[FFmpeg-user] How can I convert mpeg2 5.1 audio to ac3?

Moritz Barsnick barsnick at gmx.net
Thu Nov 6 00:15:10 CET 2014

On Wed, Nov 05, 2014 at 23:01:57 +0000, Carl Eugen Hoyos wrote:
> el_processor.cpp is not license-compatible but 

Because it's GPLv2+, but libavfilter is LGPL? (Just checking, this
makes sense.

> indicates that it is possible to achieve what 
> is needed.

Reading the code may help to understand the original descriptions of
the methods needed to decode the 2-channel input (such as the article
and image I referred to, and possibly other whitepapers from Dolby
Labs), or find other references which mention Fourier transformation
for our digital domain. I didn't come up with that myself, but
should've. This could allow for a clean-room implementation. *shrug*

> PS: What did you google knowing that MythTV 
> does support PLII?

That's the part of the configuration _I_ didn't understand. I had only
jumped onto what you had concluded. ;-) I googled for surround
decoders, or dolby decoders, and omitting the MythTV fact didn't lead
me to MythTV.


More information about the ffmpeg-user mailing list