FFmpeg imports mono tracks as stereo[SOLVED]

[marco.stanzani]

for saving space and *before* conversion to AAC by FFMPEG. very easy in principle, looking here http://wiki.audacityteam.org/wiki/Talk: ... ur_Project
still, if I save the mono track and re-open it I still se two channels. I cannot fine any oprion which sets the mono bit in the AAC file
If i do the same using the mp3 lame encoder I can see just one track in audacity when re-reading the saved fil
thanks for your help
I am 2.x and W7

[steve]

To convert a stereo track to mono in Audacity 2.x,
Select the track, then "Tracks menu > Stereo Track to Mono"
http://manual.audacityteam.org/o/man/tr ... eo_to_Mono

[DVDdoug]

...for saving space and *before* conversion to AAC by FFMPEG.

I wouldn't want a "fake" stereo file, but I don't think you'll save space by saving a mono file as mono AAC. AAC uses Joint Stereo by default, which encodes the L+R & L-R signals separately. With mono, there is no sound in the L-R "channel", and AAC (and MP3) are "smart enough" not to waste space when there is nothing to encode, so you are only encoding one channel's worth of information.

[Gale Andrews]

if I save the mono track and re-open it I still se two channels. I cannot fine any oprion which sets the mono bit in the AAC file
If i do the same using the mp3 lame encoder I can see just one track in audacity when re-reading the saved fil

Update to the currently recommended FFmpeg 0.6.2 ( http://manual.audacityteam.org/o/man/fa ... tml#ffdown ) then it will import mono AAC files as mono.


Gale

[marco.stanzani]

thanks, it works! and yes, saving mono files will save 50% of space approx (as expected)