ModifyingTags

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• Modifying Tags
  • mp4tag_set_tag
  • mp4tag_set_binary_tag
  • mp4tag_delete_tag
  • mp4tag_clean_tags

Modifying Tags

These routines modify the list of tags internally. The MP4 file is not modified until the mp4tag_write_tags function is called.

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mp4tag_set_tag

Sets the specified tag to a new value.

mp4tag_set_tag is used for both string values and binary data values (e.g. 'covr').

When setting binary data, the data argument specifies a file to read to load the binary data. If the application already has the binary data in memory, the mp4tag_set_binary_tag function should be used.

int mp4tag_set_tag (libmp4tag_t *libmp4tag, const char *tag, const char *data, bool forcebinary)

libmp4tag : The libmp4tag_t structure returned from mp4tag_open.

tag : The tag name.

data : The value to set.

forcebinary : If setting a tag with a binary value, and the tag is not currently set, forcebinary should be set to true. Used for custom tags.

Returns: MP4TAG_OK or other error code.

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mp4tag_set_binary_tag

Available with version 1.2.0.

Used when the binary data is already in the application's memory.

int mp4tag_set_binary_tag (libmp4tag_t *libmp4tag, const char *tag, const char *data, size_t datalen)

libmp4tag : The libmp4tag_t structure returned from mp4tag_open.

tag : The tag name.

data : The value to set.

datalen : The length of the data.

Returns: MP4TAG_OK or other error code.

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mp4tag_delete_tag

Delete the specified tag.

int mp4tag_delete_tag (libmp4tag_t *libmp4tag, const char *tag)

libmp4tag : The libmp4tag_t structure returned from mp4tag_open.

tag : The name of the tag to delete.

Returns: MP4TAG_OK or other error code.

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mp4tag_clean_tags

Deletes all tags.

int mp4tag_clean_tags (libmp4tag_t *libmp4tag);

libmp4tag : The libmp4tag_t structure returned from mp4tag_open.

Returns: MP4TAG_OK or other error code.