On Fri, 10 May 2019 12:58:43 +0200, Hans Verkuil wrote:
> On 5/10/19 12:28 PM, Michael Tretter wrote:
> > On Fri, 10 May 2019 10:28:53 +0200, Hans Verkuil wrote:
> >> On 5/3/19 2:20 PM, Michael Tretter wrote:
> >>> Add a V4L2 mem-to-mem driver for Allegro DVT video IP cores as found in
> >>> the EV family of the Xilinx ZynqMP SoC. The Zynq UltraScale+ Device
> >>> Technical Reference Manual uses the term VCU (Video Codec Unit) for the
> >>> encoder, decoder and system integration block.
> >>>
> >>> This driver takes care of interacting with the MicroBlaze MCU that
> >>> controls the actual IP cores. The IP cores and MCU are integrated in the
> >>> FPGA. The xlnx_vcu driver is responsible for configuring the clocks and
> >>> providing information about the codec configuration.
> >>>
> >>> The driver currently only supports the H.264 video encoder.
> >>>
> >>> Signed-off-by: Michael Tretter <m.tretter@xxxxxxxxxxxxxx>
> >>> ---
>
> <snip>
>
> >>> +static int allegro_try_fmt_vid_out(struct file *file, void *fh,
> >>> + struct v4l2_format *f)
> >>> +{
> >>> + f->fmt.pix.field = V4L2_FIELD_NONE;
> >>> +
> >>> + f->fmt.pix.width = clamp_t(__u32, f->fmt.pix.width,
> >>> + ALLEGRO_WIDTH_MIN, ALLEGRO_WIDTH_MAX);
> >>> + f->fmt.pix.height = clamp_t(__u32, f->fmt.pix.height,
> >>> + ALLEGRO_HEIGHT_MIN, ALLEGRO_HEIGHT_MAX);
> >>
> >> Shouldn't this be rounded up to the macroblock size? Or is the encoder
> >> smart enough to do the padding internally?
> >
> > The driver sends a message with the visible size of the raw frames
> > (without macroblock alignment) to the encoder firmware. Therefore, the
> > encoder firmware is responsible for handling the padding to macroblock
> > size.
>
> Please add a comment describing this. It is unusual for encoders to be
> able to do this so it is good to document this.
OK.
>
> >
> > Furthermore, the encoder requires that the stride is 32 byte aligned.
> > Therefore, we naturally have a macroblock alignment regarding the
> > width, but not regarding the height. This limitation is already
> > included in the bytesperline field.
>
> Ack.
>
> >
> >>
> >>> +
> >>> + f->fmt.pix.pixelformat = V4L2_PIX_FMT_NV12;
> >>> + f->fmt.pix.bytesperline = round_up(f->fmt.pix.width, 32);
> >>> + f->fmt.pix.sizeimage =
> >>> + f->fmt.pix.bytesperline * f->fmt.pix.height * 3 / 2;
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static int allegro_s_fmt_vid_out(struct file *file, void *fh,
> >>> + struct v4l2_format *f)
> >>> +{
> >>> + struct allegro_channel *channel = fh_to_channel(fh);
> >>> + int err;
> >>> +
> >>> + err = allegro_try_fmt_vid_out(file, fh, f);
> >>> + if (err)
> >>> + return err;
> >>> +
> >>> + channel->width = f->fmt.pix.width;
> >>> + channel->height = f->fmt.pix.height;
> >>> + channel->stride = f->fmt.pix.bytesperline;
> >>> + channel->sizeimage_raw = f->fmt.pix.sizeimage;
> >>> +
> >>> + channel->colorspace = f->fmt.pix.colorspace;
> >>> + channel->ycbcr_enc = f->fmt.pix.ycbcr_enc;
> >>> + channel->quantization = f->fmt.pix.quantization;
> >>> + channel->xfer_func = f->fmt.pix.xfer_func;
> >>> +
> >>> + channel->level =
> >>> + select_minimum_h264_level(channel->width, channel->height);
> >>> + channel->sizeimage_encoded =
> >>> + estimate_stream_size(channel->width, channel->height);
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static int allegro_g_selection(struct file *file, void *priv,
> >>> + struct v4l2_selection *s)
> >>> +{
> >>> + struct v4l2_fh *fh = file->private_data;
> >>> + struct allegro_channel *channel = fh_to_channel(fh);
> >>> +
> >>> + if (!V4L2_TYPE_IS_OUTPUT(s->type))
> >>> + return -EINVAL;
> >>> +
> >>> + switch (s->target) {
> >>> + case V4L2_SEL_TGT_CROP:
> >>> + case V4L2_SEL_TGT_CROP_DEFAULT:
> >>> + case V4L2_SEL_TGT_CROP_BOUNDS:
> >>> + s->r.left = 0;
> >>> + s->r.top = 0;
> >>> + s->r.width = channel->width;
> >>> + s->r.height = channel->height;
> >>
> >> I don't think this is quite right. The CROP target should return the visible
> >> width/height (e.g. 1920x1080) whereas the other two targets should return the
> >> coded width/height (e.g. 1920x1088 when rounded to the macroblock alignment).
