On 08/05/2020 14:28, Ezequiel Garcia wrote:
> Hi Hans,
>
> On Fri, 2020-05-08 at 12:27 +0200, Hans Verkuil wrote:
>> On 05/05/2020 15:41, Ezequiel Garcia wrote:
>>> From: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
>>>
>>> Add the VP9 stateless decoder controls plus the documentation that goes
>>> with it.
>>>
>>> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
>>> Signed-off-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx>
>>> ---
>>> .../userspace-api/media/v4l/biblio.rst | 10 +
>>> .../media/v4l/ext-ctrls-codec.rst | 581 ++++++++++++++++++
>>> drivers/media/v4l2-core/v4l2-ctrls.c | 242 ++++++++
>>> drivers/media/v4l2-core/v4l2-ioctl.c | 1 +
>>> include/media/v4l2-ctrls.h | 1 +
>>> include/media/vp9-ctrls.h | 510 +++++++++++++++
>>> 6 files changed, 1345 insertions(+)
>>> create mode 100644 include/media/vp9-ctrls.h
>>>
>>> diff --git a/Documentation/userspace-api/media/v4l/biblio.rst b/Documentation/userspace-api/media/v4l/biblio.rst
>>> index 3c9634173e82..e09102e572fd 100644
>>> --- a/Documentation/userspace-api/media/v4l/biblio.rst
>>> +++ b/Documentation/userspace-api/media/v4l/biblio.rst
>>> @@ -414,3 +414,13 @@ VP8
>>> :title: RFC 6386: "VP8 Data Format and Decoding Guide"
>>>
>>> :author: J. Bankoski et al.
>>> +
>>> +.. _vp9:
>>> +
>>> +VP9
>>> +===
>>> +
>>> +
>>> +:title: VP9 Bitstream & Decoding Process Specification
>>> +
>>> +:author: Adrian Grange (Google), Peter de Rivaz (Argon Design), Jonathan Hunt (Argon Design)
>>> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>>> index d0d506a444b1..fb657197b372 100644
>>> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>>> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>>> @@ -2668,6 +2668,587 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
>>> - ``padding[3]``
>>> - Applications and drivers must set this to zero.
>>>
>>> +.. _v4l2-mpeg-vp9:
>>> +
>>> +``V4L2_CID_MPEG_VIDEO_VP9_FRAME_CONTEXT(0..3) (struct)``
>>> + Stores VP9 probabilities attached to a specific frame context. The VP9
>>> + specification allows using a maximum of 4 contexts. Each frame being
>>> + decoded refers to one of those context. See section '7.1.2 Refresh
>>> + probs semantics' section of :ref:`vp9` for more details about these
>>> + contexts.
>>> +
>>> + This control is bi-directional:
>>> +
>>> + * all 4 contexts must be initialized by userspace just after the
>>> + stream is started and before the first decoding request is submitted
>>
>> Missing . at the end.
>>
>
> Oops, thanks for catching this.
>
>>> + * the referenced context might be read by the kernel when a decoding
>>> + request is submitted, and will be updated after the decoder is done
>>> + decoding the frame if the `V4L2_VP9_FRAME_FLAG_REFRESH_FRAME_CTX` flag
>>> + is set.
>>> + * contexts will be read back by user space before each decoding request
>>> + to retrieve the updated probabilities.
>>> + * userspace will re-initialize the context to their default values when
>>> + a reset context is required.
>>> +
>>> + .. note::
>>> +
>>> + This compound control is not yet part of the public kernel API and
>>> + it is expected to change.
>>> +
>>> +.. c:type:: v4l2_ctrl_vp9_frame_ctx
>>> +
>>> +.. cssclass:: longtable
>>> +
>>> +.. tabularcolumns:: |p{5.8cm}|p{4.8cm}|p{6.6cm}|
>>> +
>>> +.. flat-table:: struct v4l2_ctrl_vp9_frame_ctx
>>> + :header-rows: 0
>>> + :stub-columns: 0
>>> + :widths: 1 1 2
>>> +
>>> + * - struct :c:type:`v4l2_vp9_probabilities`
>>> + - ``probs``
>>> + - Structure with VP9 probabilities attached to the context.
