Orchid XP v8 wrote:

> I should probably just start over with a better test video!

OK, so I started again, this time with a custom-rendered Electric Sheep 
video. In other words, it features intricate fractal detail, vibrant 
colours, full-frame complex swirling motion, and high-quality motion blur.

S026m-Anim2.avi

720x576 pixels, 24 bits/pixel, 25 frames/second, 420 frames.

Uncompressed:         498 MB

Huffyuv: 0:08 encode, 105 MB
FFV1:    0:37 encode, 176 MB

MPEG1:   0:16 encode, 3.40 MB
Theora:  0:28 encode, 4.16 MB
DivX 3:  0:08 encode, 1.96 MB
XviD:    0:12 encode, 2.11 MB
H.264:   0:38 encode, 4.73 MB

Well that definitely says... something. (In particular, FFV1 now does 
drastically worse than Huffyuv, despite being much slower to encode and 
too slow for realtime codecing.) But how good does the lossy video look?

All of the video was encoding at "900 Kbit/sec average bitrate". And 
yet, they differ fairly widely in file size. Perhaps unsurprisingly 
then, we find the following:

- MPEG1 looks *horrible*! I mean, *really* horrible. (Recall that with 
my previous test, 900 Kbit MPEG1 actually looked not much different from 
the uncompressed original. Clearly I picked a test case that was far too 
easy!)

- DivX 3 looks even worse than MPEG1. And not by a small margin.

- XviD looks better than MPEG1.

- Theora looks quite a bit better than XviD.

- H.264 looks really very good indeed. Considering the file is over 100x 
smaller than the original, there is surprisingly little distortion.

So we have roughly

   DivX < MPEG1 < XviD < Theora < H.264

This follows the file sizes almost exactly, except for MPEG1.

I had assumed that given the same average bitrate, all the codecs would 
produce a file roughly the same size. This isn't really the case here. I 
guess now I'll have to spend a few hours trying to get each codec to 
produce a file of roughly the same size so I can compare those...

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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