> >>
> >> Note: if the hardware doesn't require that the raw frame is macroblock aligned,
> >> then I need to think a bit more about how the selection handling should be
> >> done.
> >
> > The driver internally calculates the coded width/height in macroblocks
> > and cropping and writes it to the SPS. Currently, this isn't exposed to
> > userspace, because I don't see a need to tell the userspace about that.
> >
> > If there is a reason to expose this to userspace, I am fine with
> > implementing that.
>
> There really is no need for the selection API at all. Just drop both
> G and S_SELECTION from the driver. Let me know if the compliance test
> fails for drivers without selection support, I'll have to fix the test
> in that case.
The compliance test for VIDIOC_S_FMT fails with the following message
if G_SELECTION is not implemented:
fail: v4l2-test-formats.cpp(836): sel.r.width != fmt.g_width()
test VIDIOC_S_FMT: FAIL
I will send a patch for v4l2-compliance.
Michael
>
> >
> >>
> >>> + break;
> >>> + default:
> >>> + return -EINVAL;
> >>> + }
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static int allegro_s_selection(struct file *file, void *priv,
> >>> + struct v4l2_selection *s)
> >>> +{
> >>> + return -EINVAL;
> >>> +}
> >>
> >> You have to implement setting the CROP target for an encoder. Otherwise
> >> you cannot tell the encoder what the visible width/height should be.
> >>
> >> Just setting the format to 1920x1080 will actually return 1920x1088 and
> >> set the visible width/height to that as well as per the encoder spec.
> >>
> >> So applications have to call S_SELECTION afterwards to make sure the
> >> visible rectangle is set correctly.
> >>
> >> Note that the compliance test in my vicodec branch doesn't check for this
> >> (yet). It's still work in progress :-)
> >
> > Agreed, if I actually need to align the size to macroblocks. If not, I
> > could support S_SELECTION by adjusting the SPS, but I understand that
> > it is not required by the spec.
>
>
> >>> +static int allegro_enum_framesizes(struct file *file, void *fh,
> >>> + struct v4l2_frmsizeenum *fsize)
> >>> +{
> >>> + switch (fsize->pixel_format) {
> >>> + case V4L2_PIX_FMT_H264:
> >>> + case V4L2_PIX_FMT_NV12:
> >>> + break;
> >>> + default:
> >>> + return -EINVAL;
> >>> + }
> >>> +
> >>> + if (fsize->index)
> >>> + return -EINVAL;
> >>> +
> >>> + fsize->type = V4L2_FRMSIZE_TYPE_CONTINUOUS;
> >>> + fsize->stepwise.min_width = ALLEGRO_WIDTH_MIN;
> >>> + fsize->stepwise.max_width = ALLEGRO_WIDTH_MAX;
> >>> + fsize->stepwise.step_width = 1;
> >>> + fsize->stepwise.min_height = ALLEGRO_HEIGHT_MIN;
> >>> + fsize->stepwise.max_height = ALLEGRO_HEIGHT_MAX;
> >>> + fsize->stepwise.step_height = 1;
> >>
> >> I would expect this to be STEPWISE with the macroblock size as
> >> the step size.
>
> Based on your HW capabilities you can ignore this comment as well.
>
> >>
> >>> +
> >>> + return 0;
> >>> +}
>
> Regards,
>
> Hans
>
