I got to know, What Codec do I use...

[Joe Sloppy]

Ok, After doing a company demo cd and encoding all the video to MPEG 4 v2 (it just seemed to compress better), I get a letter from the company's consultant saying that the video should be more "user friendly" without having the user to install additional software to view the demo. The thing was, he was testing it on Win98 and I guess he didn't have MPEG4-v2 although I had the demo check and inform the user to click yes to install the codec in order for the video to play. Well, now I am stuck. I don’t know what to do, I have about 20 videos, each about 1 minute long that need re-encoding but I am not even sure which codec to use. What’s the standard windows codec that’s on win95, 98, 2000, etc...

Suggestions please???

[eric_darling]

Re: I got to know, What Codec do I use...

MPEG-1

[Joe Sloppy]

Re: I got to know, What Codec do I use...

Thanks, I have been testing using TMPGEnc and it works great.

Ok, so if I use mpeg 1, what bitrate is recommended? Is over 1500 ok? Can I use VBR, I see the option available for Mpeg-1, or is CBR more computer friendly? Just trying to get it right the second time around.

[eric_darling]

Re: I got to know, What Codec do I use...

Stick with CBR for the slower processors out there. VBR vs. CBR is really a processor related question, so if you know you're limited to newer computers in your distribution, then go for VBR. Otherwise, stay safe.

Regarding what bit rate is recommended, I would say to stay around 1500 Kb/sec for the ceiling (that's kilobits, not kilobytes). Again, this is simply a matter of math: 2 x CD-ROM read rates are about 150 KB/sec (that's kilobytes). 1500 kilobits = 187.5 kilobytes, so you're already outclassing the base level of drives that still exist.

Of course, VERY few people still use a 2X CD-ROM reader, and if they do, I pity them. Still, 4X is more common, and that's 300KB/sec.

Remember, the fastest CD-ROM reads happen at the outer tracks of a CD, where data gets burned last. That means that unless you are filling up the whole CD with data, you're not ever going to be reaching the maximum read rates of your CD drive. Furthermore, the published ceilings for all CD-ROM drives are strictly theoretical, and largely exaggerated to begin with, so just beware of the marketing behind the numbers. I've never seen a CD actually read at 52X. It just doesn't happen.

That being said, you can certainly push these limits with your project if maximizing quality is worth ticking off a few old schoolers out there. To me, as long as the source is clean and beautiful to begin with, 1500 Kb/sec should be a gracious plenty to pull it off on any project I produce.

[Lorne]

Re: I got to know, What Codec do I use...

Remember, the fastest CD-ROM reads happen at the outer tracks of a CD, where data gets burned last. That means that unless you are filling up the whole CD with data, you're not ever going to be reaching the maximum read rates of your CD drive.

Some burning software will let you choose which files get burned first or last. For example, Nero lets you assign a priority to each file (Low, Medium or High) that determines where the file gets placed relative to the other files that are being burned. Unless you specifically tell your burning software to burn a file last (e.g. in Nero, right-click, choose Properties, and set its priority to "High"), where it ends up on the CD will be left entirely up to fate. To put it another way, even if you burn 700 MB of data, if your movie is the first file burned, it will be on the inside of the disc.

This also assumes CAV (constant angular velocity) drives are being used, which read data faster from the outer tracks...CLV (constant linear velocity) drives would keep the same. I think all CD-ROM readers are CAV, though.

Then there's those super-sampling drives from a couple years back, with 16 lasers reading in parallel to simulate a faster read speed across the entire disc. (I forget what they were called...they were super fast, but prone to mechanical problems.)

[eric_darling]

Re: I got to know, What Codec do I use...

Good points, all, Lorne.

Of course, you'd need to have a pretty big project to be able to get to the physical outer tracks anyway. Most of my CD-ROM projects are considerably smaller than 700 MB. I assume other developers experience the same?

[Joe Sloppy]

Re: I got to know, What Codec do I use...

Thanks again, I should have also asked this..

What about a standard resolution for movies, whats everyone using, I have been just picking 640x480 sinces it seems to be the lowest resolution my screen can go...???

[eric_darling]

Re: I got to know, What Codec do I use...

Actually, that's really high for a video delivered on CD-ROM. You want to deliver 320x240 or thereabouts for CD-ROM purposes. You can always scale it up, or issue the full screen command to the player.