>>> +
>>> +.. c:type:: v4l2_vp9_probabilities
>>> +
>>> +.. cssclass:: longtable
>>> +
>>> +.. tabularcolumns:: |p{1.5cm}|p{6.3cm}|p{9.4cm}|
>>> +
>>> +.. flat-table:: struct v4l2_vp9_probabilities
>>> + :header-rows: 0
>>> + :stub-columns: 0
>>> + :widths: 1 1 2
>>> +
>>> + * - __u8
>>> + - ``tx8[2][1]``
>>> + - TX 8x8 probabilities.
>>> + * - __u8
>>> + - ``tx16[2][2]``
>>> + - TX 16x16 probabilities.
>>> + * - __u8
>>> + - ``tx32[2][3]``
>>> + - TX 32x32 probabilities.
>>> + * - __u8
>>> + - ``coef[4][2][2][6][6][3]``
>>> + - Coefficient probabilities.
>>> + * - __u8
>>> + - ``skip[3]``
>>> + - Skip probabilities.
>>> + * - __u8
>>> + - ``inter_mode[7][3]``
>>> + - Inter prediction mode probabilities.
>>> + * - __u8
>>> + - ``interp_filter[4][2]``
>>> + - Interpolation filter probabilities.
>>> + * - __u8
>>> + - ``is_inter[4]``
>>> + - Is inter-block probabilities.
>>> + * - __u8
>>> + - ``comp_mode[5]``
>>> + - Compound prediction mode probabilities.
>>> + * - __u8
>>> + - ``single_ref[5][2]``
>>> + - Single reference probabilities.
>>> + * - __u8
>>> + - ``comp_mode[5]``
>>> + - Compound reference probabilities.
>>> + * - __u8
>>> + - ``y_mode[4][9]``
>>> + - Y prediction mode probabilities.
>>> + * - __u8
>>> + - ``uv_mode[10][9]``
>>> + - UV prediction mode probabilities.
>>> + * - __u8
>>> + - ``partition[16][3]``
>>> + - Partition probabilities.
>>> + * - __u8
>>> + - ``mv.joint[3]``
>>> + - Motion vector joint probabilities.
>>> + * - __u8
>>> + - ``mv.sign[2]``
>>> + - Motion vector sign probabilities.
>>> + * - __u8
>>> + - ``mv.class[2][10]``
>>> + - Motion vector class probabilities.
>>> + * - __u8
>>> + - ``mv.class0_bit[2]``
>>> + - Motion vector class0 bit probabilities.
>>> + * - __u8
>>> + - ``mv.bits[2][10]``
>>> + - Motion vector bits probabilities.
>>> + * - __u8
>>> + - ``mv.class0_fr[2][2][3]``
>>> + - Motion vector class0 fractional bit probabilities.
>>> + * - __u8
>>> + - ``mv.fr[2][3]``
>>> + - Motion vector fractional bit probabilities.
>>> + * - __u8
>>> + - ``mv.class0_hp[2]``
>>> + - Motion vector class0 high precision fractional bit probabilities.
>>> + * - __u8
>>> + - ``mv.hp[2]``
>>> + - Motion vector high precision fractional bit probabilities.
>>> +
>>> +``V4L2_CID_MPEG_VIDEO_VP9_FRAME_DECODE_PARAMS (struct)``
>>> + Specifies the frame parameters for the associated VP9 frame decode request.
>>> + This includes the necessary parameters for configuring a stateless hardware
>>> + decoding pipeline for VP9. The bitstream parameters are defined according
>>> + to :ref:`vp9`.
>>> +
>>> + .. note::
>>> +
>>> + This compound control is not yet part of the public kernel API and
>>> + it is expected to change.
>>> +
>>> +.. c:type:: v4l2_ctrl_vp9_frame_decode_params
>>> +
>>> +.. cssclass:: longtable
>>> +
>>> +.. tabularcolumns:: |p{1.5cm}|p{6.3cm}|p{9.4cm}|
>>> +
>>> +.. flat-table:: struct v4l2_ctrl_vp9_frame_decode_params
>>> + :header-rows: 0
>>> + :stub-columns: 0
>>> + :widths: 1 1 2
>>> +
>>> + * - __u32
>>> + - ``flags``
>>> + - Combination of V4L2_VP9_FRAME_FLAG_* flags. See
>>> + :c:type:`v4l2_vp9_frame_flags`.
