• Compression Techniques

  ffmpeg ignores my audio and video bitrate

  Posted by Tzvi Fleischman on August 31, 2014 at 9:12 am

  im running this command:

  -r 25 -i “import\\%%06d.tif” -i “import.mp3” -c:a aac -strict experimental -s:v 1280×720 -c:v libx264 -profile:v high -threads 16 -r 25 -pix_fmt yuv420p -b:a 320k -b:v 20000k “output.mp4”

  and the output audio bitrats is 288kbit/s and the output video bitrate is 855kbit/s.
  i checked those using mediainfo.

  can someone please help me to find a solution for that?

  thank you very much and have a great day!

  Jim Sustacek replied 11 years, 8 months ago 2 Members · 1 Reply
• 1 Reply

• 

  Jim Sustacek

  September 1, 2014 at 3:17 pm

  I think that video bitrate specification is just a rough target, and it can vary depending on what is needed for the source. To get it more precise, I think you can specify min and max bitrates and bufsize (sorry I don’t have the exact syntax handy,).

  Audio bitrate is usually more accurate — not sure what is happening there… I’d just try doing the audio part alone in its own mp4 file, testing different bitrate levels and options, and see if it is consistently off, or if it works correctly at, say, 128k.

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