1. Epic GamesDeveloper
  3. IStreamedCompressedInfo

IStreamedCompressedInfo

Default implementation of a streamed compressed audio format.

Unreal Engine C++ API Reference > Runtime > Engine

Inheritance Hierarchy

References

   
Module Engine
Header /Engine/Source/Runtime/Engine/Public/AudioDecompress.h
Include #include "AudioDecompress.h"

Syntax

class IStreamedCompressedInfo : public ICompressedAudioInfo

Remarks

Default implementation of a streamed compressed audio format. Can be subclassed to support streaming of a specific asset format. Handles all the platform independent aspects of file format streaming for you (dealing with UE streamed assets)

Variables

  Type Name Description
Protected variable uint32 AudioDataChunkIndex The chunk index where the actual audio data starts.
Protected variable uint32 AudioDataOffset Where the actual audio data starts in the current streamed chunk. Accounts for header offset.
Protected variable bool bIsStreaming Bool set before ParseHeader. Whether we are streaming a file or not.
Protected variable bool bPrintChunkFailMessage Whether or not to print the chunk fail message.
Protected variable bool bStoringEndOfFile If we're currently reading the final buffer.
Protected variable FAudioChunkHandle CurCompressedChunkHandle Chunk Handle to ensure that this chunk of streamed audio is not deleted while we are using it.
Protected variable int32 CurrentChunkIndex The current chunk index in the streamed chunks.
Protected variable TPimplPtr< FStreamedAudioChunkSeekTable > CurrentChunkSeekTable If there's a chunked seek-table present, this contains the current chunks portion.
Protected variable uint32 CurrentSampleCount How many samples we've currently read in the source file.
Protected variable TArray< uint8 > LastDecodedPCM The decoded PCM byte array from the last decoded frame.
Protected variable uint32 LastPCMByteSize The amount of PCM data in bytes was decoded last.
Protected variable uint32 LastPCMOffset The current offset in the last decoded PCM buffer.
Protected variable uint32 MaxFrameSizeSamples The maximum number of samples per decode frame.
Protected variable uint8 NumChannels Number of channels (left/right) in the source file.
Protected variable uint32 SampleStride The number of bytes per interleaved sample (NumChannels * sizeof(int16)).
Protected variable const uint8 * SrcBufferData Ptr to the current streamed chunk.
Protected variable uint32 SrcBufferDataSize Size of the current streamed chunk.
Protected variable uint32 SrcBufferOffset What byte we're currently reading in the streamed chunk.
Protected variable uint32 SrcBufferPadding Number of bytes of padding used, overridden in some implementations. Defaults to 0.
Protected variable std::atomic< int32 > StreamSeekBlockIndex When a streaming seek request comes down, this is the block we are going to.
Protected variable int32 StreamSeekBlockOffset When a streaming seek request comes down, this is the offset in to the block we want to start decoding from.
Protected variable uint32 StreamSeekToAudioFrames If using the Chunked seek-tables, we request the seek in samples so we can resolve after the chunk table loads.
Protected variable uint32 TrueSampleCount The total sample count of the source file.

Constructors

  Type Name Description
Public function    

Destructors

  Type Name Description
Public function Virtual    

Functions

  Type Name Description
Public function bool Create the compression format dependent decoder object.
Public function FDecodeResult

Decode ( const uint8* CompressedData,
const int32 CompressedDataSize,
uint8* OutPCMData,
const int32 OutputPCMDataSize
)

 Decode the input compressed frame data into output PCMData buffer.
Protected function int32

DecompressToPCMBuffer ( uint16 FrameSize
)

 Decompresses a frame of data to PCM buffer
Protected function Const const FStreamedAudioChunkSeekTable & Gets the current chunks seektable instance (or creates one)
Protected function FStreamedAudioChunkSeekTable & Gets the current chunks seektable instance (or creates one)
Public function int32 Return the size of the current compression frame
Protected function const uint8 *

GetLoadedChunk ( const FSoundWaveProxyPtr& InSoundWave,
uint32 ChunkIndex,
uint32& OutChunkSize
)

 Helper function for getting a chunk of compressed audio.
Public function Const uint32 The size of the decode PCM buffer size.
Public function Const int32  
Public function Const int32  
Protected function uint32

IncrementCurrentSampleCount ( uint32 NewSamples
)

 Adds to the count of samples that have currently been decoded
Public function bool

ParseHeader ( const uint8* InSrcBufferData,
uint32 InSrcBufferDataSize,
FSoundQualityInfo* QualityInfo
)

 Parse the header information from the input source buffer data.
Public function Virtual void Optional method to allow decoder to prepare to loop.
Protected function uint32

Read ( void* Outbuffer,
uint32 DataSize
)

 Reads from the internal source audio buffer stream of the given data size.
Protected function uint32

WriteFromDecodedPCM ( uint8* Destination,
uint32 BufferSize
)

 Writes data from decoded PCM buffer, taking into account whether some PCM has been written before
Protected function uint32

ZeroBuffer ( uint8* Destination,
uint32 BufferSize
)

 Zeroes the contents of a buffer

Overridden from ICompressedAudioInfo

  Type Name Description
Public function Virtual void

EnableHalfRate ( bool HalfRate
)

 Sets decode to half-rate
Public function Virtual void

ExpandFile ( uint8* DstBuffer,
FSoundQualityInfo* QualityInfo
)

 Decompress an entire data file to a TArray
Public function Virtual Const int32 Gets the chunk index that was last read from (for Streaming Manager requests)
Public function Virtual Const int32 Gets the offset into the chunk that was last read to (for Streaming Manager priority)
Public function Virtual Const uint32 Gets the size of the source buffer originally passed to the info class (bytes)
Public function Virtual Const int Gets the preferred size for a streaming buffer for this decompression scheme
Public function Virtual Const bool Returns whether this instance can be cast to a IStreamedCompressedInfo.
Public function Virtual bool

ReadCompressedData ( uint8* Destination,
bool bLooping,
uint32 BufferSize
)

 Decompresses data to raw PCM data.
Public function Virtual bool

ReadCompressedInfo ( const uint8* InSrcBufferData,
uint32 InSrcBufferDataSize,
FSoundQualityInfo* QualityInfo
)

 Reads the header information of a compressed format
Public function Virtual void

SeekToTime ( const float SeekTime
)

 Seeks to time (Some formats might not be seekable)
Public function Virtual bool

StreamCompressedData ( uint8* Destination,
bool bLooping,
uint32 BufferSize,
int32& OutNumBytesStreamed
)

 Decompresses streamed data to raw PCM data.
Public function Virtual bool

StreamCompressedInfoInternal ( const FSoundWaveProxyPtr& InWaveProxy,
FSoundQualityInfo* QualityInfo
)

 Internal override implemented by subclasses.
Public function Virtual Const bool Following functions are optional if streaming is supported //.
Public function Virtual Const bool Whether the decompressed audio will be arranged using Vorbis' channel ordering See http://www.xiph.org/vorbis/doc/Vorbis_I_spec.html#x1-800004.3.9 for details

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