How do they fit an entire DivX movie on 1 / 2 CD(s)?

[ionutvasilescu]

Hi all! I've done some video conversions by now, after reading as much as possible (mostly on www.videohelp.com and www.100fps.com). My problem is about the max. size of the video (at an acceptable quality) that can fit on a CD.
I use Scenalyzer Live for capturing and then VirtualDub for compressing the captured video.
My best result consists in a 45-50 min. avi file on a CD (video compression - 1 pass - using DivX 5.2.1 and audio compression using Lame MP3 codec); the resolution is 640x480. I usually use Smart Deinterlacer filter, Resize filter, etc.
What I can't understand is how can a 1.30-2.00 hour movie fit on a CD??; the world is full of DivX movies on CDs (still much cheaper than the DVDs). A DivX movie is made to fit on ONE or TWO CDs (longer movies are on three CDs...never mind). And the quality is still very high. How could I make longer videos fit on a CD (without important loss in quality)?? I mean...it seems impossible with all these common tools that we (you) all use.

Thank you very much, and hope to hear some pro answers!!!

[bazooka]

Convert to videocd

You can put 80 minutes of video and audio on a cd.

[booaf]

How could I make longer videos fit on a CD (without important loss in quality)??

Go to www.kvcd.net and check out their cqmatic tool.
It's optimal for CQ encoding with TMPGEnc.

Greetings,
Baf

[koorosh]

My best result consists in a 45-50 min. avi file on a CD (video compression - 1 pass - using DivX 5.2.1 and audio compression using Lame MP3 codec); the resolution is 640x480.

what is your encoding bitrate with divx ?
lower the bitrate to fit more data.

[jimmalenko]

I daresay that most DivX movies that are similar to the ones you're talking about use multipass VBR as well as VBR audio. Maybe you could look at doing two or three passes and dropping your bitrate for both video and audio. That should allow you to fit more on a CD.

[celtic_druid]

They are also mostly XviD and not DivX, they are also mostly widescreen, so less pixels.

[animatron]

They are also mostly XviD and not DivX, they are also mostly widescreen, so less pixels.

Also XviD and DivX "Cheat", because you don't need to encode black borders as in MPEG1 and MPEG2 to keep correct aspect.
And black bars cost a lot of precious bits!

[celtic_druid]

As long as they are mod16, black borders don't cost much at all. Besides if you have a player that supports RAW mpg's then you could use MPEG1/2 without black bars.

[animatron]

As long as they are mod16, black borders don't cost much at all.

They do cost. Encode something with and then without bars, and you'll see quite a difference. Even if you mask them completely black before encoding.

Besides if you have a player that supports RAW mpg's then you could use MPEG1/2 without black bars.

I wish!, but I have a Philips player capable of playing DivX, and I've already tried that. It doesn't work
I still have to encode all mpeg videos as 4:3 or 16:9 with the black bars. If not, it stretches the movie and looks like hell!

[manono]

They do cost.

No they don't, if added by mod16. Perhaps for your tests you didn't add on black by multiples of 16. We're talking single digit percentages here. Be real sure before taking on the Druid. He knows whereof he speaks.

[celtic_druid]

I never said that they didn't cost anyway. Just that they don't hurt that much. If the border falls in the middle of a macroblock then it will hurt compressability quite badly.

Anyone who is really interested is welcome to run some fixed quant tests.

[Joex444]

The encodes that can fit 90 minutes on a disc, or even 2 hours, are not done at 640x480. They usually are 2.35:1 movies to start with, not 4:3, and get a resolution that is lower. Perhaps 640x272, or even lower, such as 592x320 (16:9) or 592x256 (2.35:1). So, even at the 'higher' 640x272 resolution, it has 56% of the pixels, right off the bat, so, with whatever settings you have now, you could fit 90 minutes on 1 CD with them NOW, if you had widescreen material (50 min now * 480 res now / 272 res widescreen = 88 min; 640 is not a factor because it is common to both, only the vertical is changing, and the area is changing at the same rate as the vertical, since the horizontal is constant).

