Re: Could someone lend me a few instructions for Mencoder and CLi encoding with ffmpe
Well the following is a pretty solid encoding string for FFmpeg and should furnish and excellent starting point for further usage of this amazing application:
Code:
ffmpeg -i input \
-acodec libfaac -aq 100 \
-vcodec libx264 -preset slow -crf 22 \
-threads 0 output.mp4
In the interest of clarity I will keep the explanation pretty basic, there is a great deal more involved and extra choices that can be made but the very basics are:
- ffmpeg -i input: The -i option simply tells FFmpeg what the input file is.
- -acodec libfaac: The -acodec option selects the audio codec for the sound conversion and in this case aac sound has been selected using the external faac application. (Libraries external to FFmpeg always are named with a 'lib' prefix).
- -aq 100: The -aq option selects the quality of the sound, some use -ab to manually specify the bitrate, something like -ab 128k would then be used.
- -vcodec libx264: The -vcodec option selects the video codec to be used for the conversion. x264 encoding is pretty much the best encoding to use at the moment and again you see the 'lib' prefix indicating that you are not using an encoder 'native' to FFmpeg.
- -preset slow: The encoder comes with a bewildering number of options but there are several lists of options that can be selected, as has been done here, with the -preset option.
- -crf 22: This option selects the quality of the output video and indicates 'Constant Rate Factor', 22 is a reasonable number to start with.
- -threads 0: The -threads option allows a single FFmpeg process to have multiple levels of activity with this single process. This will enable your encoding job to run faster. The '0' value allows x264 to decide how many threads it can safely use rather than you selecting a value.
- output.mp4: This specifies the out file name and creates an mp4 container, another safe option here would be 'output.mkv'.
Hopefully this makes things a little clearer?
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