adpcmenc.c File Reference

ADPCM encoders See ADPCM decoder reference documents for codec information. More...

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

Classes
struct	TrellisPath
struct	TrellisNode
struct	ADPCMEncodeContext

Macros
#define	FREEZE_INTERVAL   128
#define	STORE_NODE(NAME, STEP_INDEX)
#define	LOOP_NODES(NAME, STEP_TABLE, STEP_INDEX)
#define	ADPCM_ENCODER(id_, name_, sample_fmts_, long_name_)

Typedefs
typedef struct TrellisPath	TrellisPath
typedef struct TrellisNode	TrellisNode
typedef struct ADPCMEncodeContext	ADPCMEncodeContext

Functions
	ADPCM_ENCODER (AV_CODEC_ID_ADPCM_IMA_QT, adpcm_ima_qt, sample_fmts_p, "ADPCM IMA QuickTime")
	ADPCM_ENCODER (AV_CODEC_ID_ADPCM_IMA_WAV, adpcm_ima_wav, sample_fmts_p, "ADPCM IMA WAV")
	ADPCM_ENCODER (AV_CODEC_ID_ADPCM_MS, adpcm_ms, sample_fmts, "ADPCM Microsoft")
	ADPCM_ENCODER (AV_CODEC_ID_ADPCM_SWF, adpcm_swf, sample_fmts, "ADPCM Shockwave Flash")
	ADPCM_ENCODER (AV_CODEC_ID_ADPCM_YAMAHA, adpcm_yamaha, sample_fmts, "ADPCM Yamaha")

Detailed Description

ADPCM encoders See ADPCM decoder reference documents for codec information.

Macro Definition Documentation

ADPCM_ENCODER

#define ADPCM_ENCODER	(		id_,
			name_,
			sample_fmts_,
			long_name_
	)

Value:

AVCodec ff_ ## name_ ## _encoder = {                        \
    .name           = #name_,                               \
    .long_name      = NULL_IF_CONFIG_SMALL(long_name_),     \
    .type           = AVMEDIA_TYPE_AUDIO,                   \
    .id             = id_,                                  \
    .priv_data_size = sizeof(ADPCMEncodeContext),           \
    .init           = adpcm_encode_init,                    \
    .encode2        = adpcm_encode_frame,                   \
    .close          = adpcm_encode_close,                   \
    .sample_fmts    = sample_fmts_,                         \
}

LOOP_NODES

#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);\
                }