[MPlayer-users] Bitrates and File Size

Ethan John thaen at u.washington.edu
Mon Aug 25 21:37:28 CEST 2003

> Please, don't reply to other threads to write to the list. Just select 
> writing
> a new message instead of replying to older thread. (ofc when you aren't
> continuing the thread.) it's rather rude and will make some ppl miss 
> your
> mails.
How were you aware that I did this? In my original email, there was 
nothing to indicate that I did this -- I had a unique subject, deleted 
the quoted text... I'm very confused.

> AFAIK this is explained in encoding-tips.txt, check it again.
Please, I'm not stupid. I read the doc. It's mentioned briefly at the 
end, but not to my satisifaction.

>> But in practice, this number is too small -- it yields files in the
>> 600-650 MB range.
> IMHO  you should target 700MB.
I'm not sure you even read what I was saying -- I didn't mention a 
specific target file size. The formula I think should be correct, 
should be correct for _any_ target file size given a constant bit rate.

> Hint: use 3 pass technique. mencoder will tell you a suggested bitrate.
MEncoder's bitrate suggestions are LUDICRIOUSLY small compared to the 
actual bitrates you can get. I used to use these values, but my movies 
came out to be around 500 MB. Those suggested bitrates are bogus.

> If mencoder outputs a file much less (as in more than 3MB) smaller 
> than you
> had expected, check out divx2pass.log, calc quantizer avg. If it's 2 
> or very
> close to 2, you shouldn't be scaling down that much. If it's less than 
> 2 you
> really should limit it.. But there's in the docs about this too. Or if 
> you
> are fine with the current video resolution, give more bits to the 
> audio side.
I'll check the file. This may be in the docs, but if it is, it's not 
easy to find and not well explained. Like I said, i've read the docs 
inside and out. The video resolution is usually 640x304 or whatever the 
aspect of the movie is (I calculate it based on the crop information, 
automatically). No matter what, it's weird that a movie will have 
noticeable visual artifacts, still not get up to the bitrate I 
originally suggested, and the file size will be smaller than the 

Besides, my question wasn't about target file size, it was about why 
the bitrate of a movie doesn't accurately determine it's file size. 
Very simple question if you know the answer, I would guess.

ethan john
Apple Campus Representative
University of Washington

"Every year a few brave programmers take a shower for the first time, 
and are found dead in the shower a few days later. The bottle of 
shampoo reads, 'Lather, Rinse, Repeat.' "
"The bug was fixed in version 1.1. It now reads, 'Lather, Rinse, Repeat 
as desired.' "

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