dpcm.c File Reference

#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "bytestream.h"
#include "internal.h"
#include "mathops.h"

Go to the source code of this file.

Data Structures
struct	DPCMContext

Macros
#define	DPCM_DECODER(id_, name_, long_name_)

Functions
static av_cold int	dpcm_decode_init (AVCodecContext *avctx)
static int	dpcm_decode_frame (AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
	DPCM_DECODER (AV_CODEC_ID_DERF_DPCM, derf_dpcm, "DPCM Xilam DERF")
	DPCM_DECODER (AV_CODEC_ID_GREMLIN_DPCM, gremlin_dpcm, "DPCM Gremlin")
	DPCM_DECODER (AV_CODEC_ID_INTERPLAY_DPCM, interplay_dpcm, "DPCM Interplay")
	DPCM_DECODER (AV_CODEC_ID_ROQ_DPCM, roq_dpcm, "DPCM id RoQ")
	DPCM_DECODER (AV_CODEC_ID_SDX2_DPCM, sdx2_dpcm, "DPCM Squareroot-Delta-Exact")
	DPCM_DECODER (AV_CODEC_ID_SOL_DPCM, sol_dpcm, "DPCM Sol")
	DPCM_DECODER (AV_CODEC_ID_XAN_DPCM, xan_dpcm, "DPCM Xan")

Variables
static const int32_t	derf_steps [96]
static const int16_t	interplay_delta_table []
static const int8_t	sol_table_old [16]
static const int8_t	sol_table_new [16]
static const int16_t	sol_table_16 [128]

Detailed Description

Assorted DPCM (differential pulse code modulation) audio codecs by Mike Melanson (melan.nosp@m.son@.nosp@m.pcisy.nosp@m.s.ne.nosp@m.t) Xan DPCM decoder by Mario Brito (mbrit.nosp@m.o@st.nosp@m.udent.nosp@m..dei.nosp@m..uc.p.nosp@m.t) for more information on the specific data formats, visit: http://www.pcisys.net/~melanson/codecs/simpleaudio.html SOL DPCMs implemented by Konstantin Shishkov

Note about using the Xan DPCM decoder: Xan DPCM is used in AVI files found in the Wing Commander IV computer game. These AVI files contain WAVEFORMAT headers which report the audio format as 0x01: raw PCM. Clearly incorrect. To detect Xan DPCM, you will probably have to special-case your AVI demuxer to use Xan DPCM if the file uses 'Xxan' (Xan video) for its video codec. Alternately, such AVI files also contain the fourcc 'Axan' in the 'auds' chunk of the AVI header.

Definition in file dpcm.c.

Macro Definition Documentation

DPCM_DECODER

#define DPCM_DECODER	(		id_,
			name_,
			long_name_
	)

Value:

AVCodec ff_ ## name_ ## _decoder = {                        \
    .name           = #name_,                               \
    .long_name      = NULL_IF_CONFIG_SMALL(long_name_),     \
    .type           = AVMEDIA_TYPE_AUDIO,                   \
    .id             = id_,                                  \
    .priv_data_size = sizeof(DPCMContext),                  \
    .init           = dpcm_decode_init,                     \
    .decode         = dpcm_decode_frame,                    \
    .capabilities   = AV_CODEC_CAP_DR1,                     \
}

Definition at line 412 of file dpcm.c.

Function Documentation

dpcm_decode_init()

static av_cold int dpcm_decode_init ( AVCodecContext *  avctx )

static

Definition at line 130 of file dpcm.c.

dpcm_decode_frame()

static int dpcm_decode_frame ( AVCodecContext *  avctx, void *  data, int *  got_frame_ptr, AVPacket *  avpkt  )

static

Definition at line 209 of file dpcm.c.

DPCM_DECODER() [1/7]

DPCM_DECODER	(	AV_CODEC_ID_DERF_DPCM	,
		derf_dpcm	,
		"DPCM Xilam DERF"
	)

DPCM_DECODER() [2/7]

DPCM_DECODER	(	AV_CODEC_ID_GREMLIN_DPCM	,
		gremlin_dpcm	,
		"DPCM Gremlin"
	)

DPCM_DECODER() [3/7]

DPCM_DECODER	(	AV_CODEC_ID_INTERPLAY_DPCM	,
		interplay_dpcm	,
		"DPCM Interplay"
	)

DPCM_DECODER() [4/7]

DPCM_DECODER	(	AV_CODEC_ID_ROQ_DPCM	,
		roq_dpcm	,
		"DPCM id RoQ"
	)

