Re: [PATCH v7 5/9] media: venus: vdec: add video decoder files

[Stanimir Varbanov <stanimir.varbanov@linaro.org>]

Hi,

On 24.03.2017 20:21, Nicolas Dufresne wrote:
> Le vendredi 24 mars 2017 à 15:41 +0100, Hans Verkuil a écrit :
>>> +static const struct venus_format vdec_formats[] = {
>>> +     {
>>> +             .pixfmt = V4L2_PIX_FMT_NV12,
>>> +             .num_planes = 1,
>>> +             .type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE,
>>
>> Just curious: is NV12 the only uncompressed format supported by the
>> hardware?
>> Or just the only one that is implemented here?

yes, at least to my knowledge (except below UBWC).

>
> The downstream kernel[0], from Qualcomm have:
>
>         {
>                 .name = "UBWC YCbCr Semiplanar 4:2:0",
>                 .description = "UBWC Y/CbCr 4:2:0",
>                 .fourcc = V4L2_PIX_FMT_NV12_UBWC,
>                 .num_planes = 2,
>                 .get_frame_size = get_frame_size_nv12_ubwc,
>                 .type = CAPTURE_PORT,
>         },
>         {
>                 .name = "UBWC YCbCr Semiplanar 4:2:0 10bit",
>                 .description = "UBWC Y/CbCr 4:2:0 10bit",
>                 .fourcc = V4L2_PIX_FMT_NV12_TP10_UBWC,
>                 .num_planes = 2,
>                 .get_frame_size = get_frame_size_nv12_ubwc_10bit,
>                 .type = CAPTURE_PORT,
>         },
>
> I have no idea what UBWC stands for. The performance in NV12 is more
> then decent from my testing. Though, there is no 10bit variant.

UBWC is some kind of compressed format for NV12 [1]. This format is 
applicable for the newer venus hardware revisions and I planed to add it 
later on (when Adreno GPU driver starts handle it).

regards,
Stan

[1] 
https://android.googlesource.com/kernel/msm/+/android-7.1.0_r0.2/include/media/msm_media_info.h#151