So, if you try 512x384 (196kpixels) instead of 640x480 (307kpixels), you should get an improvement in the capacity (minutes wise) of the disc. Theoretically it should be enough so that if you are now fitting 50 min, you would fit 79 min.

Now, the other thing, is you should be able to drop your bitrate by a good amount if you use 2 passes. I'd say 30%, but that's just from my experience, maybe more depending on the material.

I'd also give XviD a go. With VirtualDub usage, it is much more bit-accurate...meaning, that it will more accurately encode to the given kbps, or it will fit it to a certain size in kb (ie, encode audio, then take size of cd in kb, subtract kb of the audio, and that is what to put there for the output size of the file).

Whatever you do, don't encode it to videocd. Sure, you get 80 minutes and might be able to play it on the TV. Check out the specs of it though. 352x240, MPEG-1 1150kbps. MPEG-1 sucks as an algorithm to start with, even with KVCD matrices it's not as good as divx/xvid (tho markedly better than VideoCD). I'd combine the KVCD matrix and SVCD specs if I were going to go the route of "let's put it on a CD that will play in my DVD player," because its MPEG-2, the matrix helps save bits quite well, the max bitrate is increased to 2520kbps, the resolution is increased to 480x480 (sounds weird, during playback it is horizontally stretched to 640x480, thus making 480x480 a 4:3 resolution [with the 4:3 flag; if you put a 16:9 flag, it would either ignore it or make things look weird]).

Also, since it seems you are capturing things, if your capture card/device only supports MONO audio, then only encode the audio as 1 channel. This can save you 50% compared to stereo where stereo offers *NO* advantage. So, 128kbps MP3 Stereo would turn into 64kbps MP3 Mono, same samping rate. I don't believe that you should lower the quality of the audio to increase quality for the video. What you seem to have is good quality video that you want to make smaller to fit more of it on the CD. Once you get 90 minutes on a CD, though, your 128kbps stereo file is taking up as much space as a 256kbps stereo file if it were 45 minutes. You certainly wouldn't use 256kbps, would you? So, if it is mono, use mono, then you're taking up as much space on the disc. Also try VBR audio, if mono, a range of like 24kbps to 96kbps would be good; stereo just double 'em, so, 48-192. You can also try ABR if VBR is getting bigger than the CBR encoding you probably use now. ABR is like VBR, except ABR is Average Bitrate, so, you can specify a range of, say, 48-192kbps, but then also say that you want it to come out to an average of 105kbps, so, it would be as big as a CBR with 105kbps (which, I do think you can make, I was fooling around with lame before, and was able to do things like that....or was it the AAC encoder, maybe both!).

Anyways, that's enough, should help you out quite a bit.

Basically, lower the resolution to 512x384, and change to multipass video encoding (also should try Xvid, with the highest settings if possible -- i use mode precision:6; vhq: 1; turbo on; chroma on.), and use mono audio if your capture device is only capable of mono, or if you are usign a VCR that only has mono, or if you are using a stereo capture device with stereo VCR and mono tape.

[animatron]

No they don't

Yes they DO!
http://64.233.161.104/search?q=cache:t89WOR9Jq0cJ:www.kvcd.net/forum/viewtopic.php%3Ft%3D4439+avisynth+kvcd+black+borders+sh0dan&hl=en&client=firefox-a
Read sh0dan's comments there, the developer of AviSynth.
Posted from Google's cache, because you can't see the original link, unless you log on KVCD's forum.

[ionutvasilescu]

Bazooka wrote:
"Convert to videocd"

Wel...videoCDs are 320x240 - so the resolution is to low. I want a full screen acceptable quality.

Joex444 - you have been most helpful. Thank you very much. Now I'm experimenting the XVid compression. I still have very much to find out about all the parameters of Xvid and how to scale them better.

[jimmalenko]

VCDs are 320x240

352x240 actually