GI.GstVideo.Structs.VideoFrame

A video frame obtained from videoFrameMap

Exported types

newtype VideoFrame

Memory-managed wrapper type.

Constructors

VideoFrame (ManagedPtr VideoFrame)

Instances

Eq VideoFrame

Defined in GI.GstVideo.Structs.VideoFrame

Methods

(==) :: VideoFrame -> VideoFrame -> Bool

(/=) :: VideoFrame -> VideoFrame -> Bool

BoxedPtr VideoFrame

Defined in GI.GstVideo.Structs.VideoFrame

Methods

boxedPtrCopy :: VideoFrame -> IO VideoFrame

boxedPtrFree :: VideoFrame -> IO ()

CallocPtr VideoFrame

Defined in GI.GstVideo.Structs.VideoFrame

Methods

boxedPtrCalloc :: IO (Ptr VideoFrame)

ManagedPtrNewtype VideoFrame

Defined in GI.GstVideo.Structs.VideoFrame

Methods

toManagedPtr :: VideoFrame -> ManagedPtr VideoFrame

tag ~ 'AttrSet => Constructible VideoFrame tag

Defined in GI.GstVideo.Structs.VideoFrame

Methods

new :: MonadIO m => (ManagedPtr VideoFrame -> VideoFrame) -> [AttrOp VideoFrame tag] -> m VideoFrame

newZeroVideoFrame :: MonadIO m => m VideoFrame

Construct a VideoFrame struct initialized to zero.

Methods

Click to display all available methods, including inherited ones

Methods

copy, copyPlane, unmap.

Getters

None.

Setters

None.

copy

videoFrameCopy

Arguments

:: (HasCallStack, MonadIO m)

=> VideoFrame

dest: a VideoFrame

-> VideoFrame

src: a VideoFrame

-> m Bool

Returns: TRUE if the contents could be copied.

Copy the contents from src to dest.

Note: Since: 1.18, dest dimensions are allowed to be smaller than src dimensions.

copyPlane

videoFrameCopyPlane

Arguments

:: (HasCallStack, MonadIO m)

=> VideoFrame

dest: a VideoFrame

-> VideoFrame

src: a VideoFrame

-> Word32

plane: a plane

-> m Bool

Returns: TRUE if the contents could be copied.

Copy the plane with index plane from src to dest.

Note: Since: 1.18, dest dimensions are allowed to be smaller than src dimensions.

map

videoFrameMap

Arguments

:: (HasCallStack, MonadIO m)

=> VideoInfo

info: a VideoInfo

-> Buffer

buffer: the buffer to map

-> [MapFlags]

flags: MapFlags

-> m (Bool, VideoFrame)

Returns: True on success.

Use info and buffer to fill in the values of frame. frame is usually allocated on the stack, and you will pass the address to the VideoFrame structure allocated on the stack; videoFrameMap will then fill in the structures with the various video-specific information you need to access the pixels of the video buffer. You can then use accessor macros such as GST_VIDEO_FRAME_COMP_DATA(), GST_VIDEO_FRAME_PLANE_DATA(), GST_VIDEO_FRAME_COMP_STRIDE(), GST_VIDEO_FRAME_PLANE_STRIDE() etc. to get to the pixels.

C code

 GstVideoFrame vframe;
 ...
 // set RGB pixels to black one at a time
 if (gst_video_frame_map (&vframe, video_info, video_buffer, GST_MAP_WRITE)) {
   guint8 *pixels = GST_VIDEO_FRAME_PLANE_DATA (vframe, 0);
   guint stride = GST_VIDEO_FRAME_PLANE_STRIDE (vframe, 0);
   guint pixel_stride = GST_VIDEO_FRAME_COMP_PSTRIDE (vframe, 0);

   for (h = 0; h < height; ++h) {
     for (w = 0; w < width; ++w) {
       guint8 *pixel = pixels + h * stride + w * pixel_stride;

       memset (pixel, 0, pixel_stride);
     }
   }

   gst_video_frame_unmap (&vframe);
 }
 ...

All video planes of buffer will be mapped and the pointers will be set in frame->data.

The purpose of this function is to make it easy for you to get to the video pixels in a generic way, without you having to worry too much about details such as whether the video data is allocated in one contiguous memory chunk or multiple memory chunks (e.g. one for each plane); or if custom strides and custom plane offsets are used or not (as signalled by GstVideoMeta on each buffer). This function will just fill the VideoFrame structure with the right values and if you use the accessor macros everything will just work and you can access the data easily. It also maps the underlying memory chunks for you.

mapId

videoFrameMapId

Arguments

:: (HasCallStack, MonadIO m)

=> VideoInfo

info: a VideoInfo

-> Buffer

buffer: the buffer to map

-> Int32

id: the frame id to map

-> [MapFlags]

flags: MapFlags

-> m (Bool, VideoFrame)

Returns: True on success.

Use info and buffer to fill in the values of frame with the video frame information of frame id.

When id is -1, the default frame is mapped. When id != -1, this function will return False when there is no GstVideoMeta with that id.

All video planes of buffer will be mapped and the pointers will be set in frame->data.

unmap

videoFrameUnmap

Arguments

:: (HasCallStack, MonadIO m)

=> VideoFrame

frame: a VideoFrame

-> m ()

Unmap the memory previously mapped with gst_video_frame_map.

Properties

buffer

the mapped buffer

clearVideoFrameBuffer :: MonadIO m => VideoFrame -> m ()

Set the value of the “buffer” field to Nothing. When overloading is enabled, this is equivalent to

clear #buffer

getVideoFrameBuffer :: MonadIO m => VideoFrame -> m (Maybe Buffer)

Get the value of the “buffer” field. When overloading is enabled, this is equivalent to

get videoFrame #buffer

setVideoFrameBuffer :: MonadIO m => VideoFrame -> Ptr Buffer -> m ()

Set the value of the “buffer” field. When overloading is enabled, this is equivalent to

set videoFrame [ #buffer := value ]

flags

VideoFrameFlags for the frame

getVideoFrameFlags :: MonadIO m => VideoFrame -> m [VideoFrameFlags]

Get the value of the “flags” field. When overloading is enabled, this is equivalent to

get videoFrame #flags

setVideoFrameFlags :: MonadIO m => VideoFrame -> [VideoFrameFlags] -> m ()

Set the value of the “flags” field. When overloading is enabled, this is equivalent to

set videoFrame [ #flags := value ]

id

id of the mapped frame. the id can for example be used to identify the frame in case of multiview video.

getVideoFrameId :: MonadIO m => VideoFrame -> m Int32

Get the value of the “id” field. When overloading is enabled, this is equivalent to

get videoFrame #id

setVideoFrameId :: MonadIO m => VideoFrame -> Int32 -> m ()

Set the value of the “id” field. When overloading is enabled, this is equivalent to

set videoFrame [ #id := value ]

info

the VideoInfo

getVideoFrameInfo :: MonadIO m => VideoFrame -> m VideoInfo

Get the value of the “info” field. When overloading is enabled, this is equivalent to

get videoFrame #info

meta

pointer to metadata if any

clearVideoFrameMeta :: MonadIO m => VideoFrame -> m ()

Set the value of the “meta” field to Nothing. When overloading is enabled, this is equivalent to

clear #meta

getVideoFrameMeta :: MonadIO m => VideoFrame -> m (Ptr ())

Get the value of the “meta” field. When overloading is enabled, this is equivalent to

get videoFrame #meta

setVideoFrameMeta :: MonadIO m => VideoFrame -> Ptr () -> m ()

Set the value of the “meta” field. When overloading is enabled, this is equivalent to

set videoFrame [ #meta := value ]