have also shown examples that show excellent compression adn are also Mpeg4. Your claim is that they compress little or not at all, where I have shown that not to be the case. I can show you just as many examples where Mpeg4 does compress as you can show that it does not. You are taking a few specific examples where the Mpeg4 was highly compressed to begin with and makign a broad sweepign statement that those examples are representative of MPEG4 as a whole. I have shown that they are not.

I've chosen files that represent about 90% of the material on internet. Every video you come across, except really old ones, uses either Xvid, DivX or H264, usually x264.
MPEG4 ASP compresses about 2-3% and H264 pretty much none.

brewbuck
02-12-2008, 10:33 AM
except again, you are choosing specific examples, whereas I have also shown examples that show excellent compression adn are also Mpeg4. Your claim is that they compress little or not at all, where I have shown that not to be the case. I can show you just as many examples where Mpeg4 does compress as you can show that it does not. You are taking a few specific examples where the Mpeg4 was highly compressed to begin with and makign a broad sweepign statement that those examples are representative of MPEG4 as a whole. I have shown that they are not.

How is Elysia's limited and probably unrepresentative sample any different than your limited and unrepresentative sample? If this is really a question you are interested in answering (I'm not), you ought to download a few hundred randomly chosen video files and do a real test. The problem is the "randomly chosen" part. As far as I know there is no method of randomly sampling a video from the Internet with no statistical bias. And how would you weight your sampling distribution? By file size? Uniformly? By number of downloads per day?

Regardless of whether RAR can actually make the file smaller, it still requires me to have a RAR dearchiver as well as extra disk space in order to decompress the file. A few extra bytes of file size is a small price to pay to not have to deal with that pain in the butt.

abachler
02-12-2008, 11:23 AM
You have to have some kind of dearchiver to begin with, so that complaint is mute. It is common practive to compress files for distribution. Once you have spent the time to compress the file there is no good reason not to distribute the smaller of compressed/uncompressed. The situation where you do not have enough disk space to decompress the file is rare. I would hazard that 99.9&#37; of users have plenty of extra space to decrompress. If you are that low on disk space then perhaps the real issue is why you havent upgraded to a larger HDD.

Decompressing a RAR is just like opening a folder. WinRAR doesnt fully decompress the entire image, just the directory, so you can see whats there before decompressing it. I realyl don't see how that is any more of a pain in the butt than using an uncompressed file. Particularly if you are so low on disk space as you claim to be, you shoudl be keeping all yoru files in compressed archives and only decompressing the ones you need to use.

As for the limitation in the samples, its simple. She claims that A cannot B because C. I show an example D where A can B. Therefor her argument that A cannot B is false by counterexample regardless of how unrepresentative C and D are.

laserlight
02-12-2008, 11:36 AM
It is common practive to compress files for distribution.
I think Wraithan already addressed this point: "In most cases, people have already compressed the video before it is RAR'd/7zip'd/ZIP'd so the effects of a second compression is negligable, the point of the OP was that no type of compression is much better than typical video compression."

An anology for (open source) software would be compressing a compressed tarball.

Elysia
02-12-2008, 11:47 AM
As for the limitation in the samples, its simple. She claims that A cannot B because C. I show an example D where A can B. Therefor her argument that A cannot B is false by counterexample regardless of how unrepresentative C and D are.

So what are implying is that my test case is pretty irrelevant simply because there are other compressions out there can be far better compressed?

abachler
02-12-2008, 11:59 AM
So what are implying is that my test case is pretty irrelevant simply because there are other compressions out there can be far better compressed?

Not irrelevant, just not deterministic.

The reason that it is common practice to compress files before distro is that they usually DO compress and once the processing time has been spent to compress them, even a small savings in size makes it better to distribute the compressed version. So essentially the cost to use the compressed versus uncompressed is zero and any savings in bandwidth is free. I'm not saying that MPEG4 cannot achieve good compression, I am saying that for a lot of reasons it is usually not the case that mpeg4 files are compressed at their highest settings and that RAR can usually achieve some improvement. This improvement can range from 2&#37; in elysia's example to 33% or more as in my example. I figure that '10% on average' is a good rule of thumb then.

