[mythtv] [PATCH] MP3 options for TV recording

Derek Atkins warlord at MIT.EDU
Mon Dec 8 09:53:13 EST 2003

David Zanetti <dave2 at wetstring.net> writes:

> Hmm, every MPEG audio frame has (at least) the bitrate for that frame in
> the frame header, so presumably the decoder should base it's decoding off
> that.. What is being hardcoded?

Indeed, the audio decode in avformatdecoder.cpp DOES base the audio on
the data in the header...  HOWEVER, it requires three consecutive
audio packets with the same (new) audio information to change the
audio parameters.

> It shouldn't matter to the decode side at all what options it was encoded
> with, it should just take each frame and handle whatever bitrate it
> sees. So I'm not sure I see the value to add cbr/vbr/abr, since the only
> difference on the decode side is potentially different bitrates for each
> frame. 

This is correct.


       Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
       Member, MIT Student Information Processing Board  (SIPB)
       URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
       warlord at MIT.EDU                        PGP key available

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