Max I Frames on DVDs

[SCDVD]

This is more a theoretical question than a practical one. If a MPEG-2 file was made with all I frames and no P or B frames and made into a DVD, would it play without problems in a DVD player? I can't think of a reason to do this, but I am curious if it would work if this were done. I realize that this would reduce the content time a great deal because it would eliminate the compression benefit of MPEG-2 but I'm still curious if this is within spec if it were done.

[jman98]

Would it play without problems? I think it probably would. Here's why. I frames are full frames, so they don't tax CPUs and decoding chips like B and P frames do where comparisons and calculations must be made.

However, while there are upper limits on GOPs (NTSC GOPs cannot exceed 18 and I think it's 15 for PAL), I can't find any solid evidence on a lower limit. If there is some kind of lower limit for a GOP where the size must > 1, then your plan wouldn't be line with DVD specs. Maybe somebody here has some hard evidence that DVD GOPs must be > 1, but a quick search by me didn't turn up anything.

[lordsmurf]

I've done all I-frames before. I often see commercial DVDs with mixes of IP-only or I-only. BJ_M could tell you more, he's dealt with that on a pro level before. Custom compression on a per-scene basis.