[theora-dev] Theora file size

[Unga]

Hi

I was surprised with size of Theora files and thought
of feedback.

Following 1minute duration Theora and Xvid files were
made from a y4m file. The resolution is 1280x720:

1. Xvid	17MB
2. Ogg/Theora Q7   31MB
3. Ogg/Theora Q8   38MB
4. Ogg/Theora Q9   49MB
5. Ogg/Theora Q10  61MB

The Xvid file was made using mencoder by 2 passes with
following options:
bitrate=2500:autoaspect:chroma_opt:vhq=4:bvhq=1:quant_type=mpeg:pass=1

The encoder_example was used to create Ogg/Theora
files.

It was noted y4m to Theora encoding was the fastest 
that I have ever seen. The Q9 Ogg/Theora took only 2
minutes 35 seconds. But the files created were way too
large compared to Xvid. The Xvid quality was very
good, it may be equivalent to Ogg/Theora Q9 or Q10,
but its file size is just 17MB. But where as Q10
Ogg/Theora is nearly 4 times bigger than similar Xvid!
Q7 Ogg/Theora quality was quite acceptable but its
still twice bigger than Xvid. 

In fact, it doesn't matter if it takes more time to
encode if the resulting file size is smaller.  Can we
achieve smaller file sizes with Theora without
compromising quality?

Best Regards
Unga

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