SYNOPSIS

#include <sys/types.h>
#include <ltcsmpte/framerate.h>

Data Structures

struct SMPTEFrame
Raw 80 bit SMPTE frame.
struct SMPTETime
Human readable time representation.
struct SMPTEFrameExt
Extended SMPTE frame The maximum error for startpos is 1/80 of a frame.

Defines

#define FPRNT_TIME '%lf'

#define TIME_DELIM '\t'

#define WRITE_DECODER_BIPHASE_DIAGNOSTICS(A, B, C, D, E)

#define WRITE_DECODER_BITS_DIAGNOSTICS(A, B, C, D, E)

#define USE8BIT

#define SAMPLE_AND_CURVE_ARE_DIFFERENT_TYPE

#define SAMPLE_CENTER 128

#define CURVE_MIN -127

#define CURVE_MAX 127

#define SAMPLE_IS_UNSIGNED

#define SAMPLE_IS_INTEGER

#define LTC_FRAME_BIT_COUNT 80

Typedefs

typedef double timeu

typedef unsigned char sample_t

typedef short curve_sample_t

typedef int diagnostics_t

typedef struct SMPTEFrame SMPTEFrame
Raw 80 bit SMPTE frame.
typedef struct SMPTETime SMPTETime
Human readable time representation.
typedef struct SMPTEFrameExt SMPTEFrameExt
Extended SMPTE frame The maximum error for startpos is 1/80 of a frame.
typedef struct SMPTEDecoder SMPTEDecoder
opaque structure.
typedef struct SMPTEEncoder SMPTEEncoder
opaque structure see: SMPTEEncoderCreate, SMPTEFreeEncoder

Functions

int SMPTEFrameToTime (SMPTEFrame *frame, SMPTETime *stime)
convert binary SMPTEFrame into SMPTETime struct
int SMPTETimeToFrame (SMPTETime *stime, SMPTEFrame *frame)
convert SMPTETime struct into it's binary SMPTE representation.
int SMPTEFrameReset (SMPTEFrame *frame)
set all values of a SMPTE FRAME to zero except for the sync-word (0x3FFD) at the end.
int SMPTEFrameIncrease (SMPTEFrame *frame, int framesPerSec)
increments the SMPTE by one SMPTE-Frame (1/framerate seconds)
SMPTEDecoder * SMPTEDecoderCreate (int sampleRate, FrameRate *fps, int queueSize, int correctJitter)
Create a new decoder.
int SMPTEFreeDecoder (SMPTEDecoder *d)
release memory of Decoder structure.
int SMPTEDecoderErrorReset (SMPTEDecoder *decoder)
Reset the decoder error tracking internals.
int SMPTEDecoderWrite (SMPTEDecoder *decoder, sample_t *buf, int size, long int posinfo)
Feed the SMPTE decoder with new samples.
int SMPTEDecoderRead (SMPTEDecoder *decoder, SMPTEFrameExt *frame)
All decoded SMPTE frames are placed in a queue.
int SMPTEDecoderReadLast (SMPTEDecoder *decoder, SMPTEFrameExt *frame)
flush unread LTCs in queue and return the last timestamp.
int SMPTEDecoderFrameToMillisecs (SMPTEDecoder *decoder, SMPTEFrameExt *frame, int *timems)
Convert the frame to time in milliseconds.
timeu SMPTEDecoderSamplesToSeconds (SMPTEDecoder *d, long int sampleCount)
Convert the index or position of a sample to its position in time (seconds) relative to the first sample.
int SMPTEDecoderErrors (SMPTEDecoder *decoder, int *errors)
get accumulated error count since last reset.
SMPTEEncoder * SMPTEEncoderCreate (int sampleRate, FrameRate *fps)
Allocate and initialize LTC encoder sampleRate: audio sample rate (eg.
int SMPTEFreeEncoder (SMPTEEncoder *e)
release encoder data structure
int SMPTESetNsamples (SMPTEEncoder *e, int val)
set internal Audio-sample counter.
int SMPTEGetNsamples (SMPTEEncoder *e)
returns the current values of the Audio-sample counter.
int SMPTEEncIncrease (SMPTEEncoder *e)
moves the SMPTE to the next frame.
int SMPTESetTime (SMPTEEncoder *e, SMPTETime *t)
sets the current encoder SMPTE frame to SMPTETime.
int SMPTEGetTime (SMPTEEncoder *e, SMPTETime *t)
set t from current Encoder timecode
long int SMPTEGetVideoFrameNumber (SMPTEEncoder *e)
returns the current value of the encoder's SMPTE frame converted to video-frames
int SMPTEGetTimeInMillisecs (SMPTEEncoder *e)
returns the current value of the encoder's SMPTE frame converted to ms
int SMPTEGetBuffer (SMPTEEncoder *e, sample_t *buf)
returns and flushes the accumulated Encoded Audio.
size_t SMPTEGetBuffersize (SMPTEEncoder *e)
returns the size of the accumulated encoded Audio in bytes.
int SMPTEEncode (SMPTEEncoder *e, int byteCnt)
Generate LTC audio for byte 'byteCnt' of the current frame into the buffer of Encoder e.

