CVD,I don't get it.

[wulf109]

I've been looking at posts about CVD format. The posts seem to say it's better than SVCD? The suggested templates seem to be SVCD with the change being making the resolution 352 x 480.
What am I missing?

[Donny661]

You can read all about CVD here http://forum.vcdhelp.com/userguides/98177.php

This should be the answer to your curiosity

[adam]

For all intents and purposes CVD is just a SVCD but with 352x480/576 resolution (half D1.) CVD is a standardized format with specific hardware support, but I'm not sure if that standard applies outside of china, unlike with SVCD.

There is actually another format which you probably haven't heard of either. Its called HQ_VCD and is also very similar to SVCD. All three of these formats; HQ_VCD, CVD, and SVCD were popular in China and were being considered for worldwide standardization. SVCD won out and thats why its better known outside of China. In China all SVCD compatible dvd players are required by law to play HQ_VCD, CVD, and VCD as well. Outside of China I suppose its not an actual requirement but for the most part it seems to be the case anyway. 352x480 is a compliant dvd resolution so it seems that any dvd player should be able to display this correctly. This doesnt necessarily have to apply to CVDS but like I said, that seems to be the case. I've yet to find a svcd compatible dvd player which cant also play CVDS.

CVD is not necessarily any better than SVCD. They each have their respective advantages and disadvantages. SVCD is probably more compatible on more dvd players but CVD uses a dvd compliant resolution so it can be transferred to dvd later without having to transcode it again.

As far as quality differences, its give and take. Since CVD has a smaller resolution you get more bits per pixel so you get less artifacts and preserve more of the original quality of the source. In my opinion CVD resolution (half D1) is a much more reasonable res to use at bitrates under 3mbits. If you just think about it, its literally got half as many pixels as dvd does. A typical dvd probably uses an avg bitrate of between 5 and 6mbits. So at 352x480/576 @2.6mbits your compliant CVD literally has close to the same amount of bits per pixel as the source dvd does. With SVCD this is not possible. Technically speaking, CVD probably DOES do a better job of preserving the source dvd's original quality.

However, since the resolution is smaller your picture is not as sharp and you do lose some detail. Some people prefer higher resolution to more bits per pixel. Its all highly subjective.

It should be noted that 352x480 at 2mbits is considered one of mpeg's sweet spots. At this combination mpeg is considered to have the optimum balance between resolution and bits per pixel. My own personal philosophy is that if my movie is short enough that I can achieve an avg bitrate higher than 2mbits, then I go with SVCD. Otherwise I stick to CVD.

[wulf109]

I certainly agree with your comments about CVD. I encoded the movie Soldier at 352 x 480 and it looks much bettter than 352 x240 and is absent the macroblocking I see at 720 x 480. I've been making VCD's at 720 x 480 with de-interlacing filter at double. VCD at 2250bits seeems to look better than SVCD at 720 x 480. Your comments most welcome. By the way I'm not frame-serving.

[adam]

By the way I'm not frame-serving.

Haha, great one. Well I encourage you to continue using whichever methods work best for you and as always good luck.

[wulf109]

I was hoping you would address the question about 720 x 480,VCD v\s SVCD.

[adam]

First off if you want to compare mpeg1 and mpeg2 ensure that all of your settings are equal. Make sure the XSVCD has a dc of 8 since thats all that mpeg1 supports. At low bitrates (ex: 3Mbits and under) a higher dc will actually result in lower quality.

Well theoretically unless you use a very high bitrate or are using interlaced output then mpeg1 and mpeg2 should look identical at the same settings. In reality, when you throw an encoder into the mix, and an arguably incosistent encoder at that, anything can happen. Of course when I say this I am assuming you're using TMPGenc. The best answer I can give you is that TMPGenc's mpeg1 encoding algorthms are optimized for low bitrates and its mpeg2 encoding algorthms are optimized for high bitrates. At 720x480 and ~2mbits your bitrate is actually very low since the picture size is so large. Still, the quality difference should have been very slight. I'm suprised you were able to notice a difference, your eyes must be better than mine.

Now if you wanted to fully use mpeg2's benefits you would have left the XSVCD interlaced. This is the main benefit of mpeg2 over mpeg1 and the real reason it was even created in the first place. Deinterlacing should only be used as a last resort since it always lowers quality. If you had left the film interlaced the XSVCD probably would have looked better than the XVCD.