Default ffmpeg codec when nothing is specified

ffmpeg codec
Sam picture Sam · Jul 22, 2013 · Viewed 13.2k times · Source

If I import a file to use with ffmpeg but dont specify anything about the codecs of any of the streams, will ffmpeg do anything? Is the default action to just copy the codecs? Or will ffmpeg encode the input file using some default codec?

Would the following two commands be the same? Or will the second re-encode and take ages?

ffmpeg -i input.mkv -c:v copy -c:a copy output.mp4

ffmpeg -i input.mkv output.mp4

Answer

llogan picture llogan · Jul 22, 2013

If I import a file to use with ffmpeg but dont specify anything about the codecs of any of the streams, will ffmpeg do anything?

ffmpeg will re-encode each stream in the input using default encoders. The encoders used will depend on how you configured ffmpeg. For example, if available libx264 will be the default encoder for mp4 output, but if not then mpeg4 will be used. By default ffmpeg will only re-encode one stream of each type and will ignore the rest (see stream selection).

Of your two commands the first one will use stream copy mode for the video and audio. Your second command will re-encode.

Related questions

ffmpeg convert mov file to mp4 for HTML5 video tag IE9

I looked everywhere here and on google - there is no valid command that works for IE9. some how IE9 is missing something. All that I tried worked everywhere else: chrome,safari,mobile device etc... I want one command that …

Read More
FFMpeg - How to copy codec ( video and audio ) from 'mp4' container to 'ts' container

i have this ffmpeg command ffmpeg -i c:\input.mp4 -vcodec copy -acodec copy -vbsf h264_mp4toannexb c:\output.ts. The above command successfully converts input.mp4 to output.ts. I need to implement the same functionality via code (…

Read More
What is video timescale, timebase, or timestamp in ffmpeg?

There does not seem to be any explanation online as to what these are. People talk about them a lot. I just want to know what they are and why they are significant. Using -video_track_timescale, how would I …

Read More