[FFmpeg-devel] aalib video filter patch review request

iamtakingiteasy at eientei.org iamtakingiteasy at eientei.org
Sun Jun 29 17:13:39 CEST 2014

Thank you, Stefano Sabatini and Michael Niedermayer for your replies, i 
have considered your notes and re-written aalib filter according to 

This results in three commits, which will follow this message, as stated 
in [1] keeping them separate simplifies reviewing process:

* [lavfi][aalib][PATCH] lavfi: Generalization of freetype/fontconfig 
font loading.
* [lavfi][aalib][PATCH] lavfi: Proposed changes to vf_drawtext filter to 
use new fontconfig utils.
* [lavfi][aalib][PATCH] lavfi: add aalib video filter.

The first patch is not altering anything functional, but allows to 
second and third patch to be applied.
The main idea is to extract common parts (FreeType2 and Fontconfig) of 
font discovery and loading from vf_aa and vf_drawtext and place them 
into freetypeutils.h/c files.

The second patch is, as far i understand, should be maintained by some 
other person, but i wasn't able to find who is in charge for vf_drawtext 
files by looking at MAINTAINERS file, yet still it is only a suggestion 
how to change vf_drawtext.c in order to incorporate new 
freetype/fontconfig mechanism.

And finally the last patch is the rewritten vf_aa.c.
Answering to question of Stefano Sabatini:

>> +static struct aa_driver vf_driver = {
>> +    .shortname = "vf",
>> +    .name = "video filter driver",
>> +    .init = vf_driver_init,
>> +    .uninit = vf_driver_uninit,
>> +    .setattr = vf_driver_setattr,
>> +    .getsize = vf_driver_getsize,
>> +    .print = vf_driver_print,
>> +    .gotoxy = vf_driver_gotoxy
>> +};

> what's this good for?

This is a aa_driver custom driver descriptor, as aa_driver' methods are 
only means to actually receive any updates on aa-processed framebuffer.


Also, one open question is the libavfilter/version.h incrementing, not 
sure how all this three patches should operate on this matter. Currently 
they're all setting minor version to 10 (+1), but possibly application 
of each one should increment either it or micro version of lavfi, please 

[1] http://ffmpeg.org/developer.html

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