[MPlayer-dev-eng] Lots of stuff for NUT

[Rich Felker]

On Sat, Dec 31, 2005 at 07:30:30AM +0200, Oded Shimon wrote:
> In other news:
> 
> I've completed a frame code table generator! And it kicks ass quite a bit. 
> Brings the overhead to 1 byte per packet in audio and 2 bytes per packet in 
> video.
> The general idea:
> 
> 1. Store ALL possible combinations of (stream, pts diff, size, is_key) in a 
>    hash, saying how many times each combination appeared.
> 2. Pick the top 10 items in the hash, and write explicit frame codes which 
>    handle them. This just about takes care of the entire audio stream, it 
>    appears almost all mp3 packets have the exact same size.
> 3. Take what is left in the hash, and resort by combinations of (stream, 
>    size, is_key) (discard size).
> 4. According to how "popular" a combination is, allocate it whatever is 
>    left of the ~230 frame codes where only msb needs to be written after 
>    frame code. The more popular, the bigger "mul" it gets.
> 
> Here's the funny thing, in part 4, when deciding how popular a combination 
> is, I had a bug at first making it decide not by how many packets there 
> were with this combination, but by how many different sizes there were for 
> this combinations (how many sub-combinations this combination had). It 
> actually gave (slightly) BETTER results...
> 
> Does anyone have any ideas to improove this generator?
> BTW, it's written in perl and it's slow as fuck, takes about 6 seconds to 
> generate a table.

Anyone can make an optimal framecode table if you know the content in
advance. The tricky thing is making good framecode tables that work
well in just one pass.

Rich