I did not test device but I can explain my case : My customer has mobile video content site. If user's mobile device supported, user can play 3gpp video. By "play video" we mean that we send content-type header and write out file contents with PHP. Before playing 3gpp video, php checks mobile device...

For Samsung GT-C3303, playback_3gpp is false and streaming_3gpp is true. What is the difference?

User-agent : SAMSUNG-GT-C3303i/C3303iJVKB1 NetFront/3.5 Profile/MIDP-2.0 Configuration/CLDC-1.1