[FFmpeg-user] mov [ProRes/pcm_s24le] -> mp4 same quality

Carl Eugen Hoyos cehoyos at ag.or.at
Fri Nov 18 21:49:20 CET 2011

HallMarc Websites <marc <at> hallmarcwebsites.com> writes:

> AAC is not limited to -strict experimental because of any quality issue. My
> experience has shown that AAC produced a much better quality audio than
> libfaac.

Since other people are reading this list:
The native FFmpeg AAC encoder can only be used with -strict experimental because
it has significantly worse quality than all external AAC encoders (libfaac is
not the only one), meaning audio quality is worse for a given bitrate.

I usually test the native FFmpeg AAC encoder with slightly increased bitrates
(>64k), it is absolutely usable imo, dts for example is definitely not usable
(to name another audio encoder that needs -strict experimental).
But there are many reports and requests both on this list and the developer
mailing list about the relatively poor quality of the native AAC encoder
compared with other AAC encoders.


> I see some postings, maybe someone here that KNOWS can expound on it, that
> say libfaac/faac were removed from ffmpeg builds due to licensing issues.

You cannot fulfill the requirements of the GPL for libfaac, meaning you cannot
legally distribute a binary of FFmpeg linked against both libfaac and a GPL'd
library, for example x264.

> I've asked you once before and now I plead with you, stop posting garbage in
> this list. You are not helping anyone by misinforming them.


Carl Eugen

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