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View Full Version : recommend me a codec and bitrate to encode dvd movie's ac3

Daedalus01
25th July 2007, 11:06
recommend me a codec and bitrate to encode dvd movie's ac3 (maintain 5.1), whilst retaining as much quality as possible (transparent).

i am considering AAC or vorbis, however i am unsure what is an optimal bitrate, and whether the rumours that vorbis cannot cope with 5.1 properly are true?
Guest
25th July 2007, 13:38
Leave it as the original AC3. Why do you want to change it?
nullstuff
25th July 2007, 13:41
...why not FLAC (http://flac.sourceforge.net/)?

-- nullstuff
Tack
25th July 2007, 14:01
Because my A/V receiver can't decode FLAC. :)
Daedalus01
25th July 2007, 14:44
Leave it as the original AC3. Why do you want to change it?

to save space

as for FLAC: interested, but automkv doesnt seem to support it. anyone know a program that can encode in x264 with flac?
buzzqw
25th July 2007, 15:12
flac ?

ehmm.. 10 seconds AC3 file 384kbs 5.1ch = 582Kb
the same file compressed with FLAC, compression 6 , STEREO =2.43 MB
the same file compressed with FLAC, compression 6 , 5.1CH =5.94 MB

BHH
nullstuff
25th July 2007, 16:01
...oops! I always backup my DVD in x264 lossless with FLAC audio! :D ...backin' serious: I guess LC-AAC@256 would be a good point.

-- nullstuff
Daedalus01
26th July 2007, 02:58
flac ?

ehmm.. 10 seconds AC3 file 384kbs 5.1ch = 582Kb
the same file compressed with FLAC, compression 6 , STEREO =2.43 MB
the same file compressed with FLAC, compression 6 , 5.1CH =5.94 MB

BHH

could you please explain this? why does filesize increase with FLAC? also what automated encoding program supports x264 and FLAC?
mitsubishi
26th July 2007, 03:08
could you please explain this? why does filesize increase with FLAC?
Because FLAC is lossless. So it is an exact representation of the output of the AC3 decoder. Clearly this is not a sensible thing to do, since the AC3 decoder is quite capable of outputting it's output itself.

But if you have an uncompressed digital source, such as an audio CD, then you can use FLAC to compress it, then when you decode the FLAC, you get the exact contents of the CD. If you compress the CD with lossly compression then the output of that decoder is not the same as the original CD, but an imperfect representation.