Detailed Description

libltcsmpte - en+decode linear SMPTE timecode

Author:

Robin Gareus <[email protected]>

Copyright (C) 2006 Robin Gareus <[email protected]> Copyright (C) 2008-2009 Jan <[email protected]>

inspired by SMPTE Decoder - Maarten de Boer <[email protected]>

This program is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

Definition in file ltcsmpte.h.

Define Documentation

#define CURVE_MAX 127

Definition at line 90 of file ltcsmpte.h.

#define CURVE_MIN -127

Definition at line 89 of file ltcsmpte.h.

#define FPRNT_TIME '%lf'

Examples: tests/decoder.c.

Definition at line 51 of file ltcsmpte.h.

#define LTC_FRAME_BIT_COUNT 80

Definition at line 98 of file ltcsmpte.h.

#define SAMPLE_AND_CURVE_ARE_DIFFERENT_TYPE

Definition at line 87 of file ltcsmpte.h.

#define SAMPLE_CENTER 128

Definition at line 88 of file ltcsmpte.h.

#define SAMPLE_IS_INTEGER

Definition at line 92 of file ltcsmpte.h.

#define SAMPLE_IS_UNSIGNED

Definition at line 91 of file ltcsmpte.h.

#define TIME_DELIM '\t'

Examples: tests/decoder.c.

Definition at line 52 of file ltcsmpte.h.

#define USE8BIT

Definition at line 84 of file ltcsmpte.h.

#define WRITE_DECODER_BIPHASE_DIAGNOSTICS(A, B, C, D, E)

Definition at line 58 of file ltcsmpte.h.

#define WRITE_DECODER_BITS_DIAGNOSTICS(A, B, C, D, E)

Definition at line 59 of file ltcsmpte.h.

Typedef Documentation

typedef short curve_sample_t

Definition at line 86 of file ltcsmpte.h.

typedef int diagnostics_t

Definition at line 93 of file ltcsmpte.h.

typedef unsigned char sample_t

Definition at line 85 of file ltcsmpte.h.

typedef struct SMPTEDecoder SMPTEDecoder

opaque structure. see: SMPTEDecoderCreate, SMPTEFreeDecoder

Definition at line 211 of file ltcsmpte.h.

typedef struct SMPTEEncoder SMPTEEncoder

opaque structure see: SMPTEEncoderCreate, SMPTEFreeEncoder

Definition at line 217 of file ltcsmpte.h.

typedef struct SMPTEFrame SMPTEFrame

Raw 80 bit SMPTE frame.

typedef struct SMPTEFrameExt SMPTEFrameExt

Extended SMPTE frame The maximum error for startpos is 1/80 of a frame. Usually it is 0;

typedef struct SMPTETime SMPTETime

Human readable time representation.

typedef double timeu

Definition at line 50 of file ltcsmpte.h.

Function Documentation

SMPTEDecoder* SMPTEDecoderCreate (int sampleRate, FrameRate * fps, int queueSize, int correctJitter)

Create a new decoder. Pass sample rate, number of smpte frames per seconds, and the size of the internal queue where decoded frames are stored. Set correctJitter flag, to correct jitter resulting from audio fragment size when decoding from a realtime audiostream. This works only correctly when buffers of exactly fragment size are passed to SMPTEDecoderWrite. (as discussed on LAD [msgID])

Examples: tests/decoder.c.

int SMPTEDecoderErrorReset (SMPTEDecoder * decoder)

Reset the decoder error tracking internals.

int SMPTEDecoderErrors (SMPTEDecoder * decoder, int * errors)

get accumulated error count since last reset.

Examples: tests/decoder.c.

int SMPTEDecoderFrameToMillisecs (SMPTEDecoder * decoder, SMPTEFrameExt * frame, int * timems)

Convert the frame to time in milliseconds. This uses the position of the end of the frame related to the sample-time to compensate for jitter.

