rtjpeg.c File Reference

#include "libavutil/common.h"
#include "get_bits.h"
#include "rtjpeg.h"

Go to the source code of this file.

Macros
#define	PUT_COEFF(c)
#define	ALIGN(a)
	aligns the bitstream to the given power of two
#define	BLOCK(quant, dst, stride)

Functions
static int	get_block (GetBitContext *gb, int16_t *block, const uint8_t *scan, const uint32_t *quant)
	read one block from stream
int	ff_rtjpeg_decode_frame_yuv420 (RTJpegContext *c, AVFrame *f, const uint8_t *buf, int buf_size)
	decode one rtjpeg YUV420 frame
void	ff_rtjpeg_decode_init (RTJpegContext *c, DSPContext *dsp, int width, int height, const uint32_t *lquant, const uint32_t *cquant)
	initialize an RTJpegContext, may be called multiple times

Macro Definition Documentation

#define PUT_COEFF

(

c

)

Value:

i = scan[coeff--]; \
    block[i] = (c) * quant[i];

Definition at line 25 of file rtjpeg.c.

Referenced by get_block().

#define ALIGN

(

a

)

Value:

n = (-get_bits_count(gb)) & (a - 1); \
    if (n) {skip_bits(gb, n);}

aligns the bitstream to the given power of two

Definition at line 30 of file rtjpeg.c.

Referenced by get_block().

#define BLOCK	(		quant,
			dst,
			stride
	)

Value:

do { \
    int res = get_block(&gb, block, c->scan, quant); \
    if (res < 0) \
        return res; \
    if (res > 0) \
        c->dsp->idct_put(dst, stride, block); \
} while (0)

Referenced by ff_rtjpeg_decode_frame_yuv420().

Function Documentation

static int get_block ( GetBitContext *  gb, int16_t *  block, const uint8_t *  scan, const uint32_t *  quant  )

inlinestatic

read one block from stream

Parameters

gb	contains stream data
block	where data is written to
scan	array containing the mapping stream address -> block position
quant	quantization factors

Returns

0 means the block is not coded, < 0 means an error occurred.

Note: GetBitContext is used to make the code simpler, since all data is aligned this could be done faster in a different way, e.g. as it is done in MPlayer libmpcodecs/native/rtjpegn.c.

Definition at line 46 of file rtjpeg.c.

int ff_rtjpeg_decode_frame_yuv420	(	RTJpegContext *	c,
		AVFrame *	f,
		const uint8_t *	buf,
		int	buf_size
	)

decode one rtjpeg YUV420 frame

Parameters

c	context, must be initialized via ff_rtjpeg_decode_init
f	AVFrame to place decoded frame into. If parts of the frame are not coded they are left unchanged, so consider initializing it
buf	buffer containing input data
buf_size	length of input data in bytes

Returns

number of bytes consumed from the input buffer

Definition at line 106 of file rtjpeg.c.

Referenced by decode_frame().

void ff_rtjpeg_decode_init	(	RTJpegContext *	c,
		DSPContext *	dsp,
		int	width,
		int	height,
		const uint32_t *	lquant,
		const uint32_t *	cquant
	)

initialize an RTJpegContext, may be called multiple times

Parameters

c	context to initialize
dsp	specifies the idct to use for decoding
width	width of image, will be rounded down to the nearest multiple of 16 for decoding
height	height of image, will be rounded down to the nearest multiple of 16 for decoding
lquant	luma quantization table to use
cquant	chroma quantization table to use

Definition at line 156 of file rtjpeg.c.

Referenced by codec_reinit(), and decode_frame().