libavcodec/adpcmenc.c File Reference

ADPCM encoders First version by Francois Revol (revol@free.fr) Fringe ADPCM codecs (e.g., DK3, DK4, Westwood) by Mike Melanson (melanson@pcisys.net). More...

#include "avcodec.h"
#include "get_bits.h"
#include "put_bits.h"
#include "bytestream.h"
#include "adpcm.h"
#include "adpcm_data.h"

Go to the source code of this file.

Data Structures
struct	TrellisPath
struct	TrellisNode
struct	ADPCMEncodeContext
Defines
#define	FREEZE_INTERVAL   128
#define	STORE_NODE(NAME, STEP_INDEX)
#define	LOOP_NODES(NAME, STEP_TABLE, STEP_INDEX)
#define	ADPCM_ENCODER(id_, name_, long_name_)
Functions
static av_cold int	adpcm_encode_init (AVCodecContext *avctx)
static av_cold int	adpcm_encode_close (AVCodecContext *avctx)
static unsigned char	adpcm_ima_compress_sample (ADPCMChannelStatus *c, short sample)
static unsigned char	adpcm_ima_qt_compress_sample (ADPCMChannelStatus *c, short sample)
static unsigned char	adpcm_ms_compress_sample (ADPCMChannelStatus *c, short sample)
static unsigned char	adpcm_yamaha_compress_sample (ADPCMChannelStatus *c, short sample)
static void	adpcm_compress_trellis (AVCodecContext *avctx, const short *samples, uint8_t *dst, ADPCMChannelStatus *c, int n)
static int	adpcm_encode_frame (AVCodecContext *avctx, unsigned char *frame, int buf_size, void *data)
	ADPCM_ENCODER (CODEC_ID_ADPCM_IMA_QT, adpcm_ima_qt,"ADPCM IMA QuickTime")
	ADPCM_ENCODER (CODEC_ID_ADPCM_IMA_WAV, adpcm_ima_wav,"ADPCM IMA WAV")
	ADPCM_ENCODER (CODEC_ID_ADPCM_MS, adpcm_ms,"ADPCM Microsoft")
	ADPCM_ENCODER (CODEC_ID_ADPCM_SWF, adpcm_swf,"ADPCM Shockwave Flash")
	ADPCM_ENCODER (CODEC_ID_ADPCM_YAMAHA, adpcm_yamaha,"ADPCM Yamaha")

---

Detailed Description

ADPCM encoders First version by Francois Revol (revol@free.fr) Fringe ADPCM codecs (e.g., DK3, DK4, Westwood) by Mike Melanson (melanson@pcisys.net).

See ADPCM decoder reference documents for codec information.

Definition in file adpcmenc.c.

---

Define Documentation

#define ADPCM_ENCODER	(	id_,
		name_,
		long_name_		)

Value:

AVCodec ff_ ## name_ ## _encoder = {                        \
    .name           = #name_,                               \
    .type           = AVMEDIA_TYPE_AUDIO,                   \
    .id             = id_,                                  \
    .priv_data_size = sizeof(ADPCMEncodeContext),           \
    .init           = adpcm_encode_init,                    \
    .encode         = adpcm_encode_frame,                   \
    .close          = adpcm_encode_close,                   \
    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16,   \
                                                      AV_SAMPLE_FMT_NONE}, \
    .long_name      = NULL_IF_CONFIG_SMALL(long_name_),     \
}

Definition at line 687 of file adpcmenc.c.

#define FREEZE_INTERVAL   128

Definition at line 59 of file adpcmenc.c.

Referenced by adpcm_compress_trellis(), adpcm_encode_init(), g722_encode_init(), and g722_encode_trellis().

#define LOOP_NODES	(	NAME,
		STEP_TABLE,
		STEP_INDEX		)

Value:

const int predictor = nodes[j]->sample1;\
                const int div = (sample - predictor) * 4 / STEP_TABLE;\
                int nmin = av_clip(div - range, -7, 6);\
                int nmax = av_clip(div + range, -6, 7);\
                if (nmin <= 0)\
                    nmin--; /* distinguish -0 from +0 */\
                if (nmax < 0)\
                    nmax--;\
                for (nidx = nmin; nidx <= nmax; nidx++) {\
                    const int nibble = nidx < 0 ? 7 - nidx : nidx;\
                    int dec_sample = predictor +\
                                    (STEP_TABLE *\
                                     ff_adpcm_yamaha_difflookup[nibble]) / 8;\
                    STORE_NODE(NAME, STEP_INDEX);\
                }

Referenced by adpcm_compress_trellis().

#define STORE_NODE	(	NAME,
		STEP_INDEX		)

Referenced by adpcm_compress_trellis(), and g722_encode_trellis().

---

Function Documentation

static void adpcm_compress_trellis	(	AVCodecContext *	avctx,
		const short *	samples,
		uint8_t *	dst,
		ADPCMChannelStatus *	c,
		int	n
	)			[static]

Definition at line 265 of file adpcmenc.c.

static av_cold int adpcm_encode_close

(

AVCodecContext *

avctx

)

[static]

Definition at line 151 of file adpcmenc.c.

static int adpcm_encode_frame	(	AVCodecContext *	avctx,
		unsigned char *	frame,
		int	buf_size,
		void *	data
	)			[static]

Definition at line 455 of file adpcmenc.c.

static av_cold int adpcm_encode_init

(

AVCodecContext *

avctx

)

[static]

Definition at line 61 of file adpcmenc.c.

ADPCM_ENCODER	(	CODEC_ID_ADPCM_YAMAHA	,
		adpcm_yamaha	,
		"ADPCM Yamaha"
	)

ADPCM_ENCODER	(	CODEC_ID_ADPCM_SWF	,
		adpcm_swf	,
		"ADPCM Shockwave Flash"
	)

ADPCM_ENCODER	(	CODEC_ID_ADPCM_MS	,
		adpcm_ms	,
		"ADPCM Microsoft"
	)

ADPCM_ENCODER	(	CODEC_ID_ADPCM_IMA_WAV	,
		adpcm_ima_wav	,
		"ADPCM IMA WAV"
	)

ADPCM_ENCODER	(	CODEC_ID_ADPCM_IMA_QT	,
		adpcm_ima_qt	,
		"ADPCM IMA QuickTime"
	)

static unsigned char adpcm_ima_compress_sample	(	ADPCMChannelStatus *	c,
		short	sample
	)			[inline, static]

Definition at line 164 of file adpcmenc.c.

static unsigned char adpcm_ima_qt_compress_sample	(	ADPCMChannelStatus *	c,
		short	sample
	)			[inline, static]

Definition at line 177 of file adpcmenc.c.

static unsigned char adpcm_ms_compress_sample	(	ADPCMChannelStatus *	c,
		short	sample
	)			[inline, static]

Definition at line 214 of file adpcmenc.c.

static unsigned char adpcm_yamaha_compress_sample	(	ADPCMChannelStatus *	c,
		short	sample
	)			[inline, static]

Definition at line 243 of file adpcmenc.c.