encoding source in lossless divx

[bum]

Some time ago I was somewhere doing something which i cant remember because it was probably boring, and I had the idea of encoding source footage in divx, but in a lossy form. Now my use of the word lossy may be incorect because I dont realy know all the difference between lossy and lossless codecs. But I do know that with video in lossy each frame is drawn as a full frame while with lossless video codecs, only pixels that change colout from the last frame are put into the next frame. So what i mean by lossy divx is seting the max keyframe interval to 1, so effectively each frame is drawn in full. I was able to get the first vob of memories (26min44sec) down to 100MB. Sure for any sort of distribution it looked terrible, but its fine for editing if you bait and switch. And considering the ammount of space it takes up, it means alot more source footage can be stored, and pernamently.

so am i crazy ? am I totoaly missing the point of lossy codecs ? or will someone try my method of geting source footage. Hey, my latest vid looked fine (well, it had interlacing issue's, but now I've figured out how to fix them. thanx again AD ) .

[bum]

gah, i mixed up lossles and lossy. any mod mind changing the thread title ?

[Scintilla]

No, no, and more no.

"Lossless" means that what you get out is exactly pixel-for-pixel identical with what you put in, i.e., there's <i>no loss</i>, hence "loss-less". Examples: uncompressed RGB, ZIP, HuffYUV, Lagarith.

"Lossy" means that what you get out is <i>not</i> exactly the same as what you put in, i.e., there's a loss in quality. Examples: MPEG-1, MPEG-2, MPEG-4, DV, RLE, Cinepak, Indeo, etc.

It's as simple as that.

Now my use of the word lossy may be incorect because I dont realy know all the difference between lossy and lossless codecs. But I do know that with video in lossy each frame is drawn as a full frame while with lossless video codecs, only pixels that change colout from the last frame are put into the next frame.

You're talking about temporal (or inter-frame) compression.

DivX does use temporal compression (only drawing the pixels that change from the last in all non-keyframes), like all major distro codecs, but lossiness is something different (as I explained above).

So what i mean by lossy divx is seting the max keyframe interval to 1, so effectively each frame is drawn in full. I was able to get the first vob of memories (26min44sec) down to 100MB. Sure for any sort of distribution it looked terrible, but its fine for editing if you bait and switch. And considering the ammount of space it takes up, it means alot more source footage can be stored, and pernamently.

In other words, you made it so that every frame was a keyframe, so that only intra-frame (spatial) compression was used, thus (in all likelihood) getting around some of the problems of editing with distro codecs.
Well, sounds good, aside from the incorrect terminology.

so am i crazy ? am I totoaly missing the point of lossy codecs ?

Yes to both.

or will someone try my method of geting source footage.

It won't be me; I like my VOBs and scripts just fine.

[Scintilla]

ARGH.
/me embarks on half-dozenth double-post of the day

I should have mentioned, for further clarity:
It's theoretically possible for a lossless codec to use temporal (inter-frame) compression. I don't know if any actually do.
It's also possible (as you demonstrated) for a lossy codec NOT to use temporal compression. MJPEG and RLE are two other codecs that make every frame a keyframe and just perform spatial compression on each frame.

[Sir_Lagsalot]

Alparysoft, MSU, and CorePNG are all lossless codecs that can take advantage of delta frames, and technically Lagarith does too when Null frames are enabled.