>>> + * - __u16
>>> + - ``compressed_header_size``
>>> + - Compressed header size in bytes.
>>> + * - __u16
>>> + - ``uncompressed_header_size``
>>> + - Uncompressed header size in bytes.
>>> + * - __u8
>>> + - ``profile``
>>> + - VP9 profile. Can be 0, 1, 2 or 3.
>>> + * - __u8
>>> + - ``reset_frame_context``
>>> + - Frame context that should be used/updated when decoding the frame.
>>> + * - __u8
>>> + - ``bit_depth``
>>> + - Component depth in bits. Must be 8 for profile 0 and 1. Must 10 or 12
>>> + for profile 2 and 3.
>>> + * - __u8
>>> + - ``color_space``
>>> + - Specifies the color space of the stream. See V4L2_VP9_COLOR_SPACE_*
>>> + values. See :c:type:`v4l2_vp9_color_space`
>>
>> Ditto.
>>
>>> + * - __u8
>>> + - ``interpolation_filter``
>>> + - Specifies the filter selection used for performing inter prediction. See
>>> + :c:type:`v4l2_vp9_interpolation_filter`.
>>> + * - __u8
>>> + - ``tile_cols_log2``
>>> + - Specifies the base 2 logarithm of the width of each tile (where the
>>> + width is measured in units of 8x8 blocks). Shall be less than or equal
>>> + to 6.
>>> + * - __u8
>>> + - ``tile_rows_log2``
>>> + - Specifies the base 2 logarithm of the height of each tile (where the
>>> + height is measured in units of 8x8 blocks)
>>
>> Ditto
>>
>>> + * - __u8
>>> + - ``tx_mode``
>>> + - Specifies the TX mode. See :c:type:`v4l2_vp9_tx_mode`.
>>> + * - __u8
>>> + - ``reference_mode``
>>> + - Specifies the type of inter prediction to be used. See
>>> + :c:type:`v4l2_vp9_reference_mode`.
>>> + * - __u8
>>> + - ``padding``
>>> + - Needed to make this struct 64 bit aligned. Shall be filled with zeros.
>>> + * - __u16
>>> + - ``frame_width_minus_1``
>>> + - Add 1 to get the frame width expressed in pixels.
>>> + * - __u16
>>> + - ``frame_height_minus_1``
>>> + - Add 1 to to get the frame height expressed in pixels.
>>> + * - __u16
>>> + - ``frame_width_minus_1``
>>> + - Add 1 to to get the expected render width expressed in pixels. This is
>>> + not used during the decoding process but might be used by HW scalers to
>>> + prepare a frame that's ready for scanout.
>>> + * - __u16
>>> + - frame_height_minus_1
>>> + - Add 1 to get the expected render height expressed in pixels. This is
>>> + not used during the decoding process but might be used by HW scalers to
>>> + prepare a frame that's ready for scanout.
>>> + * - __u64
>>> + - ``refs[3]``
>>> + - Array of reference frame timestamps.
>>> + * - struct :c:type:`v4l2_vp9_loop_filter`
>>> + - ``lf``
>>> + - Loop filter parameters. See struct :c:type:`v4l2_vp9_loop_filter`.
>>> + * - struct :c:type:`v4l2_vp9_quantization`
>>> + - ``quant``
>>> + - Quantization parameters. See :c:type:`v4l2_vp9_quantization`.
>>> + * - struct :c:type:`v4l2_vp9_segmentation`
>>> + - ``seg``
>>> + - Segmentation parameters. See :c:type:`v4l2_vp9_segmentation`.
>>> + * - struct :c:type:`v4l2_vp9_probabilities`
>>> + - ``probs``
>>> + - Probabilities. See :c:type:`v4l2_vp9_probabilities`.
>>> +
>>> +.. c:type:: v4l2_vp9_frame_flags
>>> +
>>> +.. cssclass:: longtable
>>> +
>>> +.. tabularcolumns:: |p{1.5cm}|p{6.3cm}|p{9.4cm}|
>>> +
>>> +.. flat-table:: enum v4l2_vp9_frame_flags
>>> + :header-rows: 0
>>> + :stub-columns: 0
>>> + :widths: 1 2
>>> +
>>> + * - ``V4L2_VP9_FRAME_FLAG_KEY_FRAME``
>>> + - The frame is a key frame.
