FFAStrans forum

Posted: **Tue Jul 31, 2018 11:42 am**

Hello,

I am using below ffmpeg command to create mp4 files. we need constant 320kbps bitrate. most of case audio bitrate is variable.

Code: Select all

-c:v libx264 -s 1920x1080 -r 25 -aspect 16:9 -b:v 2000k -minrate 2000k -maxrate 2000k -bufsize 6000k -pix_fmt yuv420p -coder 1 -flags +loop -cmp chroma -partitions +parti8x8+parti4x4+partp8x8+partb8x8 -me_method 4 -subq 6 -me_range 16 -g 15 -keyint_min 1 -bf 0 -intra -refs 4 -sc_threshold 40 -i_qfactor 0.71 -b_strategy 1 -qcomp 0.6 -qmin 10 -qmax 51 -qdiff 4 -direct-pred 1 -fast-pskip 1 -vprofile high -vlevel 4.1 -movflags +faststart -b:a 320k -write_tmcd 0 -map 0:0 -map 0:1 -af "pan=stereo|c0=c6|c1=c7" -vf "drawtext=fontfile=/Windows/Fonts/arial.ttf:fontsize=60:x=800:y=900:box=1:boxcolor=black@0.5:rate='25000/1001':fontcolor=white:timecode='09\:59\:55\:00"

Posted: **Tue Jul 31, 2018 12:15 pm**

Although this has nothing to do with FFAStrans, specifying -b:a 320k should be sufficient. I don't know any other ways to "force" constant bitrate on compressed audio.

-steinar

Posted: **Tue Jul 31, 2018 12:43 pm**

I have kept 320kbps bitrate but it is showing variable and drop to 259kbps. i think need c:a libfdk_aac audio codec. I have kept my ffstrans and ffmpeg on storage location. could you please help me how can i compile c:a libfdk_aac.

Posted: **Tue Jul 31, 2018 8:28 pm**

Please stick to questions that is related to FFAStrans: viewtopic.php?f=5&t=235

Compiling ffmpeg with certain libraries is not for this forum and you will get much better guidance elsewhere.

-steinar

FFAStrans forum

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