W dniu 2017-03-27 o 19:24, negin tebyani pisze:
and yes, I need to use constant bitrate. do I need to use 2 pass with constant bitrate?
You do not need second pass with constant bitrate, but with 2 pass - in first pass it log where it need bitrate and use that knowledge to distrubuate in second pass, because even with constant bitrate you have small variations along time. I add deblock filter before because reencoding favors block artifacts. From source info what you post i saw that you have the same resolutions, you do not need scale. So you doing 1280:720/50fps/yuv422p 4,4 Mbps -> 1280:720/50fps/yuv422p 2 Mbps ? I saw both samples and your was even more crispy sometimes, found that you doing 5 reframes, when others 6 (it help with bitrate a bit). So what you want improve? Dark parts? Or artifacts? Or fast motion scene blocks? Or more sharpen? Try that: ffmpeg -y -i in.mp4 -an -c:v libx264 -preset veryslow -b:v 2048k -bf 8**-qcomp 0.8 -pass 1 /dev/null ffmpeg -y -i in.mp4 -c:a aac -b:a 128k -c:v libx264 -preset veryslow -b:v 2048k -bf 8 -qcomp 0.8 -pass 2 out.mp4