Messages in this thread | | | Subject | Re: [PATCH v2 1/2] drm: bridge: dw-hdmi: Take input format from plat_data | From | Jose Abreu <> | Date | Mon, 6 Mar 2017 12:17:00 +0000 |
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Hi Neil,
On 06-03-2017 10:41, Neil Armstrong wrote: > On 03/03/2017 06:22 PM, Jose Abreu wrote: >> Hi Neil, >> >> >> On 03-03-2017 16:42, Neil Armstrong wrote: >>> Sure, I was meaning the *input* format the controller receives from the >>> pixel encoder, I'm quite sure the format is strict. >>> >> Hmm, not quite following you here. As far as the controller goes >> it supports the formats I mentioned: >> - 8/10/12/16 bits RGB 4:4:4 >> - 8/10/12/16 bits YCbCr 4:4:4 >> - 8/10/12 bits YCbCr 4:2:2 >> - 8/10/12/16 bits YCbCr 4:2:0 >> >> As for the CSC it supports RGB 4:4:4 to/from YCbCr 4:4:4 or 4:2:2 >> in every defined color depth. >> >> So, everything except 4:2:0 (I had to check documentation, I >> though that CSC supported less formats). >> >> Of course this is all limited by the implementation that HW team >> decides to choose. >> >> Best regards, >> Jose Miguel Abreu >> > Hi Jose, > > Thanks for the clarifications. > > I will try to add missing V4L formats > > - 8/10/12/16 bits RGB 4:4:4 > > MEDIA_BUS_FMT_RGB888_1X24 > MEDIA_BUS_FMT_RGB101010_1X30 (to be added) > MEDIA_BUS_FMT_RGB121212_1X36 (to be added) > MEDIA_BUS_FMT_RGB161616_1X48 (to be added) > > - 8/10/12/16 bits YCbCr 4:4:4 > > MEDIA_BUS_FMT_YUV8_1X24 > MEDIA_BUS_FMT_YUV10_1X30 > MEDIA_BUS_FMT_YUV12_1X36 (to be added) > MEDIA_BUS_FMT_YUV16_1X48 (to be added) > > - 8/10/12 bits YCbCr 4:2:2 > > MEDIA_BUS_FMT_UYVY8_1X16 > MEDIA_BUS_FMT_UYVY10_1X20 > MEDIA_BUS_FMT_UYVY12_1X24 > > - 8/10/12/16 bits YCbCr 4:2:0 > > Jose, how is supposed to be transmitted 4:2:0 over the controller ? > > Amlogic uses clock doubling to transmit 4:2:0 in CrYCb format. > > I assume, the transmission is in YYUYYV format in 2x clock.
Double rate or half rate? 4:2:0 requires half the bandwidth and the horizontal parameters are cut off by half also. I'm not very familiar with 4:2:0 but according to spec it shall be Cb[l][n] Y[l][n] Y[l][n+1] in one line and then Cr[l][n] Y[l+1][n] Y[l+1][n+1] in another line (where "l" is pixel line number and "n" is pixel number).
I've worked with 4:2:0 previously but it was just for a prof of concept (I never got to a point where I could submit anything standard), maybe someone who has worked with this can expand a little bit. Anyone?
> > So the formats should be (aligned on the MEDIA_BUS_FMT_YUYV8_1_5X8) : > > MEDIA_BUS_FMT_YUYV8_1_1X24 (to be added) > MEDIA_BUS_FMT_YUYV10_1_1X30 (to be added) > MEDIA_BUS_FMT_YUYV12_1_1X36 (to be added) > MEDIA_BUS_FMT_YUYV16_1_1X48 (to be added) > > to have the following transmissions scheme : > > uuuuuuuu/yyyyyyyy/yyyyyyyy > vvvvvvvv/yyyyyyyy/yyyyyyyy > > Can you confirm this ?
Seems fine, chroma in consecutive lines and luma in every line.
Best regards, Jose Miguel Abreu
> > Neil
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