RTSP Stack implementation

Question

Hi, I am working on making RTSP url to work on Android.

1. I have used MediaPlayer and VideoView to play the RTSP url but both of them fail to play in G1 Device and emulator. Error is PVMFFailureiin PLAYER_INIT.

2. So I thought of implementing a RTSP client from scratch. I have developed a small application, it exchanges all the messages (DESCRIBE, SETUP, PLAY, TEARDOWN). But the problem is after PLAY, I should receive the RTP packets at client_port as mentioned in Transport header but TCP dump shows the following messages. I think UDP packets are coming but not received at the application.

11:38:50.213394 IP ew-in-f177.google.com.6970 > 192.168.1.2.6970: UDP, length 444 11:38:50.213451 IP 192.168.1.2 > ew-in-f177.google.com: ICMP 192.168.1.2 udp port 6970 unreachable, length 36

Please let me know how to solve this issue.

Answer 1

OpenCORE, the multimedia engine in Android, is rather stringent about sticking to various standards. Some things that may work in the wild (e.g., MP3 over RTSP) are not supported because they are not in the respective spec. Leastways, that's what we have been told.

Hence, it may be that the media you are trying to stream is slightly out of spec, or the server is slightly out of spec. You may wish to try to find some RTSP stream known to work on Android, get your player working right using it, then focus on getting it to consume your own streams.

Answer 2

Some handsets (I don't know whether Android falls in this category or not) include a firewall on the device. In order to receive packets you may have to perform a hole punch (i.e. send a dummy packet to the server. This will create an allow rule on a firewall running on the local device. It will also create the appropriate NAT mapping if necessary as well.)

Is the device on WIFI or on the carrier's network (which carrier)?