SFBAudioConverter


@interface SFBAudioConverter : NSObject

An audio converter converts audio from one format to another through a PCM intermediate format.

An audio converter reads PCM audio from an audio decoder in the decoder’s processing format, converts that audio to an intermediate PCM format, and then writes the intermediate PCM audio to an audio encoder which performs the final conversion to the desired format.

The decoder’s processing format and intermediate format must both be PCM but do not have to have the same sample rate, bit depth, channel count, or channel layout.

AVAudioConverter is used to convert from the decoder’s processing format to the intermediate format, performing sample rate conversion and channel mapping as required.


                    
                    
                    +convertFromURL:toURL:error:

Converts audio and writes to the specified URL

Note

The file type to create is inferred from the file extension of \c destinationURL

Declaration

Objective-C

+ (BOOL)convertFromURL:(nonnull NSURL *)sourceURL
                 toURL:(nonnull NSURL *)destinationURL
                 error:(NSError *_Nullable *_Nullable)error;

Parameters

`sourceURL`	The URL to convert
`destinationURL`	The destination URL
`error`	An optional pointer to an \c NSError object to receive error information

Return Value

\c YES on success, \c NO otherwise


                    
                    
                    +convertFromURL:usingEncoder:error:

Converts audio using \c encoder

Declaration

Objective-C

+ (BOOL)convertFromURL:(nonnull NSURL *)sourceURL
          usingEncoder:(nonnull id<SFBPCMEncoding>)encoder
                 error:(NSError *_Nullable *_Nullable)error;

Parameters

`sourceURL`	The URL to convert
`encoder`	The encoder processing the decoded audio
`error`	An optional pointer to an \c NSError object to receive error information

Return Value

\c YES on success, \c NO otherwise


                    
                    
                    +convertFromDecoder:toURL:error:

Converts audio from \c decoder and writes to the specified URL

Note

The file type to create is inferred from the file extension of \c destinationURL

Declaration

Objective-C

+ (BOOL)convertFromDecoder:(nonnull id<SFBPCMDecoding>)decoder
                     toURL:(nonnull NSURL *)destinationURL
                     error:(NSError *_Nullable *_Nullable)error;

Parameters

`decoder`	The decoder providing the audio to convert
`destinationURL`	The destination URL
`error`	An optional pointer to an \c NSError object to receive error information

Return Value

\c YES on success, \c NO otherwise


                    
                    
                    +convertFromDecoder:usingEncoder:error:

Converts audio from \c decoder using \c encoder

Declaration

Objective-C

+ (BOOL)convertFromDecoder:(nonnull id<SFBPCMDecoding>)decoder
              usingEncoder:(nonnull id<SFBPCMEncoding>)encoder
                     error:(NSError *_Nullable *_Nullable)error;

Parameters

`decoder`	The decoder providing the audio to convert
`encoder`	The encoder processing the decoded audio
`error`	An optional pointer to an \c NSError object to receive error information

Return Value

\c YES on success, \c NO otherwise

+new
Unavailable

Undocumented
Declaration
Objective-C

+ (instancetype)new NS_UNAVAILABLE;
-init
Unavailable

Undocumented
Declaration
Objective-C

- (instancetype)init NS_UNAVAILABLE;


                    
                    
                    -initWithURL:destinationURL:

Returns an initialized \c SFBAudioConverter object for the given URLs or \c nil on failure

Declaration

Objective-C

- (nullable instancetype)initWithURL:(nonnull NSURL *)sourceURL
                      destinationURL:(nonnull NSURL *)destinationURL;

Parameters

`sourceURL`	The source URL
`destinationURL`	The destination URL

Return Value

An initialized \c SFBAudioConverter object for the specified URLs, or \c nil on failure


                    
                    
                    -initWithURL:destinationURL:error:

Returns an initialized \c SFBAudioConverter object for the given URLs or \c nil on failure

Declaration

Objective-C

- (nullable instancetype)initWithURL:(nonnull NSURL *)sourceURL
                      destinationURL:(nonnull NSURL *)destinationURL
                               error:(NSError *_Nullable *_Nullable)error;

Parameters

`sourceURL`	The source URL
`destinationURL`	The destination URL
`error`	An optional pointer to a \c NSError to receive error information

Return Value

An initialized \c SFBAudioConverter object for the specified URLs, or \c nil on failure


                    
                    
                    -initWithURL:encoder:

Returns an initialized \c SFBAudioConverter object for the given URL and encoder or \c nil on failure

Declaration

Objective-C

- (nullable instancetype)initWithURL:(nonnull NSURL *)sourceURL
                             encoder:(nonnull id<SFBPCMEncoding>)encoder;

Parameters

`sourceURL`	The source URL
`encoder`	The encoder

Return Value

An initialized \c SFBAudioConverter object for the specified URL and encoder, or \c nil on failure


                    
                    
                    -initWithURL:encoder:error:

