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disp_vcap_channel_props_t

Configurable properties of a video capture unit

Synopsis:

typedef struct {
    unsigned    size;
    unsigned    flags;
    unsigned    video_source;
    unsigned    audio_source;
    unsigned    input_format;
    unsigned    output_format;
    int         tuner_channel;
    int         Fif;
    short       dst_width;
    short       dst_height;
    short       crop_top;
    short       crop_bottom;
    short       crop_left;
    short       crop_right; 
    short       brightness;
    short       contrast;
    short       u_saturation;
    short       v_saturation;
    short       hue;
    short       reserved;
    unsigned    update_flags;
    int         scaler_index;
    unsigned    reserved2[6];
} disp_vcap_channel_props_t;

Description:

The disp_vcap_channel_props_t describes the configurable properties of a video capture unit. The members include:

size

Filled in with sizeof (disp_vcap_channel_props_t) on instantiation.

flags

Valid flags are:

• DISP_VCAP_FLAG_AFT_ON -- enable Auto Fine Tuning. After the driver programs the TV tuner to the requested frequency and band, the driver can use feedback from the tuner hardware in order to adjust the frequency to improve signal quality.
• DISP_VCAP_FLAG_RUNNING -- the driver should enable streaming of incoming video frames only if this flag is set.
• DISP_VCAP_FLAG_DOUBLE_BUFFER -- enable double buffering of the incoming video frames. The driver should direct each alternate frame of data to the alternate memory buffer.
• DISP_VCAP_FLAG_SYNC_WITH_SCALER -- valid when DISP_VCAP_FLAG_DOUBLE_BUFFER is also specified. The driver should attempt to configure the hardware such that whenever a complete frame of data arrives, the scaler is automatically set to display the new frame.

  Note that the scaler hardware is already configured up when the set_channel_props() function defined in the disp_vcapfuncs_t structure is called. If the driver can't synchronize the capture unit with the scaler specified by the scaler_index member of the disp_vcap_channel_props_t structure in this manner, this function should simply act as if this flag hadn't been specified.

video_source

The source of the video signal to be captured:

• DISP_VCAP_SOURCE_TUNER -- capture from the output of the TV tuner.
• DISP_VCAP_SOURCE_SVIDEO -- capture from the SVideo connector.
• DISP_VCAP_SOURCE_COMPOSITE -- capture from the Composite video connector.

If something other than one of the above is specified, the driver should default to something reasonable.

audio_source

The source of the audio signal that's routed through the capture unit:

• DISP_VCAP_AUDIO_SOURCE_MUTE -- mute the audio output from the capture unit.
• DISP_VCAP_AUDIO_SOURCE_TUNER -- route the audio signal from the TV tuner through the capture unit.
• DISP_VCAP_AUDIO_SOURCE_EXTERNAL -- route the audio signal from the external line in through the capture unit.

input_format

The encoding of the incoming signal to be captured:

• DISP_TV_SIGNAL_NTSC
• DISP_TV_SIGNAL_NTSC_JAPAN
• DISP_TV_SIGNAL_PAL
• DISP_TV_SIGNAL_PAL_M
• DISP_TV_SIGNAL_PAL_N
• DISP_TV_SIGNAL_PAL_N_COMBO
• DISP_TV_SIGNAL_SECAM

output_format

The format of the data output by the capture unit; see "Pixel formats" in the Writing a Graphics Driver chapter.

tuner_channel

The tuner frequency, in Hertz, to which the TV tuner should be programmed.

Fif

The Intermediate Frequency, in Hertz, to be used when programming the TV tuner.

dst_width

The output width of the frames after scaling.

dst_height

The output height of the frames after scaling.

crop_top

The number of lines to crop off the top of the captured before scaling.

crop_bottom

The number of lines to crop off the bottom of the captured before scaling.

crop_left

The number of lines to crop off the left of the captured before scaling.

crop_right

The number of lines to crop off the right of the captured before scaling.

brightness

The luminance adjustment to captured video. This is a signed value, where 0 means no adjustment, 32767 is the maximum brightness, and -32768 is the darkest.

contrast

The contrast adjustment to captured video. This is a signed value, where 0 means normal contrast, 32767 is the maximum contrast, and -32768 is the minimum.

u_saturation

The saturation level of the Cr chroma component of captured video. This is a signed value, where 0 means normal saturation, 32767 is the maximum saturation, and -32768 is the minimum.

v_saturation

The saturation level of the Cb chroma component of captured video. This is a signed value, where 0 means normal saturation, 32767 is the maximum saturation, and -32768 is the minimum.

hue

The level of green hue adjustment to captured video. This is a signed value, where 0 means no adjustment, 32767 is the maximum hue, and -32768 is the minimum.

update_flags

Flags that indicate which members of the disp_vcap_channel_props_t structure contain valid data that should be used to program the capture unit:

Classification:

Photon

See also:

disp_vcapfuncs_t