libavcodec/rtjpeg.c File Reference

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

Go to the source code of this file.

Defines
#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, DCTELEM *block, const uint8_t *scan, const uint32_t *quant)
	read one block from stream
int	rtjpeg_decode_frame_yuv420 (RTJpegContext *c, AVFrame *f, const uint8_t *buf, int buf_size)
	decode one rtjpeg YUV420 frame
void	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

---

Define Documentation

#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 31 of file rtjpeg.c.

Referenced by av_malloc(), and 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 config(), filter(), rtjpeg_decode_frame_yuv420(), and uninit().

#define PUT_COEFF

(

c

)

Value:

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

Definition at line 26 of file rtjpeg.c.

Referenced by get_block().

---

Function Documentation

static int get_block	(	GetBitContext *	gb,
		DCTELEM *	block,
		const uint8_t *	scan,
		const uint32_t *	quant
	)			[inline, static]

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 47 of file rtjpeg.c.

int 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 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 107 of file rtjpeg.c.

Referenced by decode_frame().

void 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 157 of file rtjpeg.c.

Referenced by codec_reinit(), and decode_frame().