def update_metadata(self, metadata): """takes this track's current MetaData object as returned by get_metadata() and sets this track's metadata with any fields updated in that object raises IOError if unable to write the file """ import os from audiotools import TemporaryFile from audiotools.ogg import (PageReader, PacketReader, PageWriter, packet_to_pages) from audiotools.bitstream import BitstreamRecorder if (metadata is None): return elif (not isinstance(metadata, VorbisComment)): from .text import ERR_FOREIGN_METADATA raise ValueError(ERR_FOREIGN_METADATA) elif (not os.access(self.filename, os.W_OK)): raise IOError(self.filename) original_ogg = PacketReader(PageReader(file(self.filename, "rb"))) new_ogg = PageWriter(TemporaryFile(self.filename)) #transfer current file's identification page/packet #(the ID packet is always fixed size, and fits in one page) identification_page = original_ogg.read_page() new_ogg.write(identification_page) sequence_number = 1 #discard the current file's comment packet original_ogg.read_packet() #write the new comment packet in its own page(s) comment_writer = BitstreamRecorder(True) comment_writer.write_bytes("OpusTags") vendor_string = metadata.vendor_string.encode('utf-8') comment_writer.build("32u %db" % (len(vendor_string)), (len(vendor_string), vendor_string)) comment_writer.write(32, len(metadata.comment_strings)) for comment_string in metadata.comment_strings: comment_string = comment_string.encode('utf-8') comment_writer.build("32u %db" % (len(comment_string)), (len(comment_string), comment_string)) for page in packet_to_pages( comment_writer.data(), identification_page.bitstream_serial_number, starting_sequence_number=sequence_number): new_ogg.write(page) sequence_number += 1 #transfer remaining pages after re-sequencing page = original_ogg.read_page() page.sequence_number = sequence_number sequence_number += 1 new_ogg.write(page) while (not page.stream_end): page = original_ogg.read_page() page.sequence_number = sequence_number sequence_number += 1 new_ogg.write(page) original_ogg.close() new_ogg.close()
def update_metadata(self, metadata): """takes this track's current MetaData object as returned by get_metadata() and sets this track's metadata with any fields updated in that object raises IOError if unable to write the file """ import os from audiotools import TemporaryFile from audiotools.ogg import (PageReader, PacketReader, PageWriter, packet_to_pages, packets_to_pages) from audiotools.vorbiscomment import VorbisComment from audiotools.bitstream import BitstreamRecorder if (metadata is None): return elif (not isinstance(metadata, VorbisComment)): from .text import ERR_FOREIGN_METADATA raise ValueError(ERR_FOREIGN_METADATA) elif (not os.access(self.filename, os.W_OK)): raise IOError(self.filename) original_ogg = PacketReader(PageReader(file(self.filename, "rb"))) new_ogg = PageWriter(TemporaryFile(self.filename)) sequence_number = 0 #transfer current file's identification packet in its own page identification_packet = original_ogg.read_packet() for (i, page) in enumerate(packet_to_pages( identification_packet, self.__serial_number__, starting_sequence_number=sequence_number)): page.stream_beginning = (i == 0) new_ogg.write(page) sequence_number += 1 #discard the current file's comment packet comment_packet = original_ogg.read_packet() #generate new comment packet comment_writer = BitstreamRecorder(True) comment_writer.build("8u 6b", (3, "vorbis")) vendor_string = metadata.vendor_string.encode('utf-8') comment_writer.build("32u %db" % (len(vendor_string)), (len(vendor_string), vendor_string)) comment_writer.write(32, len(metadata.comment_strings)) for comment_string in metadata.comment_strings: comment_string = comment_string.encode('utf-8') comment_writer.build("32u %db" % (len(comment_string)), (len(comment_string), comment_string)) comment_writer.build("1u a", (1,)) # framing bit #transfer codebooks packet from original file to new file codebooks_packet = original_ogg.read_packet() for page in packets_to_pages( [comment_writer.data(), codebooks_packet], self.__serial_number__, starting_sequence_number=sequence_number): new_ogg.write(page) sequence_number += 1 #transfer remaining pages after re-sequencing page = original_ogg.read_page() page.sequence_number = sequence_number sequence_number += 1 new_ogg.write(page) while (not page.stream_end): page = original_ogg.read_page() page.sequence_number = sequence_number page.bitstream_serial_number = self.__serial_number__ sequence_number += 1 new_ogg.write(page) original_ogg.close() new_ogg.close()