---
name: "ost_AudioCodec"
section: "3"
platform: "linux"
package: "libccaudio2-doc"
version: "1.0.0-2"
release: "Debian 6.0 (Squeeze)"
platforms: ["linux"]
url: "https://new.carta.tech/ost_AudioCodec"
---

# ost\_AudioCodec(3)

The codec class is a virtual used for transcoding audio samples between linear frames (or other known format) and an encoded 'sample' buffer.

## NAME

ost::AudioCodec - The codec class is a virtual used for transcoding audio samples between linear frames (or other known format) and an encoded 'sample' buffer.

## SYNOPSIS

`#include <audio2.h>`

Inherits **ost::Audio**.

### Public Member Functions

**AudioCodec** (const char \***name**, **Encoding** **encoding**)\
 *Base for codecs, create a named coded of a specific encoding.*  virtual **~AudioCodec** ()\
 virtual **Level** **getImpulse** (void \*buffer, unsigned number=0)\
 *Get the impulse energy level of a frame of X samples in the specified codec format.*  virtual **Level** **getPeak** (void \*buffer, unsigned number=0)\
 *Get the peak energy level within the frame of X samples.*  virtual bool **isSilent** (**Level** threashold, void \*buffer, unsigned number=0)\
 *Signal if the current audio frame is silent.*  virtual unsigned **encode** (**Linear** buffer, void \*dest, unsigned number=0)=0\
 *Encode a linear sample frame into the codec sample buffer.*  virtual unsigned **encodeBuffered** (**Linear** Buffer, **Encoded** dest, unsigned number)\
 *Encode linear samples buffered into the coded.*  virtual unsigned **decode** (**Linear** buffer, void \*source, unsigned number=0)=0\
 *Decode the sample frame into linear samples.*  virtual unsigned **decodeBuffered** (**Linear** buffer, **Encoded** source, unsigned len)\
 *Buffer and decode data into linear samples.*  virtual unsigned **getEstimated** (void)\
 *Get estimated data required for buffered operations.*  virtual unsigned **getRequired** (void)\
 *get required samples for encoding.*  virtual unsigned **getPacket** (**Encoded** destination, **Encoded** data, unsigned size)\
 *Get a packet of data rather than decode.*  **Info** **getInfo** (void)\
 *Get an info description for this codec.*

### Static Public Member Functions

static void **endCodec** (**AudioCodec** \*codec)\
 *End use of a requested codec.*  static **AudioCodec** \* **getCodec** (**Encoding** **encoding**, const char \*format=NULL, bool loaded=false)\
 *Get the codec base class for accessing a specific derived codec identified by encoding type and optional spd info.*  static **AudioCodec** \* **getCodec** (**Info** &**info**, bool loaded=false)\
 *Get the codec base class for accessing a specific derived codec identified by audio source descriptor.*  static bool **load** (const char \***name**)\
 *Load a named codec set into process memory.*  static bool **load** (**Encoding** **encoding**)\
 *Find and load a codec file by it's encoding type.*

### Protected Member Functions

**AudioCodec** ()\
 virtual **AudioCodec** \* **getByFormat** (const char \*format)\
 *often used to create a 'new' codec of a subtype based on encoding format, default returns the current codec entity.*  virtual **AudioCodec** \* **getByInfo** (**Info** &**info**)\
 *get a codec by audio source info descriptor.*

### Protected Attributes

**AudioCodec** \* **next**\
 **Encoding** **encoding**\
 const char \* **name**\
 **Info** **info**\

### Static Protected Attributes

static **AudioCodec** \* **first**\

## Detailed Description

The codec class is a virtual used for transcoding audio samples between linear frames (or other known format) and an encoded 'sample' buffer.

This class is only abstract and describes the core interface for loadable codec modules. This class is normally merged with AudioSample. A derived AudioCodecXXX will typically include a AudioRegisterXXX static class to automatically initialize and register the codec with the codec registry.

**Author:**

David Sugar \<dyfet@ostel.com\> process codec interface.

## Constructor & Destructor Documentation

### ost::AudioCodec::AudioCodec ()` [protected]`

### ost::AudioCodec::AudioCodec (const char \* name, Encoding encoding)

Base for codecs, create a named coded of a specific encoding.

**Parameters:**

*name* of codec. \
 *encoding* type of codec.

### virtual ost::AudioCodec::~AudioCodec ()` [inline, virtual]`

## Member Function Documentation

### virtual AudioCodec\* ost::AudioCodec::getByFormat (const char \* format)` [inline, protected, virtual]`

often used to create a 'new' codec of a subtype based on encoding format, default returns the current codec entity.

**Returns:**

pointer to an active codec or NULL if not found.

**Parameters:**

*format* name from spd.

### virtual AudioCodec\* ost::AudioCodec::getByInfo (Info & info)` [inline, protected, virtual]`

get a codec by audio source info descriptor.

**Returns:**

pointer to an active codec or NULL if not found.

**Parameters:**

*info* audio source descriptor.

### static void ost::AudioCodec::endCodec (AudioCodec \* codec)` [static]`

End use of a requested codec.

