I Just Don't Get it ???? ;)

[DJRumpy]

I wonder why TMPGenc doesn't come with an ultra-low bitrate matix like CCE does. I also wonder if the same matrix setting in TMPGEnc would produce as good a quality as CCE. The ultra-low bitrate matrix looks like this:

Intra:
8 16 19 22 99 99 99 99
16 16 22 24 99 99 99 99
19 22 26 27 99 99 99 99
22 22 26 27 99 99 99 99
22 26 27 29 99 99 99 99
26 27 29 32 99 99 99 99
26 27 29 34 99 99 99 99
27 29 35 38 99 99 99 99

Non Intra:
16 17 18 19 99 99 99 99
17 18 19 20 99 99 99 99
18 19 20 21 99 99 99 99
19 20 21 22 99 99 99 99
20 21 22 23 99 99 99 99
21 22 23 24 99 99 99 99
22 23 24 26 99 99 99 99
23 24 25 27 99 99 99 99

Anyone want to test? I don't have the patience... tuckin:

[SaSi]

Does anyone have a good explanation as to how the Quantization Matrix is used? How the values affect encoding?

Have found nothing relevant and in my third reading (now) of the MPEG-2 standard, I can only guess that these values are used as weights for the calculation and truncation of pixel information for each macroblock. I also guess that higher values in the Q.M. force pixels to be ignored "more". Is this correct?

Any MPEG-2 gurus around?

[hustbaer]

@SaSi: hi!

well, it's pretty hard to explain (at least for me).
technically, the quantizer-matrix is used to quantize the DCT transformed macro-blocks - by dividing the macro-block by the quantizer-matrix and rounding the result to the nearest integer.

the result of a DCT is a matrix that has all low-frequenzy information in the upper left part of the matrix, and all high frequenzy information in the right, bottom, and right-bottom parts.
the fine vertical detail is in bottom 1/2 of the matrix, and the fine horizontal detail is in right 1/2 of the matrix.

so the numbers in the top-left quadrant of the quantizer matrix tell the encoder how much the low-frequenzy (low-detail) information shall be quantized (or "cut" if you prefer the term), the values on the right tell the encoder how much fine horizontal detail shall be quantized.
the higher the number, the more quantization will be applied, the more information will be lost.

if bitrate is short, you should try higher numbers in the bottom-right region.

although it's not that easy to make good matrizes.
if you make all rows in the rightmost 2 columns 99 and leave the rest unaltered, you will lose much detail and gain nearly nothing in concerns of bitrate or overall video-quality in heavy movement scenes.

the reason for this is the way the data is finally compressed, but it's a little "too hard to explain" a topic for me...

so to give you a direct answer... higher values force frequenzies to be compresse more, not pixels

i hope this helps a little,
bye,
--hustbaer

[DJRumpy]

EnNiS, why in the world would you want to place a movie on a single CD-R? The quality is horrible, in any light. I like the anology from another thread. It's like watching TV through a coke bottle. If you want to scare someone away from doing their own encodes, let them try it the normal way first.

<begin pulpit speech>
Don't be so cheap. CD-R's cost pennies. Is the second trip to the dvd player in 40-60 minutes really going to kill you? You probaby get up more than that to snack, get something to drink, or to just go to the bathroom.

Of course, if it bothers you that much, you could buy a DVD -R/+R player, so you won't have to eek out every tiny bit of value in a CD-R which you can buy by the hundreds.
<end pulpit speech>

Don't take this the wrong way, as it's not an attack on you. Your kind enough to take your time, and offer advice in a forum, which is how things should be. Rather, it's an attack on the 1 VCD movie method. It's a poor mans VCR, as even a VCR tape will look superior.

hustbaer, these are the matricies from Cinema Craft. They do produce excellent quality (when you don't try to throw an entire movie on to VCD anyway). You should give them a try.

[Conquest10]

actually, you can get pretty damn good results out of a single disc encode. its not dvd, but its still good using kwag's templates.

[ZippyP.]

DJRumpy, re pulpit speech:

Amen!

[EnNiS]

DJRumpy
first of u can get fuckin good quality
all depends on length of film
if it is below 90 min it will look great with the settings i encluded above
if it is above 90 min i divide it into 2 and so i get fuckin kick ass quality, i get teh most out of the vcd/cdr
this is what u guys should do instead of making a vcd
i should make a guide lol
[/b]for those who just do normally vcd's and cut them in half
instead of making a normal vcd with a bitrate or 1150, how bout make it like 2000
say ur movie is 90 minutes
and u encode audio at 224 and video at 1150, u will get a size of 910 mb
that sbullshit because if u already are going to divide it to 2 cd's, why not make each cd 800 mb (the maximum) versus 455 mb?
u can way way better quality
use the bitrate calc: https://www.videohelp.com/calc.htm
and find hte max bitrate (just a tip for beter quality, cut out the credits using sourcerange in tmpg)
so now instead of having 224 audio, 1150 video, size 910, u can make it
around 2259
humm, whats better quality
im out
peace

[DJRumpy]

EnNiS, I have an HDTV. VCD looks bad no matter what you do with it. The vertical resolution is too low. I have yet to see a decent quality VCD of any length on one CD. I haven't seen one of yours yet. You never know, but I remain doubtful. I have a DVD burner, so the format has no interest for me. Onto the reason for my post...

