[FFmpeg-trac] #9102(undetermined:new): make HLS from multicast with ac3 audio track which have 0 channels

FFmpeg trac at avcodec.org
Fri Feb 12 07:43:24 EET 2021

#9102: make HLS from multicast with ac3 audio track which have 0 channels
             Reporter:  krs_vital    |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:  git-
  undetermined                       |  master
             Keywords:  ac3          |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
 I want to make HLS with stream determined like this:

 [mpegts @ 0x2635780] Could not find codec parameters for stream 3 (Audio:
 ac3 (AC-3 / 0x332D4341), 0 channels, fltp): unspecified sample rate
 Consider increasing the value for the 'analyzeduration' (25000000) and
 'probesize' (25000000) options
 Input #0, mpegts, from 'udp://':
   Duration: N/A, start: 42075.039333, bitrate: N/A
   Program 17104
       service_name    : VIP Premiere
       service_provider: HTB+
     Stream #0:1[0x130]: Video: h264 (High) ([27][0][0][0] / 0x001B),
 yuv420p(tv, bt709, top first), 1920x1080 [SAR 1:1 DAR 16:9], 25 fps, 50
 tbr, 90k tbn, 50 tbc
     Stream #0:2[0x194](rus): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz,
 stereo, fltp, 192 kb/s
     Stream #0:3[0x1a8](rus): Audio: ac3 (AC-3 / 0x332D4341), 0 channels,
     Stream #0:4[0x1f8](rus): Subtitle: dvb_subtitle ([6][0][0][0] /

 but ffmpeg stops and do nothing.

 sometimes in this stream on audio track [Stream #0:3] appears bitrate when
 TV provider make it, but sometimes this audio track is empty.This usually
 happens when content with 5.1 sound is turned on and then this track is
 not empty.

 How to make ffmpeg automatically detect the audio track on the fly and
 start working with it, since during decoding it can be empty or not?

 Ffmpeg starts like this:

 /usr/local/bin/ffmpeg -analyzeduration 25000000 -probesize 25000000
 -dts_delta_threshold 3600 -err_detect ignore_err -correct_ts_overflow 0
 -copytb 1 -overrun_nonfatal 1 -i udp:// -y -sn -dn -c:v
 copy -c:a aac -vsync 1 -hls_time 10 -map 0 -ignore_unknown -strftime 1
 -strftime_mkdir 1 -max_interleave_delta 360000000000 -hls_flags
 omit_endlist -hls_segment_filename
 /store/records/Premium/%Y/%m/%d/%H/%s.ts /hls/tmp/Premium.m3u8

Ticket URL: <https://trac.ffmpeg.org/ticket/9102>
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