BASS_WEBM_StreamCreateFile

Creates a sample stream from a WebM or Matroska file.

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

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.
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_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.

track

The audio track to play from the file... 1 = first, 0 = first playable track. When requesting the first playable track, all tracks will be checked in numerical order until a playable one is found. Non-audio tracks are ignored (not counted).

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_TRACK	track is invalid.
BASS_ERROR_NOTAUDIO	The file does not contain audio, or it also contains video and videos are disabled.
BASS_ERROR_CODEC	The file uses a codec that is not available/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

WebM is a subset of the Matroska file format. WebM files can contain Vorbis or Opus audio data, while Matroska also supports other codecs including AAC / AC3 / MP3 / PCM. BASS includes support for Vorbis / MP3 / PCM, and AAC / AC3 on some platforms, but add-ons are required (loaded via BASS_PluginLoad) to support other codecs, eg. BASSOPUS for Opus. Not all Matroska features are supported but most Matroska files should be playable.

WebM and Matroska files can have tags for the file as a whole and for individual tracks. When present, they are available as a series of null-terminated UTF-8 strings from BASS_ChannelGetTags with BASS_TAG_WEBM and BASS_TAG_WEBM_TRACK, respectively. In the case of BASS_TAG_WEBM_TRACK, the active track's tags are given. When the Vorbis codec is used, BASS_TAG_OGG tags may also be available.

A single track from the file will be played by default, but if there are multiple audio tracks then BASS_ChannelSetPosition can be used with the BASS_POS_TRACK "mode" to change track (0 = first) and go to the start of it. The new track can use a different codec but it must have the same decoded sample format, otherwise the call will fail with a BASS_ERROR_FORMAT error and a new stream will need to be created for the track instead. The BASS_POS_TRACK "mode" can also be used with BASS_ChannelGetLength and BASS_ChannelGetPosition to get the number of audio tracks and the current track, respectively.

The stream's ctype value from BASS_ChannelGetInfo refers to the active track's decoder, so it does not identify a WebM or Matroska stream; the BASS_ATTRIB_WEBM attribute can be used for that.

Unless a specific track is requested in the track parameter, this function obeys the BASS_CONFIG_VIDEO option setting and will fail (BASS_ERROR_NOTAUDIO) if the file contains any video tracks when configured to do so.

BASS_WEBM_StreamCreateFile

Parameters

Return value

Error codes

Remarks

See also