BASS WMA

BASS_WMA_EncodeOpen

Initializes WMA encoding to a user defined function.

HWMENCODE BASS_WMA_EncodeOpen(
    DWORD freq,
    DWORD chans,
    DWORD flags,
    DWORD bitrate,
    WMENCODEPROC *proc,
    void *user
);

Parameters

freq

The sample rate, or a BASS channel handle if the BASS_WMA_ENCODE_SOURCE flag is specified.

chans

The number of channels. More than stereo requires WMA Pro or PCM.

flags

A combination of these flags.

BASS_SAMPLE_8BITS	8-bit sample data. If neither this or the BASS_SAMPLE_FLOAT flags are specified, then 16-bit data is expected.
BASS_SAMPLE_FLOAT	32-bit floating-point sample data.
BASS_WMA_ENCODE_SOURCE	Use the BASS channel with the handle in freq as the encoder's source. The chans parameter is ignored, as are the BASS_SAMPLE_8BITS and BASS_SAMPLE_FLOAT flags. If the BASSenc add-on is loaded, then the BASS_CONFIG_ENCODE_PRIORITY setting is used to determine where in the channel's DSP chain the encoding is performed, otherwise priority -1000 is used.
BASS_WMA_ENCODE_STANDARD	Use standard WMA encoding. If neither this or the BASS_WMA_ENCODE_PRO flag (nor the BASS_WMA_ENCODE_PCM flag) is specified, then either WMA codec could be used, depending on which supports the requested sample format and bitrate.
BASS_WMA_ENCODE_PRO	Use WMA Pro encoding.
BASS_WMA_ENCODE_PCM	Write uncompressed PCM data in an ASF container. bitrate is ignored except that it should be non-0.
BASS_WMA_ENCODE_24BIT	Encode in 24-bit, else 16-bit. 24-bit encoding requires WMA Pro or PCM.
BASS_WMA_ENCODE_SCRIPT	Enable the specification of tags mid-stream (after encoding has begun).
BASS_WMA_ENCODE_QUEUE	Queue data to feed the encoder asynchronously. This prevents BASS_WMA_EncodeWrite getting blocked by the encoder, but the application should control the rate at which data is encoded, as it is possible to queue too much data for the encoder to handle.

bitrate

The encoding bitrate, or VBR quality (100 or less).

proc

The user defined function to receive the encoded data.

user

User instance data to pass to the callback function.

Return value

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

Error codes

BASS_ERROR_WMA	The Windows Media modules (v9 or above) are not installed.
BASS_ERROR_NOTAVAIL	No codec could be found to support the requested sample format and bitrate.
BASS_ERROR_UNKNOWN	Some other mystery problem!

Remarks

Encoding to a user defined function allows any storage or delivery method to be used for the encoded WMA data. For example, encoding to memory.

The WMA codec expects 16-bit or 24-bit sample data depending on the BASS_WMA_ENCODE_24BIT flag, but BASSWMA will accept 8-bit, 16-bit or floating-point data, and convert it to the appropriate format. Use BASS_WMA_EncodeGetRates to retrieve a list of the encoding bitrates available for a specific sample format.

Use BASS_WMA_EncodeSetTag to set tags, BASS_WMA_EncodeWrite to encode sample data, and BASS_WMA_EncodeClose to finish encoding.