BT656 - 16bits interface

Hi Sujith,

Thanks for returning with reply.In the vps_capture you refered there is the following typedef, and in remarks it it said 8 bits-BT656, 16 bits-BT1120.
Therefore I asked in the root post if it is legal to use 16 bits for bt656, because theretically it is allowed, but perephs there is some limitation in DM8168.
It seems that the remarks point to such limitation.

Thanks,

Ran

typedef enum
{
    VPS_CAPT_VIDEO_IF_MODE_8BIT = 0,
    /**< Embedded sync mode:  8bit - BT656 standard  */
    VPS_CAPT_VIDEO_IF_MODE_16BIT,
    /**< Embedded sync mode:  16bit - BT1120 standard  */
    VPS_CAPT_VIDEO_IF_MODE_24BIT,
    /**< Embedded sync mode:  24bit */
    VPS_CAPT_VIDEO_IF_MODE_MAX
    /**< Maximum modes */
} Vps_CaptVideoIfMode;

Hi Ran,

As such, as per BT1120 specs, sync code should be present on both the channels,  So if you have sync code present on one of the channels, VIP will be able to detect the sync code. In VIp, we could select the channel on which sync codes are present.

Also could you see if this is what you are looking for?

Thanks,

Brijesh Jadav

Hi Brijesh, Sujith,

Thank you very much for the answers, So I understand from this that as long as the input is legal bt656, with sync words, the HW will handle it correct also when using 16 bit interface, right ?
What module is responsible for processing BT656 sync words (or BT1120 sync words): Is it HDVPSS driver or the VIP hardware ?

Thanks,

Ran

Hi Sujith,

Can you please verify that I can configure VIP port as 16 bits interface instead of 8 bits interface, and VIP will detect the BT656 video (without any other configuration required). 

Thanks,

Ran

Hi,

But why cant you configure as 8-bit only if your input is 8-bit. Any reason for configuring as 16-bit instead of 8-bit.

Hi,

Basically, I intend to use one of the port, say VIP0 as a single channel, 16-bits interface: Some input resolutions will use BT656 16-bit interface , and for other resolution BT1120 16-bits interface (BT656 & BT1120  are intended for different resolutions according to spec).
Also according to BT656 and BT1120 specs they are used as 8 or 10 bits/pixel word. As I understand from Netra datasheet, 16 bits interface (described in VIP chapter) can be used as described in VIP chapter: 

FIGURE 2-8 in data sheet:

8 bits 8 bits

Y0       CB0

Y1       CR1

Y2       CB2

So it seems from datasheet that both BT656 and BT1120 can be used with 16 bits interface for single channel, and using all 16 bits in this interface.

Is there some limitation with BT656 so that it can be used only as 8 bits interface ?

As I understand, there is no configuration parameter in capture driver which says if its BT656 sync or BT1120 sync , the only configuration is of bits interface length 8/16/24. Does it mean that the VIP hardware detects the sync word format by itself and process the sync data according to the detected format (BT656/BT1120) ?

Thank you very much for your time,

Ran