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• how to determine the average biterate and peak bitrate of a video using ffmpeg ?

  14 février 2018, par loki

  I don’t understand, when in ffmpeg i do ffmpeg -i <input /> i have :

  Video : hevc (Main) (hev1 / 0x31766568), yuv420p(tv), 1920x1080, 4997 kb/s, 30 fps, 30 tbr, 998795.00 tbn, 30 tbc (default)

  it’s show bitrate : 4997 kb/s BUT the size of the file is 114915563 bytes for a duration of 179 secondes. when i do math i have 114915563 / 179 = 641986 bytes/s = 642 kb/s :(

  What did i miss ? how to retrieve the average bitrate of a movie and the peak bitrate of a movie ?

• FFmpeg capture, mkvtimestamp_v2 and timecode don't play nice

  24 mai 2021, par Bouke

  Trying to capture and modify the TC in-file afterwards.
I've found a nice way to store the timestamps from the capture.
Gyan's brillant filterchain

  


  This works fine using this line :

  


  ffmpeg -hide_banner -f "decklink" -queue_size "1073741824" -raw_format "auto" -format_code "Hi50" -video_input "sdi" -i "bm mini One" -filter_complex "settb=1/1000,setpts=RTCTIME/1000-1500000000000,mpdecimate,split[out][ts];[out]setpts=N/25/TB[out]" -map "[out]" -c:a "copy" -c:v "prores" -profile:v "1" -vendor "ap10" -pix_fmt "yuv422p10le" "/Volumes/Data/tst1.mov" -map "[ts]" -f mkvtimestamp_v2 "/Volumes/Data/time.txt" -vsync 0


  


  But, when I add -timecode "00:00:00:00" (to force a TC atom in the output), horrible things happen.

  


  ffmpeg -f "decklink" -queue_size "1073741824" -raw_format "auto" -format_code "Hi50" -video_input "sdi" -i "bm mini One" -filter_complex "settb=1/1000,setpts=RTCTIME/1000-1500000000000,mpdecimate,split[out][ts];[out]setpts=N/25/TB[out]" -map "[out]" -timecode "00:01:00:00" -c:a "copy" -c:v "prores" -profile:v "1" -vendor "ap10" -pix_fmt "yuv422p10le" "/Volumes/Data/tst1.mov" -map "[ts]" -f mkvtimestamp_v2 "/Volumes/Data/time.txt" -vsync 0


  


  The timecode does not run at the video speed, skips a frame or two here and there, and the image freezes after a random amount of time (between 10 seconds and a minute or so).

  


  How come the timecode can mess up stuff that much ? From what I understand it's just a couple of atoms in the moov atom, and a reference where the actual TC value (as frames) is stored in the mdat.

  


  I highly suspect the -vsync 0 to also work on the video, and I've had issues with that before. If I omit that, the video is fine, the TC is fine, but there is no metadata output, just the # timecode format v2

  


• Video converted using ffmpeg is blank after conversion

  28 août 2023, par Big boy

  I want to convert video types to MP4 and reduce their sizes (similar to WebP and other image formats).

  


  I downloaded a small sample from this site (the first one which is 1.5M).

  


  Then I used this command based on this answer :

  


  


  ffmpeg -i /Downloads/video.mp4 -c:v libx265 -vtag hvc1 -c:a copy /Downloads/video-result.mp4

  


  


  But after conversion, when I open it in the Google Chrome, it shows nothing. It's blank. While the original video works just fine.

  


  What do I miss here ?