Elysia
02-12-2008, 12:02 PM
Yes, of course, but a few kilobytes saving is nothing. It all depends on the compression used, because video compression is far better at saving size than compression utilities. And as shown, with H264 and very high compression settings, compressing it using winrar saves nothing. It's just a waste of time.

abachler
02-12-2008, 12:18 PM
As I stated, video is not always compressed using the highest settigns for various reasons of quality/speed. Therefor it is prudent to at least TRY to compress the video first. Once the RAR ( or zip etc) compression has been performed, there is no reason not to use the smaller of the compressed or uncompressed versions. 2&#37; may not seem like much, but its enough to save on the upload time which is realyl what most distributers are worried about.

vart
02-12-2008, 12:41 PM
Also - if archive is password protected - it will NOT be scanned by the Antivirus software on server and on Firewall, saving the CPU/HDD access times on server

Elysia
02-12-2008, 12:50 PM
As I stated, video is not always compressed using the highest settigns for various reasons of quality/speed. Therefor it is prudent to at least TRY to compress the video first. Once the RAR ( or zip etc) compression has been performed, there is no reason not to use the smaller of the compressed or uncompressed versions. 2% may not seem like much, but its enough to save on the upload time which is realyl what most distributers are worried about.

For quality reasons? The only argument against heavy video compression is decoding speed and encoding time.
Still, if you encode using MPEG4 ASP/AVC, it's hardly worth the time compressing it. For other sources, perhaps... but 90% of the material is MPEG4 ASP/AVC.

Mario F.
02-12-2008, 01:19 PM
2% may not seem like much, but its enough to save on the upload time which is realyl what most distributers are worried about.

Squeezing 2% of the file size seems like an argument. But it isn't. They rar the thing and split the rar because that's how they do it. Period.

It's the stupid habit idea. Nothing wrong with it. Files were being RARed and split long before video files had such an high rate of compression. They just do it this way because that's what they have been doing for years.

The 2% used to be important. Not anymore on non centralized p2p networks. So yeah, again, it's an habit. Sheesh!

abachler
02-12-2008, 02:37 PM
You seem to think that p2p == infinite bandwidth, it does not. The file is still going over finite connection speeds and the smaller the overall file, the faster it will transfer. Perhaps 2% doesnt matter on a 1MB file where the difference woudl mean only a second or two, but particularly on large files, 2% of a 4 hour download means it finishes several minutes earlier.

You have taken the stance that 'oh its stupid they have no reason to do it' and simply refuse to accept any of the reasons presented because they disagree with your notion that they do it because they are stupid.

Elysia
02-12-2008, 02:44 PM
Should we take into the account the power it takes to unrar that crap then (and the time; of gods, the time it takes, especially on a slow machine!)? It can probably cost just as much as the bandwidth providers for that little extra MB or two.
Hehehe... I'm trolling, but I don't see the need for compressing to save a MB or two when it's just 2-3&#37; save.

Mario F.
02-12-2008, 02:52 PM
You have taken the stance that 'oh its stupid they have no reason to do it' and simply refuse to accept any of the reasons presented because they disagree with your notion that they do it because they are stupid.

Yes. I think it's (today) a stupid and annoying habit that got popular probably from the earlier days of usenet sharing.

I presented my reasons, too. 2% of a 4GB file is ~80Mb. This is nothing on today's broadband networks. You get that much from just surfing the web. On my ADSL 12Mbps, 80Mb takes me 5 minutes on a bad day.

abachler
02-12-2008, 02:56 PM
Should we take into the account the power it takes to unrar that crap then (and the time; of gods, the time it takes, especially on a slow machine!)? It can probably cost just as much as the bandwidth providers for that little extra MB or two.
Hehehe... I'm trolling, but I don't see the need for compressing to save a MB or two when it's just 2-3&#37; save.

And as Ive shown, its not alwasy 2% which necessitates the process of compressing first, then comparing the results, then using the smaller file.

If it takes you more than 5 minutes to decompress a 4GB RAR then you need to get rid of your 386SX and find somehting newer. Belly-aching because you have a modern connection and an antiquated system is not a plausable reason to expect everyone else to spend more time downlaoding files.