What is the normal size of an audio file encoded to FLAC from a bluray...

[andyd2k]

I've been messing around with the settings in Ripbot and recently tried the xstream option - I expected the audio file size to be pretty large but it ended up being 1.5 gb for Road to Perdition.

Is that normal?

[tebasuna51]

The size of uncompressed audio WAV/PCM is

(Bitdepth/8) x (num_channels) x (samplerate) x (duration_in_seconds)

Compressed with FLAC you can obtain sizes around 50%

For Road to Perdition (117 m. = 7020 sec.)
Typical values: 16 bitdepth = 2 bytes, 5.1 channels and 48000 Hz
The uncompressed size can be 3.8 GB then the FLAC compression is around 40%

[ramicio]

Typical bit depth these days is 24 bits.

[tebasuna51]

Typical bit depth these days is 24 bits.

Are you suggesting than Flac compression is 26%?

[ramicio]

I usually see in the 40%s when I encode a stereo mix for a movie. That is 24/96. Why would the percentage change from a change in bit depth? I was just suggesting to use 24 in the formula to find the size because most lossless film tracks are 24 bits and not 16. A FLAC encoding from a DTS-HD or TrueHD should not be very far off in size from the original.

[tebasuna51]

There are also 24 bits artificially inflated from 16 bits, with 0's in less signifiants bits, and can be compressed like 16 bits.

Maybe I need change the word "Typical values" with "Probably values", but the user can know the source bitdepth easily.

[ramicio]

I could see that being very likely to be done in the music industry rather than the movie industry. Even so, utilities like eac3to will tell you if there are empty bits. I have even seen it warn me that some movie tracks are 20 or 18 bits. Weird.