29

I am trying to determine video bitrate(For transcoding) using ffmpeg command,I tried following command.

ffmpeg -i 28572615.wmv

and it produces the following output

    Input #0, asf, from '28572615.wmv':
  Metadata:
    major_brand     : isom
    minor_version   : 1
    compatible_brands: isomavc1
    encoder         : Lavf57.36.100
  Duration: 00:02:50.92, start: 0.000000, bitrate: 1982 kb/s
    Stream #0:0: Video: wmv2 (WMV2 / 0x32564D57), yuv420p, 640x360, SAR 1:1 DAR 16:9, 25 fps, 25 tbr, 1k tbn, 1k tbc
    Stream #0:1: Audio: wmav2 (a[1][0][0] / 0x0161), 44100 Hz, 2 channels, fltp, 128 kb/s
At least one output file must be specified

If I use another video

ffmpeg -i with_out_sound.mp4

then i get the following output

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'with_out_sound.mp4':
  Metadata:
    major_brand     : dash
    minor_version   : 0
    compatible_brands: iso6avc1mp41
    creation_time   : 2015-04-21 05:14:57
  Duration: 00:00:27.86, start: 0.000000, bitrate: 500 kb/s
    Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 622x480 [SAR 1:1 DAR 311:240], 100 kb/s, 23.98 fps, 23.98 tbr, 90k tbn, 47.95 tbc (default)
    Metadata:
      creation_time   : 2015-04-21 05:14:57
      handler_name    : VideoHandler
At least one output file must be specified

The point I am confuse is that should I look in Duration metadata line or Video Stream metadata line(Stream #0:0) for video bitrate?

user2528012
  • 437

2 Answers2

28

The video bitrate is displayed in the video stream info. The format info contains the bitrate for all streams plus muxing overhead.

If the video bitrate is missing, then a dirty way to get that value is by subtracting the bitrate of all other streams from the total bitrate.

If that's not viable, run ffprobe to show packet sizes and add them together, show the stream duration and then calculate the bitrate by dividing the first number by the second.

$ ffprobe -v quiet -select_streams v -show_entries packet=size -of compact=p=0:nk=1 video.ext | awk '{s+=$1} END {print s}'
496797924
$ ffprobe -v quiet -select_streams v -show_entries stream=duration -of compact=p=0:nk=1 video.mp4  # format=duration if MKV
1501.761000
$ echo 496797924/1501.761000 | bc   # B/s
330810
$ echo '496797924/1501.761000/1024' | bc   # kB/s
323

Of course, this is only applicable if the video stream info does not sport a bitrate and estimating the bitrate by discounting the rate of all other streams is not possible either.

Cliff
  • 153
  • 7
Gyan
  • 38,955
8

Edit: See Cliff's note below if you have an MKV video instead of MP4.

The easiest way to get the bitrate of a video in proper format is to use FFMPEG's utility ffprobe

$ ffprobe -v quiet -select_streams v:0 -show_entries stream=bit_rate -of default=noprint_wrappers=1:nokey=1 inputvideo.mp4

This prints the raw bitrate value on its own so that you can easily use it in some kind of script.

Taken from here: https://write.corbpie.com/getting-video-bitrate-with-ffprobe/

rlittles
  • 208