Methods, systems, and apparatus, including computer programs encoded on computer storage media, for encoding binary data are provided. One of the methods includes: obtaining a multimedia file from a storage device, extracting multiple bytes of binary data from the multimedia file, converting the binary data into 7-bit encoded data using an encoding algorithm, and sending one or more signals comprising the 7-bit encoded data to a remote computing device. The converting includes identifying multiple bits of data, each corresponding to a predetermined bit position of one of the bytes of binary data, generating one or more bytes of combined-bit data by combining the identified bits of data, generating one or more bytes of remaining-bit data, and generating the 7-bit encoded data by concatenating the one or more bytes of combined-bit data and the one or more bytes of remaining-bit data.