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• ffmpeg to dvb-c. Need some advices

  12 octobre 2017, par pentarhh

  I’d like to get some advices about ffmpeg transcoding and broadcasting it to DVB-C environment.
  Have a server, based on Linux with external GPUs based on Nvidia P4000. Target of this machine is getting live streams at HLS, then it transcode files to multicast UDP. After transcoding multicast TS gets to receiver (Sumavision EMR 3.0), then modulates into DVB-C with QAM-card for next transmission to fiber.

  So, there is a strange trouble. In IPTV such stream have no visible troubles. Analyzing TS, saw an errors with PCR accuracy (>500 ms ’cause of pseudo-CBR) and very rare discontinuity errors, that could be based on source errors.
  Then I take it to Sumavision and apply inbound parameters (just remultiplexing this stream with making loyal reference, buffer size values and CBR output values). Analyzer sees no problem, after putting in QAM-modulator customize output streams, such as PSI/SI tables, frequency, symbol rate etc.

  After I see the result at some test TVs. First one shows this channel great, with no visible troubles (no artefacts, no asynchronous sound). Second TV has a problem of video, it looks like a lost frames. Sometimes sound interrupts for a milliseconds. But there is no freezes
  ’Cause of ETR 101 290 passes well, may be this model of TV decodes this service incorrect. Example of video record is here.

  Here is the code of ffmpeg. May be, I missed some common parameters, that may get the output is better for such tuners. Can you see it’s alright ?

  sudo -u nobody ffmpeg -threads 0 -v warning -re -hwaccel cuvid -hwaccel_device 2 -c:v h264_cuvid -deint 0 -i http://x.x.x.x/playlist.m3u8 -bsf:v h264_mp4toannexb -map 0:0 -map 0:1 -vcodec h264_nvenc -gpu 2 -cbr true -sc_threshold 0 -filter:v scale_npp=960:540:interp_algo=lanczos -vprofile baseline -b:v 1000k -bufsize 1400k -maxrate 1400k -minrate 900k -force_key_frames 1 -g 50 -bf 0 -refs 1 -r 25 -strict experimental -c:a aac -b:a 64K -af aresample=44100 -ac 2 -flags -global_header -f segment -segment_format mpegts -segment_time 10 /path1/segment-1507744758-%06d.ts -map 0:0 -map 0:1 -vcodec h264_nvenc -gpu 2 -cbr true -sc_threshold 0 -vprofile high -b:v 8000k -bufsize 400k -maxrate 9000k -minrate 7200k -force_key_frames 1 -g 50 -bf 2 -refs 1 -r 25 -strict experimental -c:a aac -b:a 192K -af aresample=44100 -ac 2 -flags -global_header -f tee 
  
  [f=segment:segment_format=mpegts:segment_time=10]/path2/segment-1507744758-%06d.ts|[f=mpegts:muxrate=9333k:mpegts_pmt_start_pid=0xB4A:mpegts_start_pid=0xB4B]'udp://y.y.y.y:1234?buffer_size=0&overrun_nonfatal_option=1&pkt_size=1316&ttl=15'

• ffmpeg to dvb-c. Need some advices

  12 octobre 2017, par pentarhh

  I’d like to get some advices about ffmpeg transcoding and broadcasting it to DVB-C environment.
  Have a server, based on Linux with external GPUs based on Nvidia P4000. Target of this machine is getting live streams at HLS, then it transcode files to multicast UDP. After transcoding multicast TS gets to receiver (Sumavision EMR 3.0), then modulates into DVB-C with QAM-card for next transmission to fiber.

  So, there is a strange trouble. In IPTV such stream have no visible troubles. Analyzing TS, saw an errors with PCR accuracy (>500 ms ’cause of pseudo-CBR) and very rare discontinuity errors, that could be based on source errors.
  Then I take it to Sumavision and apply inbound parameters (just remultiplexing this stream with making loyal reference, buffer size values and CBR output values). Analyzer sees no problem, after putting in QAM-modulator customize output streams, such as PSI/SI tables, frequency, symbol rate etc.

  After I see the result at some test TVs. First one shows this channel great, with no visible troubles (no artefacts, no asynchronous sound). Second TV has a problem of video, it looks like a lost frames. Sometimes sound interrupts for a milliseconds. But there is no freezes
  ’Cause of ETR 101 290 passes well, may be this model of TV decodes this service incorrect. Example of video record is here.

