[FFmpeg-devel] [PATCH v5 1/5] libavcodec: VAAPI support infrastructure

[Mark Thompson]

On 31/01/16 16:24, Mark Thompson wrote:
> On 31/01/16 16:13, wm4 wrote:
>> On Sat, 30 Jan 2016 22:11:52 +0000
>> Mark Thompson <sw at jkqxz.net> wrote:
>>> +
>>> +static AVClass vaapi_class = {
>>> +    .class_name = "vaapi",
>>> +    .item_name  = av_default_item_name,
>>> +    .version    = LIBAVUTIL_VERSION_INT,
>>> +};
>>> +static AVClass *vaapi_log = &vaapi_class;
>>> +
>>
>> I'll give a more thorough review tomorrow, but let me just point out
>> that this is not really the point of the log mechanism. It should be
>> bound to an actual instance, like the vaapi hw context or whatever. We
>> hope to get rid of the global log callback one day, and then all av_log
>> calls have to go to an instance of some sort (so that it can find the
>> log callback), even if this doesn't matter today yet.
>>
> 
> I wanted to put an AVClass into the hardware context structure, but it doesn't work without breaking the compatibility with struct vaapi_context (because it has to be the first thing in the structure).
> 
> Without that, there is just nothing to bind it to in many of those functions.
> 
> - Mark
> 

And then I see the hackaround just after sending...

struct {
    foo;
    const AVClass *class;
} bar;

av_log(&bar->class, ...);

Nasty, but I can use that.  (And not really worse than the existing "log" static variable.)

- Mark