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• Anomalie #3227 : Bug date de publication

  17 septembre 2014, par 毎日 erational -

  quelqu’un sur le forum http://forum.spip.net/fr_258722.html signale une erreur de type avec le mktime

• FFmpeg Dropping Aspect Ratio on FLV Output

  16 septembre 2017, par Mike B

  I am having an issue with FFmpeg dropping the aspect ratio when converting a 1920x1080 stream to a lower resolution (please see below for more information). The objective is to take the output from TVHeadend and convert it to a FLV format that I can stream outside of my house.

  ffmpeg -c:v mpeg2_mmal -i http://192.168.1.142:9981/stream/channelnumber/10.1?profile=pass -c:a libfdk_aac -profile:a aac_he_v2 -b:a 32k -ac 2 -async 48000 -c:v h264_omx -b:v 1800k -sws_flags fast_bilinear -vf scale=720:540 -keyint_min 0 -g 100 -f flv rtmp://192.168.1.110:1935/live/test

  This produces the following onscreen output :

  Output #0, flv, to 'rtmp://192.168.1.110:1935/live/test':
  
    Metadata:
  
      encoder         : Lavf57.82.100
  
      Stream #0:0: Video: h264 (h264_omx) ([7][0][0][0] / 0x0007), yuv420p, 720x540 [SAR 4:3 DAR 16:9], q=2-31, 1800 kb/s, 29.97 fps, 1k tbn, 29.97 tbc
  
      Metadata:
  
        encoder         : Lavc57.105.100 h264_omx
  
      Stream #0:1(eng): Audio: aac (libfdk_aac) (HE-AACv2) ([10][0][0][0] / 0x000A), 48000 Hz, stereo, s16, 32 kb/s
  
      Metadata:
  
        encoder         : Lavc57.105.100 libfdk_aac

  Based on the onscreen output, it appears that that SAR and DAR are correct. It is only when you examine the actual files that the aspect ratio has been dropped.

  Input #0, hls,applehttp, from 'http://192.168.1.110:8080/live/test/index.m3u8':
  
    Duration: N/A, start: 109.116000, bitrate: N/A
  
    Program 0 
  
      Metadata:
  
        variant_bitrate : 0
  
      Stream #0:0: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p, 720x540, 29.97 tbr, 90k tbn, 180k tbc
  
      Metadata:
  
        variant_bitrate : 0
  
      Stream #0:1: Audio: aac (HE-AACv2) ([15][0][0][0] / 0x000F), 48000 Hz, stereo, fltp
  
      Metadata:
  
        variant_bitrate : 0

  I modified the command to instead save to a local MP4 file :

  ffmpeg -c:v mpeg2_mmal -i http://192.168.1.142:9981/stream/channelnumber/10.1?profile=pass -c:a libfdk_aac -profile:a aac_he_v2 -b:a 32k -ac 2 -async 48000 -c:v h264_omx -b:v 1800k -sws_flags fast_bilinear -vf scale=720:540 -keyint_min 0 -g 100 ~/test.mp4

  And the issue is resolved. I have also tried adding the video filters setsar and setdar to no avail.

  I am performing this on a Raspberry Pi 3, which lacks the ability to de-interlace in hardware. To remedy this, I am simply scaling the video vertically by 1/2. I have tried scaling the output to 960x540 but the Pi has issues keeping up.

• Simples loop to iterate over files and send them to ffmpeg

  25 octobre 2019, par user2752471

  I want to do a shell script that will iterate over several video files in a directory, send everyone of them to ffmpeg, that will then reencode each one, producing a reencoded file that will have the same name as the original, except with .avi extension instead .mkv or .mp4.

  I found a fairly simple script in another topic here on SO, tried to change it slightly to take into account the file extension and the destination directory.

  However my script only produces countless "anything : No such file or directory"

  Here is it :

  $ for f in $(find -type f -name *.mkv); do ffmpeg -n -i "$f" -c:v copy ".$f" ; done

  And these is the ffmpeg command that I usually use :

  ffmpeg -y -i  -vf scale=720:-2 -c:v mpeg4 -vtag xvid -b:v 969k -pass 1 -an -f avi /dev/null && ffmpeg -i -c:a libmp3lame -b:a 48k -ac 1 -vf scale=720:-2 -c:v mpeg4 -vtag xvid -b:v 969k -pass 2  .avi

  So I need to identify what is incorrect in the first script, that is considering each small word of the file’s name as a file, and then change it as to add all these ffmpeg parameters.

  Somethings that I do not understand in the script :

  1)Are the -type and f in find command necessary. From what I read of the documentation, all it does is to tell find that it shall look for normal files, something that seems irrelevant for my case. When I use find, I do : find starting dir -name filename. So do I have to keep it ?

  2)What -n means for ffmpeg ? I am currently without a man entry for ffmpeg. Is it necessary for my needs ?

  3)Do I need to have "" around $f ? What it does ?

  4)As far as I understand $ denotes a variable. But what the "f" after it does ? Do I need it ?

  5)The " ;" after the closing ")" and the ".$f" are necessary ? The first is used to indicate the end of the for loop,and the second the end of the ffmpeg command ?

  6)The "do" and the "does" are also necessary for the same motives behind the " ;"

  Here is my attempt of the ffmpeg part of the script. Please tell me what to change on it, as in the find part of it.

  do ffmpeg -n -y -i "$f.mkv" -vf scale=720:-2 -c:v mpeg4 -vtag xvid -b:v 969k -pass 1 -an -f avi /dev/null && ffmpeg -n -i "$f" -c:a libmp3lame -b:a 48k -ac 1 -vf scale=720:-2 -c:v mpeg4 -vtag xvid -b:v 969k -pass 2  ".$f.avi" ; done

  If I would like the script to also look for ".mp4" besides ".mkv" how I would need to change it ?

  Thanks for any input.