Best CDR for video

[kwmarriott]

@ flying dutchman. So: just what is the maximum size of an an mpeg 2 file that will fit on a 650 (74 minute) or 700 (80 minute) cdr? I am surprised that you fitted an 820 mb file on as I have been keeping my mpeg 2 renders to below 700mb. I guess I could increase the bitrate if I'm being too conservative.

Been an interesting thread this one!

In reply to one of the posts about DVD writing: I just wonder much disc space and time it would take to capture and prepare files for writing to DVD-I can't imagine letting tmpgenc render 4gb worth of video!

I would think it would be time for hardware capture straight to mpeg2.

[Flying dutchman]

Theoretically, if you really push it to the limits:

74 min CDR =650 mb x 2324/2048 = 737 mb
80 min CDR =700 mb x 2324/2048 = 794 mb
90 min CDR =800 mb x 2324/2048 = 907 mb
99 min CDR =870 mb x 2324/2048 = 987 mb

(where 1mb=1024x1024 bytes)

I would always subtract 2 mb to be on the safe side. The VCD/SVCD application files also take up some space.

On a 74 min CDR you can obtain roughly the following playing times at a constant (or average) bitrate (assuming you leave your audio to 224 kbps):

37 min=2500 kbps
40 min=2255
45 min=1979
50 min=1759
55 min=1579
60 min=1429
65 min=1300
70 min=1192
73 min=1150

[kwmarriott]

@ flying dutchman. Are the times for vcd (mpeg1) or svcd (mepg 2) oops-just answered that, you can't have those data rates on VCD!

[Flying dutchman]

One more thing, for SVCD I would recommend to mask the outer 16 pixels of your clip in black (top,bottom,left and right).

This falls in the so-called overscan area and is thus invisible anyway on your TV. This way, the Mpeg encoder has 10% more effective bandwidth for the visible part. You can either improve the visual quality or stretch your playing time a bit...

[Brian Ellis]

FD

I think that it may have checksum correction but maybe not redundancy correction, like audio CDs.

David

There are probably small differences in quality, but I don't think there is anything to get paranoid about. Any reasonable branded make should be OK, but beware of unbranded ones, including those with the name of the shop.

I think there are more likely to be problems with CD drives than CD discs, as I explained above. After all, if you consider the precision with which that spot of light must be focussed on one minute data bit, it is easy to imagine that the mechanical tolerances must be very tight, even with negative feedback in the servo system. We are in the realms of a micrometre or 0.04 thousandths of an inch.

Zeb7

Yes, you understood me correctly: I think that it could well be that the density of active photoinitiators would decay exponentially with time. You can consider that it's like a "half-life" (not strictly true as scientifically it would be described as a folded-e lifetime ie the time for the density to decay to 1/e or 0.3679 of the original). If there are, say, 10,000 per unit volume to start with, there would be 3,679 after one unit lifetime, 1,353 after two units, 498 after three and so on. The initial quantity would be dosed so that there would still be sufficient for it work correctly at the end of the shelf life. However, the important point is that this decay will tend towards zero but never reach it (called asymptotic to zero), so that there will always be a possibility that some carbon may be liberated under unsuitable conditions but, the longer the time, the less likely that an error could be caused. Assuming my hypothesis is correct.

[zeb7]

Thanks Brian ,
I've also been checking CD's with the CDR Identifier program
and using this link to track the factory to the brand name
http://www.cdmediaworld.com/hardware...actories.shtml

Here's some more links for anyone who wants
to read more info on CD and DVD
http://www.disctronics.co.uk/technol.../cd_frames.htm
and
http://www.discusa.com/cdref/cdbasics/cdbasics7.htm

Truths About Colors
http://www.cd-recordable.com/truths.html

------
SVCD Audio, (should we start a new thead ?)

My source Audio isn't very high quality so i
never encode the Audio at 224kbs on SVCD's, my settings would General be 80kbs mono and 160 to 192 for Stereo.

Ideally VBR audio would be preferred but the "tolame.exe" mpeg1/2 VBR dos encoder
is not of sufficient quality to be worth the trouble setting up (as you need to run it separately the encode VBR)

[Flying dutchman]

... But stereo is a MUST according to the SVCD specs.

I personally use joint-stereo at 128 kbps. Joint-stereo has the advantage that the stereo signal is subdivided into two components consisting of the "sum" and the "difference" of the two audio channels. This trick is very old, by the way, it is also used by analog FM-stereo radio stations.

The "sum" component (= the "mono" component) needs much more bitrate than the "difference" (="stereo") component because, typically, the left- and right sound channel aren't too different. This way, you get better audio quality than by simply assigning 50% of the bitrate to the left- and 50% to the right channel as is the case in "normal" stereo.


(Of course, the DVD player performs the opposite action and reconstructs the two channels again.)

[zeb7]

mono is with the SVCD specs , i will try to attach the info i use to this post.

> I personally use joint-stereo at 128 kbps.
Good point ,J-stereo slipped my mind for a moment ( i forgot about it )
I must add for any one encoding very high quality that J-stereo does have problems
with some music and Dolby stereo with would need to be encoded at 224kbs > 384kbs Stereo mode

As a simple guide to their use ;
mono __64kbs to 128kbs
J-stereo _____80kbs to 224kbs
Stereo ________128kbs to 384kbs

[zeb7]

And this file shows all the SVCD Audio mode's

[Flying dutchman]

Here's an interesting link about "enlarging" your CDROM's by writing without error correction:

http://www.doom9.org/xcd.htm

[Flying dutchman]

Zeb 7:

As far as I know, not every mpeg-1 level 2 audio format in your list is allowed in VCD and SVCD.

<QUOTE> (from http://www.uwasa.fi/~f76998/video/svcd/overview/) :

"In terms of video and audio quality, SVCD is in between VCD 2.0 and DVD, using a 2x CD drive to support variable bitrate (VBR) MPEG-2 video up to 2.6 Mbps, and either 1 or 2 MPEG-2 Layer II stereo audio streams (for soundtracks in two different languages). It is also possible to use MPEG-2 Multi-Channel 5.1 surround audio encoding."

</QUOTE>

So if I take this literally, stereo IS a requirement for SVCD.
I am pretty sure it is for VCD, too: I remember problems I had in the past with the panasonic encoder (or was it LSX?), where it simply refused to encode VCD's from mono audio material.

BTW, here's an interesting link for making multichannel audio on SVCD:

http://www.stud.uni-siegen.de/sven.koelsch/mpeg2mc/

[zeb7]

that websight seem's a little restrictive with the SVCD audio , however i'll try and find
the link to the .PDF svcd doc phillips released.
i'm 90% sure mono was included in it.

Trouble is all these DVD players expect anything ,

I am going to try J-stereo with TMPGEnc next time i do a SVCD , thanks