[vlc-devel] [PATCH 2/2] Add VideoToolbox based decoder

[Rémi Denis-Courmont]

Le 2015-02-03 18:21, Jean-Baptiste Kempf a écrit :
> On 03 Feb, Rémi Denis-Courmont wrote :
>> Le 2015-02-03 13:56, Jean-Baptiste Kempf a écrit :
>> >On 02 Feb, Rémi Denis-Courmont wrote :
>> >>> +    p_dec->fmt_out.i_codec = VLC_CODEC_YV12;
>> >>
>> >>YV12 for 10-bits seems very odd. Ditto for non-4:2:0.
>> >
>> >The VT library does the conversion and the dithering internally.
>>
>> Of course the GPU or video DSP would easily downsample. But by the 
>> time VLC
>> 3.0 comes out, and considering Apple's brand positioning, I would 
>> certainly
>> expect real 10-bits output support. So I think that forcing 8-bits 
>> here is a
>> bad idea even if it works.
>
> The problem so far, is that we request 8bit output.
>
> We could request 10-bits or 8bits 422 output, if we can detect that
> early enough.

For H.264, the chroma subsampling and the sample depth are specified in 
the SPS, just like the profile and level (which this code path already 
checks).

For older codecs, I don't think 10-bits is possible at all.

-- 
Rémi Denis-Courmont