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• ffmpeg errors in the daemon

  3 octobre 2020, par smoto_shei

  I created a shell script to compress a video using ffmpeg(4.3.1).

  


  ffmpeg -y -i \
 '/var/www/System/Backend/Outputs/TempSaveMovie/200703_4_short_5fr_p2(100_20)_r(50_20).mp4' \
 -vcodec h264 -an \
 '/var/www/System/Backend/Outputs/MovieOutputs/200703_4_short_5fr_p2(100_20)_r(50_20).mp4'



  


  If you run this code from the console, it will run without problems.
In fact, we're using the python subscript.call() to execute it. It works fine too.

  


  cmd = 'sh /var/www/System/Backend/cv2toffmpeg.sh'
subprocess.call(cmd, shell=True)


  


  Secondly, if I run it from a daemonized python program, I'll get an error. I get the following error.
You'll get an error like this

  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from './Outputs/TempSaveMovie/200703_4_short_5fr_p2(100_20)_r(50_20).mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2mp41
    encoder         : Lavf58.35.100
  Duration: 00:00:06.15, start: 0.000000, bitrate: 10246 kb/s
    Stream #0:0(und): Video: mpeg4 (Simple Profile) (mp4v / 0x7634706D), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 10244 kb/s, 13 fps, 13 tbr, 13312 tbn, 13 tbc (default)
    Metadata:
      handler_name    : VideoHandler
Stream mapping:
  Stream #0:0 -> #0:0 (mpeg4 (native) -> h264 (h264_nvenc))
Press [q] to stop, [?] for help
[mpeg4 @ 0x55cec17c5480] header damaged
[mpeg4 @ 0x55cec17c6840] header damaged
[mpeg4 @ 0x55cec1855f80] header damaged
[mpeg4 @ 0x55cec1866e00] header damaged
Output #0, mp4, to './Outputs/MovieOutputs/200703_4_short_5fr_p2(100_20)_r(50_20).mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2mp41
    encoder         : Lavf58.45.100
    Stream #0:0(und): Video: h264 (h264_nvenc) (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 2000 kb/s, 13 fps, 13312 tbn, 13 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      encoder         : Lavc58.91.100 h264_nvenc
    Side data:
      cpb: bitrate max/min/avg: 0/0/2000000 buffer size: 4000000 vbv_delay: N/A
Error while decoding stream #0:0: Invalid data found when processing input
[mpeg4 @ 0x55cec17c8780] header damaged
Error while decoding stream #0:0: Invalid data found when processing input
[mpeg4 @ 0x55cec17c5480] header damaged


  


  I think the problem is when you run it from a daemonized process. There seems to be a similar problem in the past.
Ffmpeg does not properly convert videos when run as daemon
I would like to ask for your help to solve this problem. Thank you for your help from Japan.

  


• How to compare/show the difference between 2 videos in ffmpeg ?

  25 janvier 2016, par polarka

  I am a newbie at encoding. I have read and tried x264 in lossless mode (-qp 0), however I’d like to make sure that in my new video, every single pixel contains the same information as the source file (which is in YUV 420 so the loss of color conversion is avoidable, as far as I know). I want to be able to check that, because I don’t believe in that if someone just says its lossless.

  I welcome answers suggesting other codecs for lossless encoding, my only requirements for codecs are having one of the best compression rate and let me to pick different calculation times (such as the range from placebo to veryfast in x264) in order to adjust the compression level and calc time to my needs. But keep in mind that the original question is about how can I calculate the differences frame by frame of two videos and export it to a 3rd file, so I can watch it myself. I think that knowledge (if its possible and doesnt have serious limitations) will be useful for me in the future too.

• equivalent option in ffmpeg for ffplay's -infbuff

  25 septembre 2015, par Paul

  I have a multicast UDP stream that I can watch (with almost no errors) if I use ffplay’s infbuf option.

  But when I try to encode it via ffmpeg, ffmpeg reports a lot of errors and the resultant video has lots of errors.

  I have tried setting the fifo_size to a super large value like 655360 and the buf_size as per https://www.ffmpeg.org/ffmpeg-protocols.html#udp. But none of gets rid of the decode errors in ffmpeg.

  Is it possible to provide settings to ffmpeg that do something similar to what ffplay’s -intbuf does ? I want my video encode to be as error free as video playback via ffplay.