[fix] SDP parsing issue

[minwinmin]

Description

I used a network camera without audio interface.
However, sample app for rtsp-client-android was unable to stream video.

The cause is the failure to parse a SDP line regarding audio.

Problem

I used my network camera, then I can acquire SDP lines below.

[Pair{v 0}, 
Pair{o - 294741794 1 IN IP4 192.168.0.0}, 
Pair{s IGCSMS}, Pair{i }, Pair{t 0 0}, 
Pair{a tool:IGCSMS}, 
Pair{m video 0 RTP/AVP 96}, 
Pair{c IN IP4 192.168.0.0}, 
Pair{b AS:2},
Pair{a rtpmap:96 H264/90000}, 
Pair{a fmtp:96 packetization-mode=1;profile-level-id=64001E;sprop-parameter-sets=Z2QAHqwsaoKAv+WbgICAgQ==,aO4xshs=}, 
Pair{a control:track=1}, 
Pair{m audio 0 RTP/AVP (null)}, 
Pair{c IN IP4 0.0.0.0}, 
Pair{b AS:64}, 
Pair{a rtpmap}, 
Pair{a control:track=2}]

And this line including "(null)" is problem.

Pair{m audio 0 RTP/AVP (null)}, 

The original code cannot parse this line properly.

Changes

I added a exception handling.

if (currentTrack != null) {
    // m=<media> <port>/<number of ports> <proto> <fmt> ...
    String[] values = TextUtils.split(param.second, " ");
    // add this line ↓
    try{
        currentTrack.payloadType = (values.length > 3 ? Integer.parseInt(values[3]) : -1);
    }catch (Exception e){
        currentTrack.payloadType = -1;
    }
    if (currentTrack.payloadType == -1)
    Log.e(TAG, "Failed to get payload type from \"m=" + param.second + "\"");
}

[alexeyvasilyev]

Thanks for PR!