If constructed then will be deleted.

**Parameters:**

*codec* pointer to getCodec returned coded pointer.

### static AudioCodec\* ost::AudioCodec::getCodec (Encoding encoding, const char \* format = `NULL`, bool loaded = `false`)` [static]`

Get the codec base class for accessing a specific derived codec identified by encoding type and optional spd info.

**Returns:**

pointer to codec for processing.

**Parameters:**

*encoding* format requested. \
 *format* spd options to pass to codec being created. \
 *loaded* true to load if not already in memory.

### static AudioCodec\* ost::AudioCodec::getCodec (Info & info, bool loaded = `false`)` [static]`

Get the codec base class for accessing a specific derived codec identified by audio source descriptor.

**Returns:**

pointer to codec for processing.

**Parameters:**

*info* source descriptor for codec being requested. \
 *loaded* true to load codec if not already in memory.

### static bool ost::AudioCodec::load (const char \* name)` [static]`

Load a named codec set into process memory.

**Returns:**

true if successful.

**Parameters:**

*name* of codec set to load.

### static bool ost::AudioCodec::load (Encoding encoding)` [static]`

Find and load a codec file by it's encoding type.

Converts the type into a codec name and invokes the other loader...

**Returns:**

true if successful.

**Parameters:**

*encoding* type for file.

### virtual Level ost::AudioCodec::getImpulse (void \* buffer, unsigned number = `0`)` [virtual]`

Get the impulse energy level of a frame of X samples in the specified codec format.

**Returns:**

average impulse energy of frame (sumnation).

**Parameters:**

*buffer* of encoded samples. \
 *number* of encoded samples.

### virtual Level ost::AudioCodec::getPeak (void \* buffer, unsigned number = `0`)` [virtual]`

Get the peak energy level within the frame of X samples.

**Returns:**

peak energy impulse in frame (largest).

**Parameters:**

*buffer* of encoded samples. \
 *number* of encoded samples.

### virtual bool ost::AudioCodec::isSilent (Level threashold, void \* buffer, unsigned number = `0`)` [virtual]`

Signal if the current audio frame is silent.

This can be deterimed either by an impulse computation, or, in some cases, some codecs may signal and flag silent packets.

**Returns:**

true if silent

**Parameters:**

*threashold* to use if not signaled. \
 *buffer* of encoded samples. \
 *number* of encoded samples.

### virtual unsigned ost::AudioCodec::encode (Linear buffer, void \* dest, unsigned number = `0`)` [pure virtual]`

Encode a linear sample frame into the codec sample buffer.

**Returns:**

number of bytes written.

**Parameters:**

*buffer* linear sample buffer to use. \
 *dest* buffer to store encoded results. \
 *number* of samples.

### virtual unsigned ost::AudioCodec::encodeBuffered (Linear Buffer, Encoded dest, unsigned number)` [virtual]`

Encode linear samples buffered into the coded.

**Returns:**

number of bytes written or 0 if incomplete.

**Parameters:**

*buffer* linear samples to post. \
 *destination* of encoded audio. \
 *number* of samples being buffered.

### virtual unsigned ost::AudioCodec::decode (Linear buffer, void \* source, unsigned number = `0`)` [pure virtual]`

Decode the sample frame into linear samples.

**Returns:**

number of bytes scanned or returned

**Parameters:**

*buffer* sample buffer to save linear samples into. \
 *source* for encoded data. \
 *number* of samples to extract.

### virtual unsigned ost::AudioCodec::decodeBuffered (Linear buffer, Encoded source, unsigned len)` [virtual]`

Buffer and decode data into linear samples.

This is needed for audio formats that have irregular packet sizes.

**Returns:**

number of samples actually decoded.

**Parameters:**

*destination* for decoded data. \
 *source* for encoded data. \
 *number* of bytes being sent.

### virtual unsigned ost::AudioCodec::getEstimated (void)` [virtual]`

Get estimated data required for buffered operations.

**Returns:**

estimated number of bytes required for decode.

### virtual unsigned ost::AudioCodec::getRequired (void)` [virtual]`

get required samples for encoding.

**Returns:**

required number of samples for encoder buffer.

### virtual unsigned ost::AudioCodec::getPacket (Encoded destination, Encoded data, unsigned size)` [virtual]`

Get a packet of data rather than decode.

This is tied with getEstimated.

**Returns:**

size of data packet or 0 if not complete.

**Parameters:**

*destination* to save. \
 *data* to push into buffer. \
 *number* of bytes to push.

### Info ost::AudioCodec::getInfo (void)` [inline]`

Get an info description for this codec.

**Returns:**

info.

## Member Data Documentation

### AudioCodec\* ost::AudioCodec::first` [static, protected]`

### AudioCodec\* ost::AudioCodec::next` [protected]`

### Encoding ost::AudioCodec::encoding` [protected]`

### const char\* ost::AudioCodec::name` [protected]`

### Info ost::AudioCodec::info` [protected]`

## Author

Generated automatically by Doxygen for ccAudio from the source code.