I am trying to do some video conversion with FFmpeg. I have an mp4 video file (by which I mean, "it has an mp4 extension") that isn't being accepted by the Brasero disk burner, so I'm trying to use FFmpeg to convert it to a file that is actually mp4.

Here's what I'm trying:

ffmpeg -i 5.mp4 Parkford-05.mp4

It tells me that the AAC encoder is experimental and I should add -strict -2 to use it. So I try:

ffmpeg -i 5.mp4 Parkford-05.mp4 -strict -2

and get the same result.

How do I tell it to use the experimental encoder?

  • It is possible that you may not need to perform any re-encoding. Please show the complete console output of ffmpeg -i 5.mp4.
    – llogan
    May 21, 2015 at 5:17

1 Answer 1


Here is what you are looking for:

ffmpeg -i 5.mp4  -strict -2 Parkford-05.mp4


ffmpeg -i 5.mp4  -strict experimental Parkford-05.mp4




Additionally, if the file is named "5.mp4" but is not actually an mp4 file, the use of the mp4 extension in the name can cause problems. However, it is not always necessary to provide a file extension; having no file extension does not usually cause problems.

Try renaming the file "5" instead of "5.mp4" and see if that doesn't help.

  • Why do you answer with an avconv example? avconv != ffmpeg (although in this case it probably would not be too much different). Also, I'm guessing avconv will ignore -qscale if libx264 is being used as the encoder, or at least ffmpeg will; I'm not a user of avconv so you will have to check.
    – llogan
    May 21, 2015 at 5:22
  • @LordNeckbeard I have added the ffmpeg equivalent in case you absolutely need to or want to use ffmpeg or have maybe installed ffmpeg through some third party.
    – mchid
    May 21, 2015 at 16:42
  • The deprecated message refers to the fake, now dead "ffmpeg" from Libav, not ffmpeg from FFmpeg. Unfortunately the message did not make any distinction causing many users to assume it referred to ffmpeg from FFmpeg (some assume this was intentional). The package maintainer refused to clarify the message to be less confusing in that aspect although I requested a change, but this was unsurprising since he is also a Libav dev. FFmpeg returned to Ubuntu in 15.04.
    – llogan
    May 21, 2015 at 17:24
  • As for -qscale with no stream specifier, using it with a non-ancient ffmpeg build will result in various messages: Please use -q:a or -q:v, -qscale is ambiguous and [libx264] -qscale is ignored, -crf is recommended. For aac it is ignored as well. This can be confirmed by using the md5 muxer.
    – llogan
    May 21, 2015 at 17:32
  • @LordNeckbeard yeah i was referring to using qscale with avconv and assumed -q:a or q:v would be used with ffmpeg as stated in the link I provided trac.ffmpeg.org/wiki/Encode/AAC#NativeFFmpegAACencoder
    – mchid
    May 21, 2015 at 21:19

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