BASS WMA

BASS_WMA_EncodeSetTag

Sets a tag in a WMA encoding.

BOOL BASS_WMA_EncodeSetTag(
    HWMENCODE handle,
    char *tag,
    char *value,
    DWORD form
);

Parameters

handle

The encoder handle.

tag

The tag to set.The standard WMA header tags are as follows.

Title	Content title.
Author	Name of the content author.
Description	Description of the content.
Rating	Content rating.
Copyright	Content copyright message.
WM/AlbumTitle	Album title.
WM/PromotionURL	URL to an HTML page containing related information.
WM/AlbumCoverURL	URL to an HTML page containing an image of the album cover.
WM/Genre	Genre of the music.
WM/Year	Year of publication of the music.

value

The tag's text/data.

form

The format of the tag and value strings.

BASS_WMA_TAG_ANSI	ANSI strings.
BASS_WMA_TAG_UNICODE	UTF-16 strings.
BASS_WMA_TAG_UTF8	UTF-8 strings.
BASS_WMA_TAG_BINARY	value contains binary data rather than text. The length of the data is in the HIWORD.

Return value

If successful, TRUE is returned, else FALSE is returned. Use BASS_ErrorGetCode to get the error code.

Error codes

BASS_ERROR_HANDLE	handle is not valid.
BASS_ERROR_NOTAVAIL	The encoder does not have mid-stream tags enabled, so tags cannot be set once encoding has begun.
BASS_ERROR_ILLPARAM	tag and/or value is invalid.
BASS_ERROR_UNKNOWN	Some other mystery problem!

Remarks

Where the tags are located in the encoded stream depends on when this function is used. Calling this function before beginning encoding data puts the tags in the stream's header. Calling this function after encoding has begun puts the tags in the actual stream data, at the current encoding position.

Header tags must be set before encoding any data; no more header tags can be set once BASS_WMA_EncodeWrite has been called.

To set tags mid-stream (after encoding has begun), the BASS_WMA_ENCODE_SCRIPT flag needs to have been specified in the encoder's creation. A mid-stream tag typically used is "Caption", which get's displayed in Windows Media Player 9 and above (if the user has enabled captions).

When using a network encoder, it should be noted that while all header tags are sent to newly connecting clients, prior mid-stream tags are not. So if, for example, you're using the "Caption" tag to indicate the current song title, it should be sent at fairly regular intervals (not only at the start of the song).

On the playback side, mid-stream tags can be processed using BASS_ChannelSetSync (BASS_SYNC_META).

Example

Initialize encoding 44100hz 16-bit stereo sample data at 128kb/s to a file called "blah.wma", and set the title to "Blah".

HWMENCODE encoder=BASS_WMA_EncodeOpenFile(44100, 2, 0, 128000, "blah.wma");
BASS_WMA_EncodeSetTag(encoder, "Title", "Blah", BASS_WMA_TAG_ANSI); // set the title tag