You should at least warn them when posting this info, that what your talking about is a non-compliant VCD (xVCD), meaning most will not be able to play what your proposing.

for those who just do normally vcd's and cut them in half
instead of making a normal vcd with a bitrate or 1150, how bout make it like 2000

They cut them this way, because the VCD standard specifies a max bitrate of 1150 Kb/s, and audio at 224Kb/s. This bitrate looks poor, even at VCD resolutions, hence the reason for CVD, SVCD, and DVD. They are designed for higher bitrates and resolutions. I'm guessing your player doesn't support CVD/SVCD?

What your propsoing an xVCD. Although your player may play it, a newbie entering here, would spend hours converting a movie, faithfully following your instructions, and ending up with a coaster.

As for VCD itself, the vertical resolution on VCD is just too low. It looks soft, even on store bought VCD. CVD looks fine though (480 Vertical). I often cut this type for friends/family, although only a small percentage of players support CVD/SVCD (I bought my famlily their DVD players with this format in mind).

You should definately create a guide for xVCD though, as some might have interest in what your doing.

[vitualis]

Example 3:
(a) VBR @ 1000 / 2000 / 3000 kbps vs.
(b) VBR @ 2000 / 2000 / 3000 kbps
Result: file (b) is larger than file (a)
Reason: ((1000+2000+3000)/3)=2000; ((2000+2000+3000)/3)=2333.

Just in case someone missed the discussion up this thread, the average bitrate is what determines the final filesize. (a) and (b) will have the same filesize more or less.

Most encoders will be a "little" bit off in terms of the actual bitrate for VBR but not to a huge amount.

Once again, if you set the min-avg-max, it is the AVERAGE bitrate that will control your size.

In a perfect encoder, the min-bitrate should always be ZERO and the max bitrate should always be the max. allowable for your medium (i.e., for SVCD at about 2500 kbit/s for video). The reasons for setting a minimum bitrate other than zero include:
(1) reader problems with handling very low bitrates and
(2) the MPEG encoder is not perfect and incorrectly allocates insufficient bits to some scenes.

Regards.

[DJRumpy]

I caught it. It was actually a point of debate. Average sets output size..in case 2, and 3. They would be the same (give or take a byte or 3).

[EnNiS]

sorry, i was away i couldnt post a reply
yeh sure i can make a guide
but the majority of dvd players thgat supoort vcd support xvcd
i haev 2 dvd players, one for my room (apex ad1500 (supports everything)) and a toshiba sdv280 (plays everything but svcd, xsvcd, and cvd) i would rather burn a decent quality vcd and have it play of 95% of the players i try it in (ie. friends houses) than have a kick ass quality svcd, which is 2-3 cd's, and haev it only play on 40% of my friends dvds
my room tv which my apex is hoooked up to is only 20 inch, so it looks fine
and all my friends tv's they look fine to, they vary from 30-40 inch
so i am sticking with xvcd
thanx
cya

[DJRumpy]

If you search through the players section, you'll find that most do not support xVCD. I would almost go so far as to say more seem to support SVCD, than xVCD, but I certainly didn't scan through more than a page or two of players.

I wonder if one of the moderators has the numbers in a db (Baldrick, Adam, Craig...someone?), which could quickly spit out the current percentages of players supporting which formats? It would be interesting to see what the trend is. It does seem that most newer players at least support SVCD. I'm guessing the home video hobby is forcing venders to include compatability if they want to compete in the market.

[EddyH]

Single disc xVCD does me just fine on my 14" TV and cheap S/VCD/DVD standalone (~2600k max). Just set a likely CQ level and a 2400k cap (~50k minimum), tweak a few filters if needed, max the motion search, and let it fly; do a second pass tweaked up or down if necessary, still quicker than 2pass VBR. Get very good results and low average Q's (usually much below equivalent CBR), and all on the one easy, convenient CDR. You may say about getting up to change the disc being a small thing; who here got the flipdisc version of Jackie Brown on early DVD and was pissed off by it? More than anything, it breaks up the flow of a film - this is why intervals are rare in cinemas any more. A matter of principle if nothing else (and CDRs aren't that cheap to me, as a student. each one is still a good 2.5 to 4 packets of noodles, especially if i buy a brand that will actually stay readable more than 6 months (glares at memorex)).

I just hope that when I have the now-huge amount of fundage required a large hi-def TV, I won't still be stingy enough to be burning VCDs instead of buying the DVDs
Mind you I intend getting a DVDR before I get a HDTV (well in the UK it'll be a mere plasma or large progressive for now, til someone even thinks of introducing HD here)..

[vitualis]

Since an XVCD is simply an off-spec VCD, it really depends on "how" off-spec you go in terms of its compatibility.

For example, if you make it trivially off spec by using (for example) a slightly lower bitrate, it will work on almost all players.

However, if you use an extremely high bitrate and large framesize, etc., then it will work on very few players.

As such, it is very difficult to have any meaningful quantification of XVCD-compatibility.

Regards.

[TwIZzlEr]

My (1movie/1cd) xvcd's in cq are better than video tapes. Plus they'll last a $][17load lot longer than VHS. Yeah, yeah, I got a DVD burner, which is good, but my xvcd's on my 53" look great too. I remember back in the day when watching tapes, there would always be specs all over the place while viewing them. xvcd... NONE.