[mythtv] [PATCH] MP3 options for TV recording

David Zanetti dave2 at wetstring.net
Sun Dec 7 00:39:04 EST 2003


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On Sun, 7 Dec 2003, Torbjörn Jansson wrote:

> I think this will cause problems with the directshow filters I did.
> Currently it uses some hardcoded defaults of 128Kbit and CBR, I haven't
> tried this patch so I don't know for sure.
> 
> Using directshow to convert a nuv file to avi (no recompression, direct
> streaming) will probably make the avi file contain invalid information about
> the mp3 stream. Maybe it will cause problems on normal playback too.
> 
> So I think that it might be nessesary to extend the nuv file format to
> contain atleast the bitrate and if its cbr/vbr/abr.

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?

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. 

But I'm no MPEG expert :)

(Happy to try out the directshow filter to see what it does..)

- -- 
David Zanetti           |  (__)             
#include <geek/unix.h>  |  ( oo    Mooooooo 
http://hairy.geek.nz/   |  /(_O ./         
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