The default DropBox shared link have the following structure: Sometimes you just want to extract a minute (or less) from a 2 hours (or maybe more) video file, which is stored on a DropBox directory.Ĭhances are that you will be able to download the entire file with a DropBox “Shared Link”.īut if you want to download just a portion of that file, without downloading the entire file, you can easily do so by changing the query parameter of your DropBox shared link. The final working command will be as in this example: ffmpeg -i YOUR-AUDIO.aac -i YOUR-PICTURE.jpg -vf 'pad=ceil(iw/2)*2:ceil(ih/2)*2' -crf 18 -map 0:a -map 1:v -r 25 YOUR-FINAL-VIDEO.mp4Įxtracting Portion of a Video or Audio from a Shared Dropbox Link Then specify an output quality for the h264 encoder, with the “-crf” option ( default value is 23), and finally mapping your audio and picture inputs with the “-map” option.

Then, again, you may want to specify the rate (FPS=frame per second) of the video input with the “-r” option (after the “-i”).

(See FFMPEG’s Color Syntax reference for more details on changing color values). The above command uses the FFMPEG’s “ Pad Filter“, which divides both the original widht and height by 2, round it up to the nearest pixel ( ceil), multiply by 2 again for make it an even number and adding black padding pixels (if needed) up to this number.Ĭolor of the padding can be changed using the option “:color ” at the end, such as follows: Thus, in order to produce a standard h264 file with audio and 1 picture, you may want to include the following filter into your instructions: -vf 'pad=ceil(iw/2)*2:ceil(ih/2)*2' This is beacause the h264 encoder needs even dimensions.

Error initializing output stream 0:1 - Error while opening encoder for output stream #0:1 – maybe incorrect parameters such as bit_rate, rate, width or height” “ width ( or height) non divisible by 2 ( w x h). You could instruct FFMPEG to do the following: ffmpeg -i YOUR-AUDIO.aac -i YOUR-PICTURE.jpg -map 0:a -map 1:v output.mp4īut with the above instructions, you may encounter the following error: You may want to add an audio track onto a single picture so to create an h264 file, using the audio lenght as the total lenght.

Ffmpeg mac downloda