BASS_OPUS_StreamCreateFile

Creates a sample stream from an Opus file.

HSTREAM BASS_OPUS_StreamCreateFile(
    DWORD filetype,
    void *file,
    QWORD offset,
    QWORD length,
    DWORD flags
);

Parameters

filetype

One of the following.

BASS_FILE_NAME	file is a filename. This is the default if none is specified.
BASS_FILE_MEM	file points to a memory block, which will be read from directly, so it needs to stay valid for the lifetime of the stream.
BASS_FILE_MEMCOPY	file points to a memory block, which will be copied, so it does not need to stay valid beyond this function call. This requires BASS 2.4.18 or above.
BASS_FILE_HANDLE	file is a file handle (HANDLE) on Windows or a file descriptor (int) on other platforms, and should be seekable. It will be duplicated, so the original can be closed whenever wanted but it should not be used to access the file while the stream is. This requires BASS 2.4.18 or above.

file

The file as described by filetype.

offset

File offset to begin reading from.

length

Maximum read length... 0 = to the end of the file.

flags

A combination of these flags.

BASS_SAMPLE_FLOAT	Use 32-bit floating-point sample data. See Floating-point channels for info. If this flag is not specified, then the stream is 16-bit.
BASS_SAMPLE_3D	Enable 3D functionality. The stream must be mono. The SPEAKER flags cannot be used together with this flag.
BASS_SAMPLE_LOOP	Loop the file. This flag can be toggled at any time using BASS_ChannelFlags.
BASS_STREAM_PRESCAN	Pre-scan the file for seek points and accurate length reading in chained Opus files (has no effect on normal Opus files). This can significantly increase the time taken to create the stream, particularly with a large file and/or slow storage media.
BASS_STREAM_AUTOFREE	Automatically free the stream when playback ends.
BASS_STREAM_DECODE	Decode the sample data, without playing it. Use BASS_ChannelGetData to retrieve decoded sample data. The BASS_SAMPLE_3D, BASS_STREAM_AUTOFREE and SPEAKER flags cannot be used together with this flag.
BASS_SPEAKER_xxx	Speaker assignment flags. These flags have no effect when the stream is more than stereo.
BASS_ASYNCFILE	Read the file asynchronously. When enabled, the file is read and buffered in parallel with the decoding, to reduce the chances of the decoder being affected by I/O delays. This can be particularly useful with slow storage media and/or low latency output. The size of the file buffer is determined by the BASS_CONFIG_ASYNCFILE_BUFFER config option. This flag is ignored when streaming from memory.
BASS_UNICODE	file is in UTF-16 form. Otherwise it is ANSI on Windows and UTF-8 on other platforms. This flag is ignored when file is not a filename.

Return value

If successful, the new stream's handle is returned, else 0 is returned. Use BASS_ErrorGetCode to get the error code.

Error codes

BASS_ERROR_INIT	BASS_Init has not been successfully called.
BASS_ERROR_NOTAVAIL	The BASS_STREAM_AUTOFREE flag cannot be combined with the BASS_STREAM_DECODE flag.
BASS_ERROR_ILLPARAM	filetype and/or length is invalid. length cannot be 0 when streaming from memory.
BASS_ERROR_FILEOPEN	The file could not be opened.
BASS_ERROR_FILEFORM	The file's format is not recognised/supported.
BASS_ERROR_FORMAT	The sample format is not supported.
BASS_ERROR_SPEAKER	The specified SPEAKER flags are invalid.
BASS_ERROR_MEM	There is insufficent memory.
BASS_ERROR_NO3D	Could not initialize 3D support.
BASS_ERROR_UNKNOWN	Some other mystery problem!

Remarks

Use BASS_ChannelGetInfo to retrieve information on the format of the stream. Opus always has a sample rate of 48000 Hz, but the source material may have had a different sample rate, which is available via the BASS_ATTRIB_OPUS_ORIGFREQ attribute. The playback length of the stream can be retrieved using BASS_ChannelGetLength.

The Opus file format is Ogg-based, so the standard BASS_TAG_OGG and BASS_TAG_VENDOR tag types apply to Opus too, via BASS_ChannelGetTags.

Chained Opus files containing multiple logical bitstreams are supported, but they will need to be scanned to get their length or to seek in them. That scanning will be done at stream creation or at the first BASS_ChannelGetLength or BASS_ChannelSetPosition call, depending on whether the BASS_CONFIG_OGG_PRESCAN option is enabled (or the BASS_STREAM_PRESCAN flag is used). The BASS_POS_OGG "mode" can be used with BASS_ChannelGetLength to get the number of bitstreams and with BASS_ChannelSetPosition to seek to a particular one. A BASS_SYNC_OGG_CHANGE sync can be set via BASS_ChannelSetSync to be informed of when a new bitstream begins during decoding/playback.

To stream a file from the internet, use BASS_OPUS_StreamCreateURL. To stream from other locations, see BASS_OPUS_StreamCreateFileUser. To stream raw Opus packets (without an Ogg container), use BASS_OPUS_StreamCreate.

Example

Create a stream of an Opus file.