[FFmpeg-user] Predicting Transcoding Parameters

s00b4u 4u s00b4u at gmail.com
Sat Aug 20 06:08:27 EEST 2016


Hi,

I want to understand if there is any way to predict the transcoding
parameters values based on parameters of input and output file
specifications?
For example, my source file is MOV file. It's Video Bitrate is: 122113 KB/s
and Audio Bitrate is: 1536 KB/s.
I want to convert it into an MP4 file with Video Bitrate: 11 MB/s and Audio
Bitrate: 256 KB/s.

When I tried to do this transcoding, I used command:
ffmpeg -i myfile.mov -vcodec libx264 -acodec copy myfile.mp4
The results were way off the mark.

So, played around with values of crf and preset.
ffmpeg -i myfile.mov -vcodec libx264 -acodec copy -preset slow -crf 18
myfile.mp4
The results were better but still not as per requirement.
After multiple iterations (playing with different values of crf and
preset), I was able to find the right parameters.

My question: Is there a way to predict the transcoding parameters based on
input and output parameters of the video file? This can save time as we
don't have to do hit and trial.

Thanks.


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