利用ffmpeg取出ts流中特定的program

https://trac.ffmpeg.org/wiki/Map

Example 8

MPEG stream selection:

The tricky part with selecting from MPEG TS is it may contain multiple streams/channels, and if you are receiving "live data" just specifying an index might not work because it can change from run to run, so

ffmpeg -i INPUT -map 0:6 OUTPUT # might not work the same every run, DO NOT USE THIS WAY!

Assuming your file is MPEG, you can run "ffmpeg -i INPUT" (not specify an output) to see what program id's and stream id's it contains, like this example (probesize and analyzeduration specified to help "make sure" it picks up all the streams in it, may not be always needed)

$ ffmpeg -probesize 50M -analyzeduration 50M -i INPUT
...
Input #0, mpegts, from 'INPUT':
  Duration: N/A, start: 22159.226833, bitrate: N/A
  Program 1344
    Metadata:
      service_name    : 7 Digital
      service_provider: Seven Network
    Stream #0:0[0x401]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002), yuv420p(tv), 720x576 [SAR 64:45 DAR 16:9], max. 14950 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
    Stream #0:1[0x402](eng): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, s16p, 256 kb/s
  Program 1346
    Metadata:
      service_name    : 7TWO
      service_provider: Seven Network
    Stream #0:3[0x406]: Unknown: none ([5][0][0][0] / 0x0005)
    Stream #0:6[0x421]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002), yuv420p(tv), 720x576 [SAR 64:45 DAR 16:9], max. 14950 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
    Stream #0:7[0x422](eng): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, s16p, 192 kb/s
    Stream #0:8[0x424](eng): Subtitle: dvb_teletext ([6][0][0][0] / 0x0006), 492x250
    Stream #0:4[0x499]: Unknown: none ([11][0][0][0] / 0x000B)

you could specify desired streams by program id:

ffmpeg -i INPUT -map 0:p:1344 OUTPUT # pulls in both inputs from program 1344, channel "7 Digital" in this case

or specify a child stream:

ffmpeg -i INPUT -map i:0x401 OUTPUT # pulls in the single input stream with PID (MPEG Packet ID [stream identifier]) 0x401 from wherever it is found, in this case its a video stream in "7 Digital"

or similar, see other specifier examples. Note if you have "unknown" streams in there you may need to add the -ignore_unknown flag as well.

Also note that if your input stream contains multiple program id's, you can record simultaneously from various of them, using the same FFmpeg instance and the map commands described here.

解決會自動transcode的問題

http://stackoverflow.com/questions/43845382/ffmpeg-retrieve-a-specific-program-from-ts-file/43846235#43846235

FFmpeg, by default, will transcode to the default codecs for the output container. Add -codec copyor -c copy i.e.

ffmpeg -i INPUT -c copy -map 0:p:1344 OUTPUT