hi_mpi_vo_set_chn_attr
Applicability
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Description
Sets the attributes of a specified VO channel.
Prototype
hi_s32 hi_mpi_vo_set_chn_attr(hi_vo_layer layer, hi_vo_chn chn, const hi_vo_chn_attr *chn_attr)
Parameters
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Parameter |
Input/Output |
Description |
|---|---|---|
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layer |
Input |
VO layer ID. Value range: [0, 9) Graphics layers and cascade video layers are not supported. |
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chn |
Input |
VO channel ID. Value range: [0, 64) |
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chn_attr |
Input |
Pointer to the attributes of a video channel. |
Returns
- 0: success
- Other values: failure. For details, see VO Return Codes.
Restrictions
- The size of the channel display region cannot exceed the canvas size img_size (one of video layer attributes).
- This API can be dynamically configured. That is, you can call it when a VO device is enabled and the corresponding video layer is configured.
- The channel attribute rect of the device must be a multiple of 2, and the width and height must be greater than or equal to 32. It is recommended that the vertical coordinate of the start point be a multiple of 4. Otherwise, unexpected image quality issues may occur.
- If the video layer of a device is zoomed in, the start position, width, and height defined in the rect attribute are the values before the video layer is zoomed in. After the video layer is zoomed in, the start position shifts, and the width and height may increase by ratio.
- Currently, this API does not support multiple processes.
Parent topic: VO