>>> + * - ``V4L2_VP9_FRAME_FLAG_SHOW_FRAME``
>>> + - The frame should be displayed.
>>> + * - ``V4L2_VP9_FRAME_FLAG_ERROR_RESILIENT``
>>> + - The decoding should be error resilient.
>>> + * - ``V4L2_VP9_FRAME_FLAG_INTRA_ONLY``
>>> + - The frame does not reference other frames.
>>> + * - ``V4L2_VP9_FRAME_FLAG_ALLOW_HIGH_PREC_MV``
>>> + - the frame might can high precision motion vectors.
>>> + * - ``V4L2_VP9_FRAME_FLAG_REFRESH_FRAME_CTX``
>>> + - Frame context should be updated after decoding.
>>> + * - ``V4L2_VP9_FRAME_FLAG_PARALLEL_DEC_MODE``
>>> + - Parallel decoding is used.
>>> + * - ``V4L2_VP9_FRAME_FLAG_X_SUBSAMPLING``
>>> + - Vertical subsampling is enabled.
>>> + * - ``V4L2_VP9_FRAME_FLAG_Y_SUBSAMPLING``
>>> + - Horizontal subsampling is enabled.
>>> + * - ``V4L2_VP9_FRAME_FLAG_COLOR_RANGE_FULL_SWING``
>>> + - The full UV range is used.
>>> +
>>> +.. c:type:: v4l2_vp9_ref_id
>>> +
>>> +.. cssclass:: longtable
>>> +
>>> +.. tabularcolumns:: |p{1.5cm}|p{6.3cm}|p{9.4cm}|
>>> +
>>> +.. flat-table:: enum v4l2_vp9_ref_id
>>> + :header-rows: 0
>>> + :stub-columns: 0
>>> + :widths: 1 2
>>> +
>>> + * - ``V4L2_REF_ID_LAST``
>>> + - Last reference frame.
>>> + * - ``V4L2_REF_ID_GOLDEN``
>>> + - Golden reference frame.
>>> + * - ``V4L2_REF_ID_ALTREF``
>>> + - Alternative reference frame.
>>> + * - ``V4L2_REF_ID_CNT``
>>> + - Number of reference frames.
>>> +
>>> +.. c:type:: v4l2_vp9_tx_mode
>>> +
>>> +.. cssclass:: longtable
>>> +
>>> +.. tabularcolumns:: |p{1.5cm}|p{6.3cm}|p{9.4cm}|
>>> +
>>> +.. flat-table:: enum v4l2_vp9_tx_mode
>>> + :header-rows: 0
>>> + :stub-columns: 0
>>> + :widths: 1 2
>>> +
>>> + * - ``V4L2_VP9_TX_MODE_ONLY_4X4``
>>> + - Transform size is 4x4.
>>> + * - ``V4L2_VP9_TX_MODE_ALLOW_8X8``
>>> + - Transform size can be up to 8x8.
>>> + * - ``V4L2_VP9_TX_MODE_ALLOW_16X16``
>>> + - Transform size can be up to 16x16.
>>> + * - ``V4L2_VP9_TX_MODE_ALLOW_32X32``
>>> + - transform size can be up to 32x32.
>>> + * - ``V4L2_VP9_TX_MODE_SELECT``
>>> + - Bitstream contains transform size for each block.
>>> +
>>> +.. c:type:: v4l2_vp9_reference_mode
>>> +
>>> +.. cssclass:: longtable
>>> +
>>> +.. tabularcolumns:: |p{1.5cm}|p{6.3cm}|p{9.4cm}|
>>> +
>>> +.. flat-table:: enum v4l2_vp9_reference_mode
>>> + :header-rows: 0
>>> + :stub-columns: 0
>>> + :widths: 1 2
>>> +
>>> + * - ``V4L2_VP9_REF_MODE_SINGLE``
>>> + - Indicates that all the inter blocks use only a single reference frame
>>> + to generate motion compensated prediction.