Examples: tests/decoder.c.

int SMPTEDecoderRead (SMPTEDecoder * decoder, SMPTEFrameExt * frame)

All decoded SMPTE frames are placed in a queue. This function gets a frame from the queue, and stores it in SMPTEFrameExt* frame. Returns 1 on success, 0 when no frames where on the queue, and and errorcode otherwise.

Examples: tests/decoder.c.

int SMPTEDecoderReadLast (SMPTEDecoder * decoder, SMPTEFrameExt * frame)

flush unread LTCs in queue and return the last timestamp. (note that the last timestamp may not be the latest if the queue has overflown!)

timeu SMPTEDecoderSamplesToSeconds (SMPTEDecoder * d, long int sampleCount)

Convert the index or position of a sample to its position in time (seconds) relative to the first sample.

Examples: tests/decoder.c.

int SMPTEDecoderWrite (SMPTEDecoder * decoder, sample_t * buf, int size, long int posinfo)

Feed the SMPTE decoder with new samples. parse raw audio for LTC timestamps. If found, store them in the Decoder queue (see SMPTEDecoderRead) always returns 1 ;-) d: the decoder buf: pointer to sample_t (defaults to unsigned 8 bit) mono audio data size: number of bytes to parse posinfo: (optional) byte offset in stream to set LTC location offset

Examples: tests/decoder.c.

int SMPTEEncIncrease (SMPTEEncoder * e)

moves the SMPTE to the next frame. it uses SMPTEFrameIncrease().

Examples: tests/encoder.c.

int SMPTEEncode (SMPTEEncoder * e, int byteCnt)

Generate LTC audio for byte 'byteCnt' of the current frame into the buffer of Encoder e. LTC has 10 bytes per frame: 0 <= bytecnt < 10 use SMPTESetTime(..) to set the current frame before Encoding. see tests/encoder.c for an example.

Examples: tests/encoder.c.

SMPTEEncoder* SMPTEEncoderCreate (int sampleRate, FrameRate * fps)

Allocate and initialize LTC encoder sampleRate: audio sample rate (eg. 48000) fps: framerate

Examples: tests/encoder.c.

int SMPTEFrameIncrease (SMPTEFrame * frame, int framesPerSec)

increments the SMPTE by one SMPTE-Frame (1/framerate seconds)

int SMPTEFrameReset (SMPTEFrame * frame)

set all values of a SMPTE FRAME to zero except for the sync-word (0x3FFD) at the end. This will also clear the dfbit.

int SMPTEFrameToTime (SMPTEFrame * frame, SMPTETime * stime)

convert binary SMPTEFrame into SMPTETime struct

Examples: tests/decoder.c.

int SMPTEFreeDecoder (SMPTEDecoder * d)

release memory of Decoder structure.

Examples: tests/decoder.c.

int SMPTEFreeEncoder (SMPTEEncoder * e)

release encoder data structure

Examples: tests/encoder.c.

int SMPTEGetBuffer (SMPTEEncoder * e, sample_t * buf)

returns and flushes the accumulated Encoded Audio. returns the number of bytes written to the memory area pointed to by buf.

no overflow check is perfomed! use DTMFGetBuffersize().

Examples: tests/encoder.c.

size_t SMPTEGetBuffersize (SMPTEEncoder * e)

returns the size of the accumulated encoded Audio in bytes.

Examples: tests/encoder.c.

int SMPTEGetNsamples (SMPTEEncoder * e)

returns the current values of the Audio-sample counter. ie. the number of encoded samples.

Examples: tests/encoder.c.

int SMPTEGetTime (SMPTEEncoder * e, SMPTETime * t)

set t from current Encoder timecode

int SMPTEGetTimeInMillisecs (SMPTEEncoder * e)

returns the current value of the encoder's SMPTE frame converted to ms

Examples: tests/encoder.c.

long int SMPTEGetVideoFrameNumber (SMPTEEncoder * e)

returns the current value of the encoder's SMPTE frame converted to video-frames

int SMPTESetNsamples (SMPTEEncoder * e, int val)

set internal Audio-sample counter. SMPTEEncode() increments this counter when it encodes samples.

Examples: tests/encoder.c.

int SMPTESetTime (SMPTEEncoder * e, SMPTETime * t)

sets the current encoder SMPTE frame to SMPTETime.

Examples: tests/encoder.c.

int SMPTETimeToFrame (SMPTETime * stime, SMPTEFrame * frame)

convert SMPTETime struct into it's binary SMPTE representation.

Author

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