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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 starting manually but not with Systemd on boot

  23 juin 2021, par eKrajnak

  On Raspberry Pi 4 B 4GB with official Debian 10 image, I have /home/pi/run.sh script with following :

  


  #!/bin/bash
ffmpeg -nostdin -framerate 15 -video_size 1280x720 -input_format yuyv422  -i /dev/video0 -f alsa -i hw:Device \
    -af acompressor=threshold=-14dB:ratio=9:attack=10:release=1000 -c:a aac -ac 2 -ar 48000 -ab 160k \
    -c:v libx264 -pix_fmt yuv420p -b:v 3M -bf 1 -g 20 -flags +ilme+ildct -preset ultrafast \
    -streamid 0:0x101 -streamid 1:0x100 -mpegts_pmt_start_pid 4096 -mpegts_start_pid 0x259 -metadata:s:a:0 language="" -mpegts_service_id 131 -mpegts_transport_stream_id 9217 -metadata provider_name="Doesnt matter" -metadata service_name="Doesnt matter" \
    -minrate 3500 -maxrate 3500k -bufsize 4500k -muxrate 4000k  -f mpegts "udp://@239.1.67.13:1234?pkt_size=1316&bitrate=4000000&dscp=34" -loglevel debug < /dev/null > /tmp/ff3.log 2>&1


  


  Script is starting from console without problems. It takes audio from USB sound card and video from USB camera and creates UDP stream to IPTV. Then I created Systemd service :

  


  [Unit]
Description=Streamer
After=multi-user.target sound.target network.target

[Service]
ExecStart=/home/pi/run.sh
KillMode=control-group
Restart=on-failure
TimeoutSec=1

[Install]
WantedBy=multi-user.target
Alias=streaming.service


  


  After restarting Raspberry, script has started, but FFmpeg hangs on error failures in log :

  


  cur_dts is invalid st:0 (257) [init:1 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
cur_dts is invalid st:1 (256) [init:1 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
cur_dts is invalid st:0 (257) [init:1 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
cur_dts is invalid st:1 (256) [init:1 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
cur_dts is invalid st:0 (257) [init:1 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
cur_dts is invalid st:1 (256) [init:1 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
cur_dts is invalid st:0 (257) [init:1 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
cur_dts is invalid st:1 (256) [init:1 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)


  


  and will not start streaming to UDP target. But, if I manually login to SSH and issue systemctl stop streaming and then systemctl start streaming Ffmpeg starts successfully. What's different with service auto-start on boot ?

  


  Setting the "sleep timeout" at script begginging will not help. However, removing audio stream from FFmpeg config looks to solve auto-start on boot.

  


• Pass embedded closed captions with FFmpeg

  4 décembre 2020, par Andrew

  I am taking an HLS stream and outputting it through a DeckLink card to convert it to SDI. I need to pass the CEA-708 closed captions that are embedded in the stream, and it has to happen live. This is the command I'm currently using :

  



  ffmpeg.exe -loglevel info -re -i https://my-url.m3u8 -c:v wrapped_avframe -pix_fmt uyvy422 -vf scale=1280x720 -c:a pcm_s16le -ar 48000 -ac 2 -f decklink -s 1280x720 -r 60000/1001 -b:v 4M "DeckLink SDI (2)"

  



  I have tried adding the -teletext all command to no avail.

  



  Here is the output of FFprobe :

  



  Input #0, hls, from 'https://my-url.m3u8':
  Duration: N/A, start: 83023.890600, bitrate: N/A
  Program 0
    Metadata:
      variant_bitrate : 998000
    Stream #0:0: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(progressive), 640x360, Closed Captions, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
    Metadata:
      variant_bitrate : 998000
    Stream #0:1(eng): Audio: aac (LC) ([15][0][0][0] / 0x000F), 44100 Hz, stereo, fltp, 158 kb/s (default)
    Metadata:
      variant_bitrate : 998000
      comment         : Master Audio
    Stream #0:2: Data: timed_id3 (ID3  / 0x20334449)
    Metadata:
      variant_bitrate : 998000
  Program 1
    Metadata:
      variant_bitrate : 658000
    Stream #0:3: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(progressive), 480x270, Closed Captions, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
    Metadata:
      variant_bitrate : 658000
    Stream #0:4(eng): Audio: aac (LC) ([15][0][0][0] / 0x000F), 44100 Hz, stereo, fltp, 158 kb/s (default)
    Metadata:
      variant_bitrate : 658000
      comment         : Master Audio
    Stream #0:5: Data: timed_id3 (ID3  / 0x20334449)
    Metadata:
      variant_bitrate : 658000
  Program 2
    Metadata:
      variant_bitrate : 1958000
    Stream #0:6: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(progressive), 960x540, Closed Captions, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
    Metadata:
      variant_bitrate : 1958000
    Stream #0:7(eng): Audio: aac (LC) ([15][0][0][0] / 0x000F), 44100 Hz, stereo, fltp, 158 kb/s (default)
    Metadata:
      variant_bitrate : 1958000
      comment         : Master Audio
    Stream #0:8: Data: timed_id3 (ID3  / 0x20334449)
    Metadata:
      variant_bitrate : 1958000
  Program 3
    Metadata:
      variant_bitrate : 2658000
    Stream #0:9: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(progressive), 1280x720, Closed Captions, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
    Metadata:
      variant_bitrate : 2658000
    Stream #0:10(eng): Audio: aac (LC) ([15][0][0][0] / 0x000F), 44100 Hz, stereo, fltp, 158 kb/s (default)
    Metadata:
      variant_bitrate : 2658000
      comment         : Master Audio
    Stream #0:11: Data: timed_id3 (ID3  / 0x20334449)
    Metadata:
      variant_bitrate : 2658000
Unsupported codec with id 100358 for input stream 2
Unsupported codec with id 100358 for input stream 5
Unsupported codec with id 100358 for input stream 8
Unsupported codec with id 100358 for input stream 11


  



  As you can see, closed captions are embedded in each of the VBR streams, but are getting stripped during the transcode to SDI. How can I pass these to view them ?