DPCM_DECODER() [5/7]

DPCM_DECODER	(	AV_CODEC_ID_SDX2_DPCM	,
		sdx2_dpcm	,
		"DPCM Squareroot-Delta-Exact"
	)

DPCM_DECODER() [6/7]

DPCM_DECODER	(	AV_CODEC_ID_SOL_DPCM	,
		sol_dpcm	,
		"DPCM Sol"
	)

DPCM_DECODER() [7/7]

DPCM_DECODER	(	AV_CODEC_ID_XAN_DPCM	,
		xan_dpcm	,
		"DPCM Xan"
	)

Variable Documentation

derf_steps

const int32_t derf_steps[96]

static

Initial value:

= {
    0, 1, 2, 3, 4, 5, 6, 7,
    8, 9, 10, 11, 12, 13, 14, 16,
    17, 19, 21, 23, 25, 28, 31, 34,
    37, 41, 45, 50, 55, 60, 66, 73,
    80, 88, 97, 107, 118, 130, 143, 157,
    173, 190, 209, 230, 253, 279, 307, 337,
    371, 408, 449, 494, 544, 598, 658, 724,
    796, 876, 963, 1060, 1166, 1282, 1411, 1552,
    1707, 1878, 2066, 2272, 2499, 2749, 3024, 3327,
    3660, 4026, 4428, 4871, 5358, 5894, 6484, 7132,
    7845, 8630, 9493, 10442, 11487, 12635, 13899, 15289,
    16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767,
}

Definition at line 52 of file dpcm.c.

Referenced by dpcm_decode_frame().

interplay_delta_table

const int16_t interplay_delta_table[]

static

Definition at line 67 of file dpcm.c.

Referenced by dpcm_decode_frame().

sol_table_old

const int8_t sol_table_old[16]

static

Initial value:

= {
      0x0,  0x1,  0x2,  0x3,  0x6,  0xA,  0xF, 0x15,
    -0x15, -0xF, -0xA, -0x6, -0x3, -0x2, -0x1,  0x0
}

Definition at line 103 of file dpcm.c.

Referenced by dpcm_decode_init().

sol_table_new

const int8_t sol_table_new[16]

static

Initial value:

= {
    0x0,  0x1,  0x2,  0x3,  0x6,  0xA,  0xF,  0x15,
    0x0, -0x1, -0x2, -0x3, -0x6, -0xA, -0xF, -0x15
}

Definition at line 108 of file dpcm.c.

Referenced by dpcm_decode_init().

sol_table_16

const int16_t sol_table_16[128]

static

Initial value:

= {
    0x000, 0x008, 0x010, 0x020, 0x030, 0x040, 0x050, 0x060, 0x070, 0x080,
    0x090, 0x0A0, 0x0B0, 0x0C0, 0x0D0, 0x0E0, 0x0F0, 0x100, 0x110, 0x120,
    0x130, 0x140, 0x150, 0x160, 0x170, 0x180, 0x190, 0x1A0, 0x1B0, 0x1C0,
    0x1D0, 0x1E0, 0x1F0, 0x200, 0x208, 0x210, 0x218, 0x220, 0x228, 0x230,
    0x238, 0x240, 0x248, 0x250, 0x258, 0x260, 0x268, 0x270, 0x278, 0x280,
    0x288, 0x290, 0x298, 0x2A0, 0x2A8, 0x2B0, 0x2B8, 0x2C0, 0x2C8, 0x2D0,
    0x2D8, 0x2E0, 0x2E8, 0x2F0, 0x2F8, 0x300, 0x308, 0x310, 0x318, 0x320,
    0x328, 0x330, 0x338, 0x340, 0x348, 0x350, 0x358, 0x360, 0x368, 0x370,
    0x378, 0x380, 0x388, 0x390, 0x398, 0x3A0, 0x3A8, 0x3B0, 0x3B8, 0x3C0,
    0x3C8, 0x3D0, 0x3D8, 0x3E0, 0x3E8, 0x3F0, 0x3F8, 0x400, 0x440, 0x480,
    0x4C0, 0x500, 0x540, 0x580, 0x5C0, 0x600, 0x640, 0x680, 0x6C0, 0x700,
    0x740, 0x780, 0x7C0, 0x800, 0x900, 0xA00, 0xB00, 0xC00, 0xD00, 0xE00,
    0xF00, 0x1000, 0x1400, 0x1800, 0x1C00, 0x2000, 0x3000, 0x4000
}

Definition at line 113 of file dpcm.c.

Referenced by dpcm_decode_frame().