[Ffmpeg-devel] OptionDef to AVOption migration problems

[Panagiotis Issaris]

Hi,

I've run into several issues now regarding the migration of the OptionDef 
options to AVOptions. 

One of them is that the defaults for the AVOptions are being stored 
in "avctx_opts". The problem with this is that AVCodecContext contains one 
field "bit_rate" which is used for both audio and video bitrates. When the 
parameters are set in the per-stream AVCodecContext,
it isn't an issue, but for the defaults it is as there is only one for both 
video and audio related defaults.

Another problem occurs with some parameters which have units which are not 
common, such as lmax, which scales the parameter with 112:
 1508 #define FF_QP2LAMBDA 118 ///< factor to convert from H.263 QP to lambda
 ...
 2322 static void opt_lmax(const char *arg)
 2323 {
 2324     video_lmax = atof(arg)*FF_QP2LAMBDA;
 2325 }

Other parameters have range checks which can't be done using AVOptions for the 
moment. In an AVOption you specify a maximum and a minimum. It can't be 
specified whether the boudaries are inclusive or not.
 2315     if (video_qscale <= 0 ||
 2316         video_qscale > 255) {
 2317         fprintf(stderr, "qscale must be > 0.0 and <= 255\n");

Some parameters such as "-s" parse the argument to get the frame width and 
height, but as there is no possibility to register a callback function in the 
AVOption struct, this can't be parsed. 

Any suggestions would be greatly appreciated :)

With friendly regards,
Takis