Capture For DVD? Here is What you must be Aware...

[macm]

From the ISO MPEG-2 specification:

1. (...) "contrary to popular belief: all DVD players are required to decode video streams up to 9.8 Mbit/sec for indefinite periods of time. The popular average rate of 3.5 Mbit/sec or 4.7 Mbit/sec are merely canonical figures created by the notion that only single sided, single layer discs will hold feature length films. Should Single Sided, Double Layer discs prevail, the average rate would be almost twice as great. ALL DVD PLAYERS MUST SUSTAIN A 9.8 MBIT/SEC VIDEO DECODE RATE!!!!!!! Hardwired (Application Specific Integrated Circuits---ASICs) implementations of MPEG-2 MP@ML decoders are generally capable of handling 15 mbit/sec sustained rates."

2. "The maximum bitrate of 9.8 Mbit/sec is more restrictive than MP@ML's 15 Mbit/sec limit. However, the point of diminishing returns (no visual difference between original video and compressed video) is widely known to be around 9 Mbit/sec."

Just FYI.

[SaSi]

Both statements are correct and precice. However, I fail to understand how they relate to capturing.

Also, I think, the 9,8Mbps limit on DVDs has more to do with the rotation speed of the DVD disk and the transfer rate the DVD player can sustain, and is assuming that the DVD disk will be rotated at the "nominal" 1X speed.

[macm]

Both statements are correct and precice. However, I fail to understand how they relate to capturing.

It is simple. When capping realtime MPEG-2, if you want best quality go around 9000 bitrate. If size doesn't matters and you are satisfied with 1 hour per DVD, it will be OK.

As in the previous statement

The popular average rate of 3.5 Mbit/sec or 4.7 Mbit/sec are merely canonical figures created by the notion that only single sided, single layer discs will hold feature length films.

means that if you want poor quality and more video per DVD, go 3.5~4.7 Mbit/sec instead.

[BJ_M]

macm - those specifications are for pressed dvd's .... for burned dvds , it is a wise idea to not go to the max amount of bitrate , in fact 8000 - 8800 is fair max ..

also -- you can get extremly high quality at lower bitrates -- mostly it depends on the quality of your source ..

[macm]

Yes, I am aware of it!
But off all my tests it seems that as high as you go concerning bitrates you get high quality. Of course, there is a limit, and it seems 8500 a good shot. Actually, for burned dvd's going from 8000 to 9000 makes no difference at all, as you stated, it will depend on the source material.
But doing a realtime MPEG-2 capture, it really matters!!! Also GOP sequences play a role here: in fact, going I and P frames only also improves qiuality a lot. Inserting B frames improves compression but decreases quality...
So, all this is a matter of fine tunning and reading a lot of theory and experiment a lot.

[FOO]

Encoding in real time causes compromises that may make the
test invalid. Capturing uncompressed and encoding later
at half the bitrate might easily look as good as your 8000kbps.

[SLK001]

Well, why we're into facts, here's some more for you to digest. A DVD is read from a player at a constant rate of 26.16Mbps - that means "all the time". After demodulating the data, the resulting data stream is 13.08Mbps - again, "all the time". There is 2Mbps of error correction, and 1Mbps of navigational data, leaving 10.08Mbps of program data that is fed into the DVD player buffers - again, "all the time" (does the 10.08Mbps number look familiar?).

The 10.08Mbps consists of all your program elementry streams, of which up to 9.8Mbps can be video.

And, the rest is history...

[macm]

FOO,

I will test it tonight. I will do a MPEG2 cap @8500 and a AVI cap uncompressed then encode it with same MPEG2 settings in TMPGEnc Plus.
Let's see....

I'll let you know by tomorrow.

[FOO]

What encoder is being used for the real time encoding ?

[macm]

I use ATI MMC 8.7 and CATALYST 3.8.

[edthesped]

macm,

What were your results? I have experimented a little and believe that my capture card, AIW9800, is the limiting factor as I see no noticble difference between TV captured as MPEG or as AVI then converted to MPEG.

[macm]

edthesped,

actually there is no difference at all. Really.

I have experimented A LOT and here comes the bottomline:

if you have a decent source (VHS, TV signal etc) and your hardware is OK, then you go MPEG-2. Otherwise, if you need hard editing, go AVI then MPEG-2.

I never, ever had any synch problem. My dropped frames comes from some bad spot in source (deffective VHS, poor TV signal).
I usually capture rented VHS source, direct to MPEG-2, and I drop frames only when the tape has bad signal. But almost all tapes comes ok, and I cap 2 hours with 1 dropped frame

[adam]

macm I suggest you either find new legal sources to work with or find somewhere else to post. Capping rented VHS tapes for personal use is illegal.

Anyway, capping to avi and then converting to mpeg can increase quality quite a bit, but as others have said it depends on the quality of your source and hardware. For most users, I would suggest that they not cap directly to mpeg2 if quality is important.

