In ffmpegx, there's an option for "High Quality". How can I obtain the same effect by using the command line tool ffmpeg?
More generally, is it possible to check which ffmpeg options are used behind the scenes by the ffmpegx GUI?
asked Jul 25, 2011 at 17:24
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1 Answer
How to find out the command line used by ffmpegX?
If you encode a video, you will see the command line used in the Process Information window.
Just click the blue i button next to the encoding process and you will find the command line in the top field starting with printf .... Copy it to some text editor to inspect the whole command.
This would reveal something like:
printf "Encoding started on " && date && /Applications/ffmpegX.app//Contents/Resources/ffmpeg -i /Users/werner/Desktop/echo-tv/01_BAD_talking_head.avi.MP4 -y -threads 2 -map 0.0:0.0 -f avi -vcodec xvid -b 733 -aspect 16:9 -s 480x272 -r pal -g 240 -me epzs -qmin 2 -qmax 9 -acodec mp3 -ab 128 -ar 48000 -ac 2 -map 0.1:0.1 -benchmark /Users/werner/Desktop/echo-tv/01_BAD_talking_head.avi.MP4.ff.avi && printf "Encoding completed on " && date && printf "\a"
That's the whole ffmpeg command used.
How to obtain the "High Quality" setting in ffmpeg?
In the particular case of the "High quality" setting, I unfortunately could not find a difference between the command line used with "High Quality" and without "High Quality" enabled. I tested this by encoding a video using ffmpeg and XviD. According to the ffmpegX manual, the "High Quality" setting ...
[...] encodes each macroblock in all modes and then choose the best. Slower, but results in better quality and file size.
It should be the same for ffmpeg and mencoder, as they both use libavcodec to convert. Maybe I couldn't see a difference in the command line because of the video I tested this with.
My guess is that it's the -mbd option used for macroblock decision or the -4mv option for four motion vectors per macroblock (MPEG-4 only). There are no other options related to macroblocks in ffmpeg.
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thanks for this. I know I can get more information by clicking on the "i" symbol. Still that doesn't give the "exact" ffmpeg command which is used. For example, in the above screen, I would have loved to see the -s option for the frame_size or the other ffmpeg options used to get that specific bitrate. Did it set the -minrate and -maxrate to 246? Is it using a variable bit rate? And so on... Jul 26, 2011 at 5:49
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Roberto, take a closer look at the top field, not the big one below! I'll edit the question to make it more clear. This is the ffmpeg command used, there's nothing more. Maybe you can show a more concrete example in your question if there's another problem.– slhckJul 26, 2011 at 8:32
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Ah! Sorry about that, I completely missed the top field and was focusing on the main window... Jul 26, 2011 at 8:52