[FFmpeg-devel] [PATCH] lavfi: add ff_all_channel_layouts internal symbol

[Stefano Sabatini]

On date Friday 2011-09-09 03:25:00 +0200, Michael Niedermayer encoded:
> On Thu, Sep 08, 2011 at 02:12:53AM +0200, Stefano Sabatini wrote:
> [...]
> > 8 channels (FC|LFE|BL|BR|SL|SR|DL|DR)
> > 8 channels (FL|FR|BL|BR|SL|SR|DL|DR)
> > 9 channels (FL|FR|LFE|BL|BR|SL|SR|DL|DR)
> > 9 channels (FL|FR|FC|BL|BR|SL|SR|DL|DR)
> 
> > 7.1+downmix
> 
> this is 10 channels
> 
> 
> > 6 channels (FC|BC|SL|SR|DL|DR)
> > 7 channels (FC|LFE|BC|SL|SR|DL|DR)
> > 7 channels (FL|FR|BC|SL|SR|DL|DR)
> > 8 channels (FL|FR|LFE|BC|SL|SR|DL|DR)
> > 8 channels (FL|FR|FC|BC|SL|SR|DL|DR)
> > 9 channels (FL|FR|FC|LFE|BC|SL|SR|DL|DR)
> > 
> > with some 9-channels formats, which are not supported by libavfilter
> > (max 8 channels).
> 
> we should raise this to 16 on the next ABI bump

Looks a good idea.

> 
> 
> [...]
> 
> my suggestion:
> 
> AVFilterFormats *avfilter_all_channel_layouts(void)
> {
>     static int64_t cls[] = {
> #define A(x) (x), (x)|AV_CH_LOW_FREQUENCY
> #define B(x) A(x|AV_CH_FRONT_CENTER), A(x|AV_CH_FRONT_LEFT|AV_CH_FRONT_RIGHT), A(x|AV_CH_FRONT_CENTER|AV_CH_FRONT_LEFT|AV_CH_FRONT_RIGHT)
> #define C(x) B(x), B(x|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT), B(x|AV_CH_BACK_CENTER)
> #define D(x) C(x), C(x|AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT)
>         D(0), D(AV_CH_STEREO_LEFT|AV_CH_STEREO_RIGHT)
>     };
> 
>     for (i = 0; i < FF_ARRAY_ELEMS(cls); i++) {
>         if (get_channel_layout_nb_channels(cls[i]) > 8) {
>             cls[i]=AV_CH_FRONT_CENTER;
>         }
>     }
>     return avfilter_make_format64_list(cls);
> }

My problem is that I need the list as an int64_t list (for use in the
audio sink). I could of course convert the formats list to int64_t,
but would be awkward. That's why I proposed a static int64_t array.
-- 
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