Re: [PATCH 1/2] v4l2-ctrl: Add decoder conceal color control
From: Stanimir Varbanov
Date: Thu Feb 25 2021 - 05:36:15 EST
On 2/16/21 10:58 AM, Hans Verkuil wrote:
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On 16/02/2021 09:56, Stanimir Varbanov wrote:
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> On 2/15/21 1:57 PM, Hans Verkuil wrote:
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>> On 15/02/2021 12:32, Stanimir Varbanov wrote:
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>>>
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>>>
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>>> On 2/9/21 1:05 PM, Hans Verkuil wrote:
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>>>> On 09/02/2021 10:45, Stanimir Varbanov wrote:
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>>>>> Add decoder v4l2 control to set conceal color.
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>>>>>
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>>>>> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@xxxxxxxxxx>
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>>>>> ---
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>>>>> .../media/v4l/ext-ctrls-codec.rst | 20 +++++++++++++++++++
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>>>>> drivers/media/v4l2-core/v4l2-ctrls.c | 9 +++++++++
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>>>>> include/uapi/linux/v4l2-controls.h | 1 +
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>>>>> 3 files changed, 30 insertions(+)
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>>>>>
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>>>>> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
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>>>>> index 00944e97d638..994650052333 100644
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>>>>> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
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>>>>> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
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>>>>> @@ -674,6 +674,26 @@ enum v4l2_mpeg_video_frame_skip_mode -
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>>>>> is currently displayed (decoded). This value is reset to 0 whenever
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>>>>> the decoder is started.
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>>>>>
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>>>>> +``V4L2_CID_MPEG_VIDEO_DEC_CONCEAL_COLOR (integer64)``
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>>>>> + This control sets conceal color in YUV color space. It describes the
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>>>>> + client preference of error conceal color in case of error where
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>>>>> + reference frame is missing. The decoder would paint the reference
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>>>>> + buffer with preferred color and use it for future decoding.
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>>>>> + Applicable to decoders.
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>>>>
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>>>> You should mention explicitly that this is using 16-bit color components
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>>>> and expects Limited Range.
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>>>
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>>> I don't want to limit the client to Limited range only. I'll mention in
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>>> the description that both ranges are valid.
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>>
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>> OK, but then you need to describe what the color format depends on. See more
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>> below.
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>>>
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>>>>
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>>>>> +
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>>>>> +.. flat-table::
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>>>>> + :header-rows: 0
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>>>>> + :stub-columns: 0
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>>>>> +
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>>>>> + * - Bit 0:15
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>>>>> + - Y luminance
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>>>>> + * - Bit 16:31
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>>>>> + - Cb chrominance
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>>>>> + * - Bit 32:47
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>>>>> + - Cr chrominance
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>>>>> + * - Bit 48:63
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>>>>> + - Must be zero
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>>>>> +
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> The table how the bits are spread into int64.
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>>>>> ``V4L2_CID_MPEG_VIDEO_DECODER_SLICE_INTERFACE (boolean)``
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>>>>> If enabled the decoder expects to receive a single slice per buffer,
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>>>>> otherwise the decoder expects a single frame in per buffer.
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>>>>> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
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>>>>> index 016cf6204cbb..a3b9d28a00b7 100644
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>>>>> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
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>>>>> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
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>>>>> @@ -945,6 +945,7 @@ const char *v4l2_ctrl_get_name(u32 id)
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>>>>> case V4L2_CID_MPEG_VIDEO_VBV_SIZE: return "VBV Buffer Size";
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>>>>> case V4L2_CID_MPEG_VIDEO_DEC_PTS: return "Video Decoder PTS";
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>>>>> case V4L2_CID_MPEG_VIDEO_DEC_FRAME: return "Video Decoder Frame Count";
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>>>>> + case V4L2_CID_MPEG_VIDEO_DEC_CONCEAL_COLOR: return "Video Decoder Conceal Color";
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>>>>> case V4L2_CID_MPEG_VIDEO_VBV_DELAY: return "Initial Delay for VBV Control";
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>>>>> case V4L2_CID_MPEG_VIDEO_MV_H_SEARCH_RANGE: return "Horizontal MV Search Range";
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>>>>> case V4L2_CID_MPEG_VIDEO_MV_V_SEARCH_RANGE: return "Vertical MV Search Range";
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>>>>> @@ -1430,6 +1431,14 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
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>>>>> *max = 0x7fffffffffffffffLL;
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>>>>> *step = 1;
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>>>>> break;
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>>>>> + case V4L2_CID_MPEG_VIDEO_DEC_CONCEAL_COLOR:
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>>>>> + *type = V4L2_CTRL_TYPE_INTEGER64;
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>>>>> + *min = 0;
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>>>>> + /* default for 8bit black, luma is 16, chroma is 128 */
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>>>>
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>>>> Since this is 16 bit the actual default luma value for black is 4096 and for chroma use
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>>>> 32768 (i.e. both values are times 256).
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>>>
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>>> If we follow this for pixel format with 10bit per channel we have to
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>>> multiply by 64?
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>>
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>> No, you multiply by 4. 12 bit depth will multiple by 16, and 16 bit depth by 256.
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>>
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>> But how do you format this? Using bits 29-0? Or use 9-0 for one color component,
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>> 25-16 for another and 41-32 for the last component?
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> I described this in the table above:
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> Bit 0:15 - Y luminance
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> Bit 16:31 - Cb chrominance
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> Bit 32:47 - Cr chrominance
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> Bit 48:63 - Must be zero
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> So depending on the bit depth of the current pixel format:
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> 8bit - 0:7 Y', 16:23 Cb, 32:39 Cr
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> 10bit - 0:9 Y', 16:25 Cb, 32:41 Cr
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> 12bit - 0:11 Y', 16:27 Cb, 32:43 Cr
^^^^
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Apologies, I missed that table!
Hans, do you want me to update with the above ^^^^ components bits or
something else?
--
regards,
Stan