Re: [Mjpeg-developer] lav2divx/yuv2divx OpenDIVX bitrate

[Shawn <mj...@at...>]

On Thu, Feb 28, 2002 at 03:22:29PM -0700, K. Leif D. Van Horn wrote:
| 1. Here are some excerpts from the OpenDivX distribution.
|    rc_period           // the intended rate control averaging period 
|                        // (2000 is common)
|    rc_reaction_period  // the reaction period for rate control (10 is common)
|    rc_reaction_ratio   // the ratio for down/up rate control (20 is common)

One wonders: what are these measured in?  I suppose I'll need to go digging
through documentation... :)

|    quality             // the quality of compression (1 - fastest, 5 - best )
|    max_quantizer       // the upper limit of the quantizer
|    min_quantizer       // the lower limit of the quantizer
| 
|     Quantizer values are not explained in the document.
| 
| 2. The values are written to and read from ~/.avirc

Hmmm.  Should we then hardcode defaults into our utilities without the
ability to use either the avirc values or user-specified ones?
 
| 3. The values can range and appear to be useful.

It looks like they might be...
 
| 4. I don't know of any other fourcc that uses these specific names.
|    There may be similarities, however.

Hmmm.  A quick check shows that there's a DirectShow win32 (DIVX4) dll, and
an ffmpeg handler for the fourcc "DIVX" (on my system at least), in addition
to the opendivx/libdivx ones.  I wonder if they also accept the same
configuration values.

More digging is required.

Where I'm going with this is that I'm not certain that hardcoding these
values into the utilities is the best path.  WE may want a more flexible
solution (Hmmm... something like "--codec-option quality=5 --codec-option
rc_period=2000" perhaps? Or kept in extension tags in the Y4M or edit list
meta data?)