[FFmpeg-user] random stream ids from mpeg2 multicast source

[Sinan Alyuruk]

Hi,

I am trying to record a channel from mpeg2 multicast stream. Stream 
mapping returns inconsistently whenever I run ffmpeg  to inspect the 
required streams .

ffmpeg -i udp://@225.100.100.100:1234

First run:

   Program 1101
     Metadata:
       service_name    : ?KANAL D
       service_provider: ?DOGAN TV
     Stream #0:17[0x65]: Video: mpeg2video (Main) ([2][0][0][0] / 
0x0002), yuv420p(tv), 720x576 [SAR 64:45 DAR 16:9], max. 15000 kb/s, 25 
fps, 25 tbr, 90k tbn, 50 tbc
     Stream #0:18[0xc9](tur): Audio: mp2 ([4][0][0][0] / 0x0004), 48000 
Hz, stereo, s16p, 256 kb/s
     Stream #0:2[0x1023]: Unknown: none ([11][0][0][0] / 0x000B)

Second run:

   Program 1101
     Metadata:
       service_name    : ?KANAL D
       service_provider: ?DOGAN TV
     Stream #0:13[0x65]: Video: mpeg2video (Main) ([2][0][0][0] / 
0x0002), yuv420p(tv), 720x576 [SAR 64:45 DAR 16:9], max. 15000 kb/s, 25 
fps, 25 tbr, 90k tbn, 50 tbc
     Stream #0:33[0xc9](tur): Audio: mp2 ([4][0][0][0] / 0x0004), 48000 
Hz, stereo, s16p, 256 kb/s
     Stream #0:23[0x1023]: Unknown: none ([11][0][0][0] / 0x000B)

Third run:
   Program 1101
     Metadata:
       service_name    : ?KANAL D
       service_provider: ?DOGAN TV
     Stream #0:27[0x65]: Video: mpeg2video (Main) ([2][0][0][0] / 
0x0002), yuv420p(tv), 720x576 [SAR 64:45 DAR 16:9], max. 15000 kb/s, 25 
fps, 25 tbr, 90k tbn, 50 tbc
     Stream #0:28[0xc9](tur): Audio: mp2 ([4][0][0][0] / 0x0004), 48000 
Hz, stereo, s16p, 256 kb/s
     Stream #0:13[0x1023]: Unknown: none ([11][0][0][0] / 0x000B)


Like this example on every run returns the Stream # differently. So how 
can I pick a correct stream for recording according to this output?

All I want to do is record the stream like that:
ffmpeg -i udp://@225.100.100.100:1234  -map 0:17 -map 0:18 -c:v copy -f 
mpeg output.mpg

I am using:
ffmpeg version git-2014-12-01-928322c


Regards,
Sinan