DivX to SVCD - Quality issues

[CU]

I like to convert my DivX movies to SVCD's so that I can watch them on my TV using my DVD player. I used to convert them to 3 x SVCD's, using CBR of 2500kbits/sec and high quality motion detection, then burning them to CD-RW to watch them. Recently though, I've started burning them to normal CD's so I can watch them again without reconverting again. However, burning to 3 CD's could get expensive, so I've been converting to 2 x SVCD's using 2-pass VBR.

With short movies, this isn't a problem, as I can maintain an average bitrate of 2200kbits/sec and above over 2 CD's. However, with longer movies, I can only store about 45 mins per CD before the quality becomes really poor, below 1800kbits/sec. However, I've seen rips that store 60mins per CD with quality that looks better than some of my 2500kbits/sec encodes, and yet I have no idea how to achieve that. Could anyone offer any help / advice?

[Baldrick]

You can't compare divx to svcd with dvd to svcd(svcd dvd rips). Better source means that you will get better svcd cause a divx is already very compressed and lots of video information is gone that are VERY useful when encoding video. You could try use CCE with several passes but I don't think it will help that much when your source is DivX.

[EddyH]

3 CDRs (per movie) could be expensive?

Where the heck do you live? Up a mountain in the himalayas?

Last time I checked 3CDs = $2.00 even if you shop at a really expensive store. Hardly breaking the bank compared to the cost of the actual DVD or even a VHS cassette to bootleg it on. Where I buy mine it's £1.20 for three worked out (of a 3.99 10-pack) and it's even cheaper online. 18 cents a disc some places.

Or is it that you simply have a huge amount of videos, in which case your main concern should really be the 'missing' hard disk space and the weeks of cpu time / work you'll need to svcd it all.


As for your little problem, all i can say is, either an encoder bug, or your standards are set far too high - especially for svcd from divx! as decent quality can often be got out of plain xvcd on a single disc (though of course 2-disc still far superior) it's odd that a 2 or 3 SVCDs set aren't floating your boat..

[CU]

Actually, I live in South Africa, ALMOST as bad as the Himalayas

I was merely curious though. I understand the fact that you'll get a better quality SVCD from a DVD as opposed to a DivX, but I was just curious how people managed to fit 60 minutes of high quality footage onto one CD at what is obviously a very decent bitrate.

[mats.hogberg]

60 min on an 80 min CD gives you an average video bitrate around 1590 kbps, provided 224 kbps audio. No clever tricks in the world can change that. However, multi pass VBR might turn out better than CBR. Besides that, only source material matters!

/Mats

[LeeBear]

If you're not getting good quality putting 60 minutes of film onto a SVCD then there are many things you can do to improve what you are getting. Here's some suggestions:

-increase the number of passes, 3-pass will improve your quality a bit, some even use 4 but the gains start to become minimal
-if sound isn't that important to you, you can lower the audio bitrate down to 160 or 192 and gain some extra bits for the video
-I don't know what TV systems they have down in South Africa but if it's NTSC system then make sure you're encoding at 23.976 fps then use a 3:2 pulldown to change the framerate to 29.97, this will give you about 20% more bits per frame then encoding directly to 29.97 fps
-lastly and often overlooked is the use of filters. I suggest using the excellent Convulation 3D, and MSharp filter that's available for AVISynth. This will make the movie easier to compress for the encoder giving you much better quality in the end.

Give those a try.

-LeeBear

[CU]

Thanks, I'll give those a try and see what happens.

[banjazzer]

Here are some more suggestions:

Use 2-pass VBR with max bitrate=2496 and min bitrate=1200.

Use CQ mode with same max and min but quality setting between 75 and 85. (Note: you will have to encode a few samples to predict final filesize, but the whole process will take half the time).

Use CCE 3-pass VBR. (Fastest, arguably highest quality, and potentially most expensive solution).

[guitar_george_skank]

Get yourself a copy of FitCD as well. You can open the divX file in this and it will show you the exact crop and resize options to use to get the best quality. I take TV overscan blocks (no more than 2) into account as well which means I get a better compression ratio in FitCD. Keeping a compression ratio of 1:36 or under will pretty much give you great results every time as long as your source is good as well. I couldn't get by without FitCD now.

Some examples: Keeping to a ratio of 1:36 approx. in FitCD using 2 overscan blocks.

Assuming 192 audio and PAL DVD source.

Full screen: SVCD - 34mins, CVD - 49mins
16:9: SVCD - 41mins, CVD - 63mins
2.11:1 SVCD - 55mins, CVD - 74mins!!

DivX files are good for this kind of thing. I can get 92mins on 1 CD using CVD and 2 overscan blocks from a 640x272 divx file. Of course quality is very subjective and I suggest you try a few tests first although I stand by my results. Because you reduce the size of the actual film pixels there are less pixels for the given bitrate to work with so therefore a better picture. Most TV's can't show upto about 16 pixels all around the edge of the screen so why waste bits on those pixels? It works for me anyway, but others might not agree. In the end as long as your happy with the result that's all you can ask for.

Good luck,

GGS.

PS has anyone tried the donation version Fit2Disc? I tried to make a donation but didn't really trust the system used, but that was the only way the author would accept a donation outside of Germany. Youir opinions would be interesting.