At what bitrate does AC3 5.1 becomes transparent?

[ProVision]

Hi,

As you have read in the title, I am asking as at what exact bitrate at 4800KHz 6 channel (5.1) does AC3 ACM and the built-in AC3 in AVIDemux become Virtually transparent.

I don't need it to be 100% transparent Lossless quality, as I am just transcoding DTS to AC3 because a program of mine which doesn't support DTS ATM that will then encode it to NeroAAC at q0.27, q0.29 or q0.31 still haven't decided. I prefer having AC3 anyway because DTS takes up waay too much space and I can't afford any more storage at the moment.

Thanks in advance!

[Guest]

"Virtually transparent" is highly nebulous. Just pick a bitrate that sounds transparent to you.

[Sparktank]

Depending on the movie, I sometimes hear no difference between 448 and 640.

Is your program transcoding (DTS to AAC) or is it going to transcode the (AC3 to AAC ---> DTS to AC3 to AAC)?
That part's a little unclear.

For general movie playback, I have no problems using AAC over AC3.

If you want to save space and preserve quality, AAC is a fine and dandy choice.
NeroAAC and QAAC (http://www.videohelp.com/tools/qaac) both produce good quality.

[SeeMoreDigital]

...I am just transcoding DTS to AC3 because a program of mine which doesn't support DTS ATM that will then encode it to NeroAAC at q0.27, q0.29 or q0.31 still haven't decided.
If you're interested... LoRd_MuldeR's LameXP (http://forum.doom9.org/showthread.php?t=157726) can encode DTS to AAC ;)

[ProVision]

@Sparktank
Software #1 Option #1: Copy Video, convert DTS to AC3 Aften (Max 384kbps)
Software #1 Option #2: Copy Video, convert DTS to ACM AC3 (Max 640kbps) (Much slower than Option #1)

Software #2: Encode video, encode audio to NeroAAC q0.26

P.S. What is your audio device?

@SeeMoreDigital Thanks, that's a very attractive option. If I feed it a dual audio video file... What will happen? Will it detect one? Both? Or nothing? Anyways, it's not a biggie, as demuxing nowadays can't be easier! Thanks!!

[Sparktank]

@Sparktank
P.S. What is your audio device?

BD player (with file support) to Kenwood surround sound receiver.
DVD's I encode from my BD's are @448.
Rarely, I'll rip a movie to a smaller file, but if I did, it's either AC3@640 or AAC with insane settings (QAAC: -V127 -q 2).

Or the laptop, in which case I'll probably just watch a remux with original audio connected to Kenwood receiver.

But most times, it'll just be from laptop to TV (via HDMI) with original audio from a remux.

Having a 4TB external comes in handy for remuxes option. :devil:

[ProVision]

LOL yeah. Me stuck with 1.5TB can't afford much.

[mindbomb]

thres a thread about this at hydrogenaudio. iirc, the gist was that the official dolby digital encoder didnt do a good job with test files.

[ProVision]

Wow! That must be a hit to their reputation huh?