> -----Original Message----- > From: ffmpeg-user [mailto:[email protected]] On Behalf Of > s00b4u 4u > Sent: 20 August 2016 06:08 > To: FFmpeg user questions > Subject: [FFmpeg-user] Predicting Transcoding Parameters > > 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.
There are many parameters and most are interdependent. To "predict" some you may need to specify many. E.g. h264levl.bat at this link (https://www.dropbox.com/s/notf94wyt1r0rmk/H264_level_and_maxref.rar?dl=0): "for given encoding parameters, calculate H.264 level, maxDPB and maximum x264 --ref". It may be of use, if only to illustrate the difficulty of the problem ;-). > Thanks. > _______________________________________________ > ffmpeg-user mailing list > [email protected] > http://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email [email protected] > with subject "unsubscribe". _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
