A streaming media processing method, a transmitting device and a receiving device are provided. The streaming media processing method includes the following steps: encoding original media data into encoded streaming media; adding metadata to a media frame in the encoded streaming media to generate a padded streaming media, and the metadata serves as a payload data of the media frame; and encapsulating the padded streaming media into a streaming media packet. In this way, it is possible to satisfy the requirement of compatibility without affecting codec and communication protocols.