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.

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.

Note:
This decoder is only guaranteed to decode JPEG files created using the SSP encoder.
Note that some JPEG files created with other software cannot be decoded.
Decoding often fails due to additional EXIF information.
When this happens, omit the EXIF information from the image .

See Also

SSPJpegDecoderErrorCode

Revision History

2009/09/17 Added a description of when JPEG files fail to decode.
2009/07/28 Revised the description of specifying options.
2009/06/23 Initial version.


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