[SOLVED] How can I use regex to extract video bitrate

L4Z3R · 05-12-2018, 06:20 PM

Hi folks,

I am trying to get the bitrate of a video to use in a variable. This is the best I can do with my limited knowledge of regex.

Code:

 x=$(ffmpeg -i  lt.mp4 2>&1| grep DAR | awk -F, '{print $5 }' | grep -P "\d" | awk '{print $1 }')
% echo $x
1261

Is there a better or cleaner way to do this? Thanks

L4Z3R · 05-12-2018, 06:34 PM

I tried another command. So far, this is the cleaner way

Code:

vb=$(mplayer -identify -vo dummy -ao dummy lt.mp4 2>/dev/null| grep "VIDEO:" | awk '{print $7 }')
echo $vb
1261.8

If you guys know a better way or command. I would appreciate it. Thanks

syg00 · 05-12-2018, 07:02 PM

awk has all you need - you should never need to pipe grep or similar to it.

Code:

awk '/VIDEO:/ {print $7 }'

L4Z3R · 05-12-2018, 07:15 PM

Quote:

Originally Posted by syg00

awk has all you need - you should never need to pipe grep or similar to it.

Code:

awk '/VIDEO:/ {print $7 }'

That's awesome syg00, thanks

+1

Sefyir · 05-12-2018, 09:12 PM

Assuming the file actually reports the bit rate for video.
What happens when it doesn't report it, but reports the total bitrate?

Code:

  Duration: 00:00:57.83, start: 1.400000, bitrate: 571 kb/s
  Program 1 
    Metadata:
      service_name    : Service01
      service_provider: FFmpeg
    Stream #0:0[0x100]: Video: h264 (Constrained Baseline) ([27][0][0][0] / 0x001B), yuv420p, 412x320 [SAR 7520:7519 DAR 94:73], 30 fps, 30 tbr, 90k tbn, 60 tbc

If you know what you're working with, syg00's answer will be fine, but if you're working with a variety of unknown files you may need to look at edge cases, figuring out the video bit-rate by deducting audio bitrate etc.

Reference
https://superuser.com/questions/1106...e-using-ffmpeg

syg00 · 05-12-2018, 09:41 PM

Too true - but life would be pretty bland without edge cases ....

L4Z3R · 05-12-2018, 10:10 PM

Quote:

Originally Posted by Sefyir

Assuming the file actually reports the bit rate for video.
What happens when it doesn't report it, but reports the total bitrate?

Code:

  Duration: 00:00:57.83, start: 1.400000, bitrate: 571 kb/s
  Program 1 
    Metadata:
      service_name    : Service01
      service_provider: FFmpeg
    Stream #0:0[0x100]: Video: h264 (Constrained Baseline) ([27][0][0][0] / 0x001B), yuv420p, 412x320 [SAR 7520:7519 DAR 94:73], 30 fps, 30 tbr, 90k tbn, 60 tbc

If you know what you're working with, syg00's answer will be fine, but if you're working with a variety of unknown files you may need to look at edge cases, figuring out the video bit-rate by deducting audio bitrate etc.

Reference
https://superuser.com/questions/1106...e-using-ffmpeg

If this is the case, then I would just use some arbitrary value between 2K to 5k to encode a video. These bitrates would yield good video quality depending on the resolution of the video.