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

[Nicolas Dufresne <nicolas@ndufresne.ca>]

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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?

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.

regards,
Nicolas

[0] https://android.googlesource.com/kernel/msm/+/android-7.1.0_r0.2/dr
ivers/media/platform/msm/vidc/msm_vdec.c#695

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