  Here is the code of ffmpeg. May be, I missed some common parameters, that may get the output is better for such tuners. Can you see it’s alright ?

  sudo -u nobody ffmpeg -threads 0 -v warning -re -hwaccel cuvid -hwaccel_device 2 -c:v h264_cuvid -deint 0 -i http://x.x.x.x/playlist.m3u8 -bsf:v h264_mp4toannexb -map 0:0 -map 0:1 -vcodec h264_nvenc -gpu 2 -cbr true -sc_threshold 0 -filter:v scale_npp=960:540:interp_algo=lanczos -vprofile baseline -b:v 1000k -bufsize 1400k -maxrate 1400k -minrate 900k -force_key_frames 1 -g 50 -bf 0 -refs 1 -r 25 -strict experimental -c:a aac -b:a 64K -af aresample=44100 -ac 2 -flags -global_header -f segment -segment_format mpegts -segment_time 10 /path1/segment-1507744758-%06d.ts -map 0:0 -map 0:1 -vcodec h264_nvenc -gpu 2 -cbr true -sc_threshold 0 -vprofile high -b:v 8000k -bufsize 400k -maxrate 9000k -minrate 7200k -force_key_frames 1 -g 50 -bf 2 -refs 1 -r 25 -strict experimental -c:a aac -b:a 192K -af aresample=44100 -ac 2 -flags -global_header -f tee 
  
  [f=segment:segment_format=mpegts:segment_time=10]/path2/segment-1507744758-%06d.ts|[f=mpegts:muxrate=9333k:mpegts_pmt_start_pid=0xB4A:mpegts_start_pid=0xB4B]'udp://y.y.y.y:1234?buffer_size=0&overrun_nonfatal_option=1&pkt_size=1316&ttl=15'

• How to get full name of default microphone ?

  9 août 2019, par Jiapeng Li

  Been trying to get full name of microphone as a variable on Python for usage of ffmpeg. I have already tried

  p = pyaudio.PyAudio()
  
  default_device = p.get_default_input_device_info()
  
  print(default_device['name'])

  and here was the output :

  Microphone (Conexant SmartAudio         #it was truncated to 31 characters length

  Obviously,that was truncated and not what i wanted.
  Tried sounddevice too :

  import sounddevice as sd
  
  s = sd.query_devices()
  
  print(s)

  Output :

     0 Microsoft Sound Mapper - Input, MME (2 in, 0 out)
  
  >  1 Microphone (Conexant SmartAudio, MME (2 in, 0 out)           #still truncated
  
     2 Microsoft Sound Mapper - Output, MME (0 in, 2 out)
  
  <  3 Speakers (Conexant SmartAudio H, MME (0 in, 2 out)
  
     4 Primary Sound Capture Driver, Windows DirectSound (2 in, 0 out)
  
     5 Microphone (Conexant SmartAudio HD), Windows DirectSound (2 in, 0 out)    #now got normal,but why?
  
     6 Primary Sound Driver, Windows DirectSound (0 in, 2 out)
  
     7 Speakers (Conexant SmartAudio HD), Windows DirectSound (0 in, 2 out)
  
     8 Speakers (Conexant SmartAudio HD), Windows WASAPI (0 in, 2 out)
  
     9 Microphone (Conexant SmartAudio HD), Windows WASAPI (2 in, 0 out)
  
    10 Stereo Mix (Conexant HD Stereo Mix), Windows WDM-KS (2 in, 0 out)
  
    11 Microphone (Conexant HD Audio capture), Windows WDM-KS (2 in, 0 out)
  
    12 Speakers (Conexant HD Audio output), Windows WDM-KS (0 in, 2 out)

  It can be seen that device number 1 was my default one and if that was full name it would be perfect but unfortunately that was not.

  Then the only thing i could have thought of was to capture full name from list that ffmpeg provided :

  'ffmpeg -list_devices true -f dshow -i dummy':
  
  [dshow @ 000001cc4f298d00] DirectShow video devices (some may be both video and audio devices)
  
  [dshow @ 000001cc4f298d00]  "USB2.0 VGA UVC WebCam"
  
  [dshow @ 000001cc4f298d00]     Alternative name "@device_pnp_\\?\usb#vid_13d3&pid_5a07&mi_00#6&2f27e633&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global"
  
  [dshow @ 000001cc4f298d00]  "screen-capture-recorder"
  
  [dshow @ 000001cc4f298d00]     Alternative name "@device_sw_{860BB310-5D01-11D0-BD3B-00A0C911CE86}\{4EA69364-2C8A-4AE6-A561-56E4B5044439}"
  
  [dshow @ 000001cc4f298d00] DirectShow audio devices
  
  [dshow @ 000001cc4f298d00]  "Microphone (Conexant SmartAudio HD)"
  
  [dshow @ 000001cc4f298d00]     Alternative name "@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\wave_{AFE404CD-A721-49BE-8AC5-669DA725185F}"
  
  [dshow @ 000001cc4f298d00]  "virtual-audio-capturer"
  
  [dshow @ 000001cc4f298d00]     Alternative name "@device_sw_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\{8E146464-DB61-4309-AFA1-3578E927E935}"

  I used

  popen = subprocess.Popen('ffmpeg -list_devices true -f dshow -i dummy', stdout=subprocess.PIPE)
  
  popen.wait()
  
  
  
  lines = popen.stdout.readlines()
  
  print(lines)

  After that i got totally confused because the output was an empty list. Now i am lost in desert and know nowhere to go. Really appreciate it if you could help.