[macm]

adam,

actually I am not capping "rented" tapes. I just bought a lot of tapes (~40) from an "out of bussiness" store (a video store, like Blockbusters). They went out of bussiness and sold everything... After transfering those to DVD, I just make them unusable and ....garbage!!

And, according to the Law, since I purchased it legally, with invoice and so, I can do whatever I want, for personal use only. I don't brake any copyright terms, since the only thing I am doing is a "material or media tranfer" (from "material VHS tape" to a "material DVD media") nad not duplicating anything to sell out. So, if I gave any wrong idea, I apologize, otherwise, you gotta be more polite and first ask what is all about, before judgement.

[BJ_M]

adam,

actually I am not capping "rented" tapes. I just bought a lot of tapes (~40) from an "out of bussiness" store (a video store, like Blockbusters). They went out of bussiness and sold everything... After transfering those to DVD, I just make them unusable and ....garbage!!

And, according to the Law, since I purchased it legally, with invoice and so, I can do whatever I want, for personal use only. I don't brake any copyright terms, since the only thing I am doing is a "material or media tranfer" (from "material VHS tape" to a "material DVD media") nad not duplicating anything to sell out. So, if I gave any wrong idea, I apologize, otherwise, you gotta be more polite and first ask what is all about, before judgement.

well you did say "...capture rented VHS source.." which i think anyone would think that in fact, you are 'capturing rented VHS source'...


most people would just say " capture from VHS" or "capture from used tapes" or at least "capture from previously rented VHS source" or to that effect --

I could see how adam could have easly "misinterpreted" your statement ..

[macm]

I see...

as I said, I am sorry. It was my fault, not clear enough.

But was he upset enough to invite me posting anywhere else???

We are here, in this community, to help each other, as "virtual fellows", if one of us becomes misunderstood or "misinterpreted" we deserve a friendly advice, not a judgement at first.

[lordsmurf]

I capture a lot of "rentals" too. Same situation... places like Blockbuster and other companies that sell off old tapes for as low as 75 cents per tape sometimes.

We use the word "rental" too because it implies the hell the tape has seen and that it is far-degraded source most times. "Pre-owned" or "former rentals" may be better here. Glad I didn't make that mistake and get jumped on.

I face the same problems. The tape will drop no matter what magic you try. It's the source.

[adam]

I did not jump on anyone, I simply stated that if his sources were not legal he should not post here. The rules of this board say no less. Why do you assume that because I gave you a verbal warning I must therefore be upset? In case you hadn't noticed, as a moderator one of my jobs is to make judgments regarding people's posts, make informed decisions, and issue warnings when necessary. I did exactly that.

I can't think of why anyone would refer to a used VHS that they purchased as "rented," without giving at least some explanation as to why they chose to use those words. Saying that you "capture rented VHS" seems to pretty clearly imply that you rented it. If it walks like a duck and quacks then don't blame me for putting two and two together. Either say what you mean and mean what you say or don't complain when people misunderstand you.

[Nelson37]

MACM - Adam did just what he is supposed to do when someone clearly implies an illegal act, as you did. Mistakes and upset does not enter into it, he policed a violation of the rules of this site.

Now that both have clarified the situation, perhaps the term "purchased rentals" or something similar should be used to avoid further confusion.

Now, for real-time captures, I'm still not sure what the original point was, but IMO the storage capacity of DVD virtually eliminates the need to re-encode. I typically use MPEG-2, Avg VBR in the 3-5000 range with real-time IVTC, yielding around 4 hours per DVD. AVI caps re-encoded w/CCE to similar specs look only very slightly better, or the same, for a lot more effort. Higher bitrates in either case do not seem to give much improvement for my source.

I should point out that I quoted above the specified bitrate, and ATI MMC often yields significantly different rates.

[lordsmurf]

If it walks like a duck and quacks then don't blame me for putting two and two together. Either say what you mean and mean what you say or don't complain when people misunderstand you.

Quack quack. Quack. Quack.

Calm down man. We hear you. You seem awful stressed.

[adam]

I actually am under some stress from school, but that doesn't reflect on anything I post in this forum. I am perfectly calm, and am just doing my job as a moderator. I don't see anything in that part of my post that you quoted which would suggest otherwise.

I feel like Adam Sandler in Anger Management.

"Calm down sir."
"But I just asked for a pillow"
"Calm down sir"

[Thorn]

lol@adam - learn to keep your temper

Seriously people, if you imply you're doing illegal things don't get upset when people call you on it. No one has been punished for an honest slip-up on this board - you get the chance to explain.

Capping is all about what balance of difficulty and quality you can put up with. Excluding top-end harware encoders, you'll always get better quality capturing to lossless avi and then converting to mpeg.

However, 90% of users today are more concerned with ease of use and inexpensive equipment. The quality loss for direct-to-mpeg capture is often small enough for those who aren't top-quality-at-all-costs crusaders. Everyone has a different threshold as to what compromises they'll make.

As for your bitrate, I've never seen 3.5 or 4.7 cited, but 4Mbps-6Mbps are popular for DVDR because anything above 8Mbps is asking for trouble on crappy media and/or crappy DVD players.