SSP_StartJpegDecoderFast

Syntax


BOOL SSP_StartJpegDecoderFast(SSPJpegDecoderFastContext* pCtx, u8* data, u32 size, void* dst, u32 maxWidth, u32 maxHeight, u32 option);

Arguments

pCtx	Context structure. Must have 4-byte alignment.
data	JPEG file to decode.
size	Size of the JPEG file to decode.
dst	Buffer used to store a decoded image. A buffer of the size width * height * 2 is required; and it must have 4-byte alignment.
maxWidth	Maximum width allowed (in pixels) for the image to decode. When decoding has finished, the width of the image decoded in pCtx->`width` is stored here.
maxHeight	Maximum height allowed (in pixels) for the image to decode. When decoding has finished, the height of the image decoded in pCtx->`height` is stored here.
option	Decoding options (`SSP_JPEG_RGB555`, `SSP_JPEG_THUMBNAIL`). You must always specify `SSP_JPEG_RGB555`.

Return Values

If successful, returns TRUE.
If failed, an error code of the SSPJpegDecoderErrorCode type is stored in pCtx->errorCode.

Description

Decodes a JPEG file into RGB555 image data. JPEG files can be decoded only from the YUV420, YUV422, and YUV444 formats.
This function decodes images faster than the SSP_StartJpegDecoder function, but the image must be a multiple of either 8 pixels or 16 pixels.
There are also several differences from the SSP_StartJpegDecoder function.

You must pass the work buffer as pCtx. Because the context structure is large, do not allocate a region from the stack like local variables.
The vertical and horizontal sizes of the decoded image are returned replaced by the members of the context structure. Get these from the pCtx->width and pCtx->height.
You must specify SSP_JPEG_RGB555 for the decoding option.

If SSP_JPEG_THUMBNAIL is also specified for option, this function decodes a thumbnail image. If only SSP_JPEG_RGB555 is specified, it decodes the main image.

Revision History

2009/07/28 Revised the explanation of option specifications.
2009/06/23 Initial version.