Returns an initialized \c SFBAudioConverter object for the given URL and encoder or \c nil on failure

Declaration

Objective-C

- (nullable instancetype)initWithURL:(nonnull NSURL *)sourceURL
                             encoder:(nonnull id<SFBPCMEncoding>)encoder
                               error:(NSError *_Nullable *_Nullable)error;

Parameters

`sourceURL`	The source URL
`encoder`	The encoder
`error`	An optional pointer to a \c NSError to receive error information

Return Value

An initialized \c SFBAudioConverter object for the specified URL and encoder, or \c nil on failure


                    
                    
                    -initWithDecoder:destinationURL:

Returns an initialized \c SFBAudioConverter object for the given decoder and URL or \c nil on failure

Declaration

Objective-C

- (nullable instancetype)initWithDecoder:(nonnull id<SFBPCMDecoding>)decoder
                          destinationURL:(nonnull NSURL *)destinationURL;

Parameters

`decoder`	The decoder
`destinationURL`	The destination URL

Return Value

An initialized \c SFBAudioConverter object for the specified decoder and URL, or \c nil on failure


                    
                    
                    -initWithDecoder:destinationURL:error:

Returns an initialized \c SFBAudioConverter object for the given decoder and URL or \c nil on failure

Declaration

Objective-C

- (nullable instancetype)initWithDecoder:(nonnull id<SFBPCMDecoding>)decoder
                          destinationURL:(nonnull NSURL *)destinationURL
                                   error:(NSError *_Nullable *_Nullable)error;

Parameters

`decoder`	The decoder
`destinationURL`	The destination URL
`error`	An optional pointer to a \c NSError to receive error information

Return Value

An initialized \c SFBAudioConverter object for the specified decoder and URL, or \c nil on failure


                    
                    
                    -initWithDecoder:encoder:

Returns an initialized \c SFBAudioConverter object for the given decoder and encoder or \c nil on failure

Declaration

Objective-C

- (nullable instancetype)initWithDecoder:(nonnull id<SFBPCMDecoding>)decoder
                                 encoder:(nonnull id<SFBPCMEncoding>)encoder;

Parameters

`decoder`	The decoder
`encoder`	The encoder

Return Value

An initialized \c SFBAudioConverter object for the specified decoder and encoder, or \c nil on failure


                    
                    
                    -initWithDecoder:encoder:error:

Returns an initialized \c SFBAudioConverter object for the given decoder and encoder or \c nil on failure

Declaration

Objective-C

- (nullable instancetype)initWithDecoder:(nonnull id<SFBPCMDecoding>)decoder
                                 encoder:(nonnull id<SFBPCMEncoding>)encoder
                                   error:(NSError *_Nullable *_Nullable)error;

Parameters

`decoder`	The decoder
`encoder`	The encoder
`error`	An optional pointer to a \c NSError to receive error information

Return Value

An initialized \c SFBAudioConverter object for the specified decoder and encoder, or \c nil on failure


                    
                    
                    -initWithDecoder:encoder:requestedIntermediateFormat:error:

Returns an initialized \c SFBAudioConverter object for the given decoder and encoder or \c nil on failure

Declaration

Objective-C

- (nullable instancetype)initWithDecoder:(nonnull id<SFBPCMDecoding>)decoder
                                 encoder:(nonnull id<SFBPCMEncoding>)encoder
             requestedIntermediateFormat:
                 (nullable AVAudioFormat *_Nonnull (^)(AVAudioFormat *_Nonnull))
                     intermediateFormatBlock
                                   error:(NSError *_Nullable *_Nullable)error;

Parameters

`decoder`	The decoder
`encoder`	The encoder
`intermediateFormatBlock`	An optional block to receive the proposed intermediate format and return the requested intermediate format. A change in intermediate format allows operations such as sample rate conversion or channel mapping.
`error`	An optional pointer to a \c NSError to receive error information

Return Value

An initialized \c SFBAudioConverter object for the specified decoder and encoder, or \c nil on failure

Conversion Information

decoder
The decoder supplying the audio to be converted
Declaration
Objective-C

@property (nonatomic, readonly) id<SFBPCMDecoding> _Nonnull decoder;
intermediateConverter
The AVAudioConverter object producing the intermediate PCM audio

Properties such as channelMap, dither, downmix, sampleRateConverterQuality, and sampleRateConverterAlgorithm may be set before conversion.
Declaration
Objective-C

@property (nonatomic, readonly) AVAudioConverter *_Nonnull intermediateConverter;
encoder
The encoder receving the intermediate audio for encoding
Declaration
Objective-C

@property (nonatomic, readonly) id<SFBPCMEncoding> _Nonnull encoder;

Conversion


                    
                    
                    -convertReturningError:

Converts audio

Declaration

Objective-C

- (BOOL)convertReturningError:(NSError *_Nullable *_Nullable)error;

Parameters


                                error

An optional pointer to an \c NSError object to receive error information

Return Value

\c YES on success, \c NO otherwise