Provided by: libltcsmpte-doc_0.4.4-1_all 
NAME
ltcsmpte.h -
libltcsmpte - en+decode linear SMPTE timecode
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 ' '
#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 <robin@gareus.org>
Copyright (C) 2006 Robin Gareus <robin@gareus.org> Copyright (C) 2008-2009 Jan
<jan@geheimwerk.de>
inspired by SMPTE Decoder - Maarten de Boer <mdeboer@iua.upf.es>
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 ''
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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