A time code to byte conversion system is provided herein that maps time codes to byte ranges such that a user device can retrieve a portion of, but not all of, a media file by specifying a time range. For example, the time code to byte conversion system can play a media file and identify the byte at which each time code begins. The time code to byte conversion system can then store the byte to time code mapping in an index accessible by a media retrieval server. A user device can then provide a time range to the media retrieval server, the media retrieval server can query the index to identify the range of bytes that corresponds to the provided time range, and then the media retrieval server can retrieve the identified range of bytes from a media database for transmission to the user device.