[Mplayer-cvslog] CVS: main/libmpcodecs ve_lavc.c,1.10,1.11

[Michael Niedermayer]

Hi

On Sunday 21 April 2002 23:58, Arpi wrote:
> Hi,
>
> > support for new stuff (lavc internal 2pass, ...)
>
> hmm, could you tell us how does it work?
> (and what is teh meaning of new params, for the docs)
sure, iam allready workingon that ... its just finished see below
----------------------------
Description of what all thouse libavcodec rate cotrol options do ...

Flags:	1=used in 1pass & pass1 of 2
	2=used in pass2 of 2
        c=used in fixed quantizer mode
Note: changing some options between pass1 & 2 can reduce the quality

12  vqmin		minimum I/P Quantizer
12  vqmax		maximum I/P Quantizer
12c vmax_b_frames	maximum number of b frames for between each I/P frame
12  vratetol		file size tolerance 
			larger means that the filesize will be less accurate but the quality will 
be higher
12c vhq			HQ mode, macro blocks will be encoded multiple times and the best 
(smallest) will be used
12c v4mv		4 Motion vectors per macroblock (can only be used in HQ mode and is 
buggy with b-frames currently)
12  vpass		select internal first pass or second pass of 2pass mode
12  vqcomp		quantizer compression
			1.0 means constant rate (high motion scenes look bad)
                        0.0 means constant quality (low motion scenes look 
bad)
2   vrc_strategy	0,1,2 different strategies to decide which frames should get 
which quantizer
1   vqblur		quantizer blur
2   vb_strategy		strategy to choose between i/p/b frames
			0 allways use max b
                        1 avoid b frames in high motion / scene change (can 
lead to filesize miss predicton)
1   vqdiff		maximum quantizer difference between frames (ignores b-frames)
12  vbitrate		bitrate
12c vme			motion estimation
                        0 none
                        1 full search (too slow)
                        2 log
                        3 phods
                        4 EPZS
                        5 X1
c   vqscale		2-31 quantizer (low=hq, high=lq)
12  vb_qfactor		quantizer factor between b and i/p frames (larger means 
higher quantizer for b frames)
12c keyint		keyframe interval (larger means smaller file but lower quality)
			>300 are not recomanded
-------------------------------
>
> i can't see where are the statistics from 1st pass saved and where is it
> send back to teh codec in teh 2nd pass? or is it all handled inside
lavc_stats.txt

> libavcodec? then divx4-type 2pass code should be removed from ve_lavc.c
hmm, yes, it can be removed

[...]

Michael