>>> + * - ``V4L2_VP9_REF_MODE_COMPOUND``
>>> + - Requires all the inter blocks to use compound mode. Single reference
>>> + frame prediction is not allowed.
>>> + * - ``V4L2_VP9_REF_MODE_SELECT``
>>> + - Allows each individual inter block to select between single and
>>> + compound prediction modes.
>>> +
>>> +.. c:type:: v4l2_vp9_interpolation_filter
>>> +
>>> +.. cssclass:: longtable
>>> +
>>> +.. tabularcolumns:: |p{1.5cm}|p{6.3cm}|p{9.4cm}|
>>> +
>>> +.. flat-table:: enum v4l2_vp9_interpolation_filter
>>> + :header-rows: 0
>>> + :stub-columns: 0
>>> + :widths: 1 2
>>> +
>>> + * - ``V4L2_VP9_INTERP_FILTER_8TAP``
>>> + - Height tap filter.
>>> + * - ``V4L2_VP9_INTERP_FILTER_8TAP_SMOOTH``
>>> + - Height tap smooth filter.
>>> + * - ``V4L2_VP9_INTERP_FILTER_8TAP_SHARP``
>>> + - Height tap sharp filter.
>>> + * - ``V4L2_VP9_INTERP_FILTER_BILINEAR``
>>> + - Bilinear filter.
>>> + * - ``V4L2_VP9_INTERP_FILTER_SWITCHABLE``
>>> + - Filter selection is signaled at the block level.
>>> +
>>> +.. c:type:: v4l2_vp9_color_space
>>> +
>>> +.. cssclass:: longtable
>>> +
>>> +.. tabularcolumns:: |p{1.5cm}|p{6.3cm}|p{9.4cm}|
>>> +
>>> +.. flat-table:: enum v4l2_vp9_color_space
>>> + :header-rows: 0
>>> + :stub-columns: 0
>>> + :widths: 1 2
>>> +
>>> + * - ``V4L2_VP9_COLOR_SPACE_UNKNOWN``
>>> + - Unknown color space. In this case the color space must be signaled
>>> + outside the VP9 bitstream.
>>> + * - ``V4L2_VP9_COLOR_SPACE_BT_601``
>>> + - Rec. ITU-R BT.601-7 color space.
>>> + * - ``V4L2_VP9_COLOR_SPACE_BT_709``
>>> + - Rec. ITU-R BT.709-6 color space.
>>> + * - ``V4L2_VP9_COLOR_SPACE_SMPTE_170``
>>> + - SMPTE-170 color space.
>>> + * - ``V4L2_VP9_COLOR_SPACE_SMPTE_240``
>>> + - SMPTE-240 color space.
>>> + * - ``V4L2_VP9_COLOR_SPACE_BT_2020``
>>> + - Rec. ITU-R BT.2020-2 color space.
>>> + * - ``V4L2_VP9_COLOR_SPACE_RESERVED``
>>> + - Reserved. This value shall never be passed.
>>> + * - ``V4L2_VP9_COLOR_SPACE_SRGB``
>>> + - sRGB (IEC 61966-2-1) color space.
>>
>> Should this be here? We already have colorspace information in the pix format structs.
>>
>> It is also unclear from reading just this bit whether e.g. V4L2_VP9_COLOR_SPACE_SRGB
>> just describes the sRGB color primaries or also the transfer function and quantization
>> range.
>>
>> I'd like to see some more about how this is used. None of the other codec headers
>> have this.
>>
>
> I think this comes directly from the spec. The Rockchip VDEC doesn't
> seem to use it.
>
> Do you think we can drop it from here, and rely on the V4L2 colorspace
> passed in the format negotiation?
That would be preferred, yes. Otherwise you would have two places where you can
define colorspaces, and that's confusing.
>
>>> +
>>> +.. c:type:: v4l2_vp9_reset_frame_context
>>> +
>>> +.. cssclass:: longtable
>>> +
>>> +.. tabularcolumns:: |p{1.5cm}|p{6.3cm}|p{9.4cm}|
>>> +
>>> +.. flat-table:: enum v4l2_vp9_reset_frame_context
>>> + :header-rows: 0
>>> + :stub-columns: 0
>>> + :widths: 1 2
>>> +
>>> + * - ``V4L2_VP9_RESET_FRAME_CTX_NONE``
>>> + - Do not reset any frame context.
>>> + * - ``V4L2_VP9_RESET_FRAME_CTX_SPEC``
>>> + - Reset the frame context pointed by
>>> + :c:type:`v4l2_ctrl_vp9_frame_decode_params`.frame_context_idx.
>>> + * - ``V4L2_VP9_RESET_FRAME_CTX_ALL``
>>> + - Reset all frame contexts.
>>> +
>>> +.. c:type:: v4l2_vp9_intra_prediction_mode
>>> +
>>> +.. cssclass:: longtable
>>> +
>>> +.. tabularcolumns:: |p{1.5cm}|p{6.3cm}|p{9.4cm}|
>>> +
>>> +.. flat-table:: enum v4l2_vp9_intra_prediction_mode
>>> + :header-rows: 0
>>> + :stub-columns: 0
>>> + :widths: 1 2
>>> +
>>> + * - ``V4L2_VP9_INTRA_PRED_DC``
>>> + - DC intra prediction.
>>> + * - ``V4L2_VP9_INTRA_PRED_MODE_V``
>>> + - Vertical intra prediction.
>>> + * - ``V4L2_VP9_INTRA_PRED_MODE_H``
>>> + - Horizontal intra prediction.
>>> + * - ``V4L2_VP9_INTRA_PRED_MODE_D45``
>>> + - D45 intra prediction.
>>> + * - ``V4L2_VP9_INTRA_PRED_MODE_D135``
>>> + - D135 intra prediction.
>>> + * - ``V4L2_VP9_INTRA_PRED_MODE_D117``
>>> + - D117 intra prediction.
>>> + * - ``V4L2_VP9_INTRA_PRED_MODE_D153``
>>> + - D153 intra prediction.
>>> + * - ``V4L2_VP9_INTRA_PRED_MODE_D207``
>>> + - D207 intra prediction.
>>> + * - ``V4L2_VP9_INTRA_PRED_MODE_D63``
>>> + - D63 intra prediction.
>>> + * - ``V4L2_VP9_INTRA_PRED_MODE_TM``
>>> + - True motion intra prediction.
>>> +
>>> +.. c:type:: v4l2_vp9_segmentation
>>> +
>>> +.. cssclass:: longtable
>>> +
>>> +.. tabularcolumns:: |p{1.5cm}|p{6.3cm}|p{9.4cm}|
>>> +
>>> +.. flat-table:: struct v4l2_vp9_segmentation
>>> + :header-rows: 0
>>> + :stub-columns: 0
>>> + :widths: 1 1 2
>>> +
>>> + * - __u8
>>> + - ``flags``
>>> + - Combination of V4L2_VP9_SEGMENTATION_FLAG_* flags. See
>>> + :c:type:`v4l2_vp9_segmentation_flags`.
>>> + * - __u8
>>> + - ``tree_probs[7]``
>>> + - Specifies the probability values to be used when decoding segment_id.
>>
>> segment_id? Does this refer to a term defined in the VP9 spec?
>>
>
> Yes, this is all strictly spec compliant. segment_id and seg_id_predicted
> are VP9 syntax elements.
>
> In particular that description is copy-pasted from the spec, but
> I agree it may seem confusing in this context. How about:
>
> "to be used when decoding a Segment-ID"
That would be better, perhaps with a reference to the spec where this is
described.
>
>>> + * - __u8
>>> + - ``pred_prob[3]``
>>> + - Specifies the probability values to be used when decoding
>>> + seg_id_predicte.
>>
>> seg_id_predicte: typo? I don't see any field called seg_id_predicte.
>>
>> It looks like segment_id and seg_id_predicte are C field names, but I suspect
>> they are not. I think this should be clarified.
>>
>
> Ditto,
>
> "to be used when decoding a Predicted-Segment-ID"
>
> Maybe this will be clearer ?
Yes, and also with a reference if possible.
>
>
>>> + * - __u8
>>> + - ``padding[5]``
>>> + - Used to align this struct on 64 bit. Shall be filled with zeros.
>>
>> zeroes.
>>
>
> Oops, more typos :-)
>
> Thanks for reviewing,
> Ezequiel
>
Regards,
Hans
