Quote:
Originally Posted by Momber
I just finished converting a True-HD track from HD DVD (Patch Adams) to lpcm and got this strange result:
Code:
[a04] Original audio track, L+R+C+LFE: constant bit depth of 16 bits.
[a04] Original audio track, SL+SR: constant bit depth of 24 bits.
How can a track have a bit depth of 16 and 24 bits at the same time? |
TrueHD always decodes to 24bit. A "16bit" TrueHD track also decodes to 24bit, but has the lower 8 bits zeroed out. So with this specific movie, obviously the surround channels have a true bitdepth of 24bit (all 24bits being made use of) while the other channels have the 8 lower bits zeroed out.
Quote:
Originally Posted by Momber
How should I treat the resulting lpcm track for further processing - as 16 or 24 bit?
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If you want to conserve the full quality you should treat it as 24bit track. E.g. FLAC compression will still work very well. The final FLAC filesize will be somewhere between a typical 16bit and a typical 24bit FLAC size.
Of course the surround channels are slightly less important than the left/center/right channels. So you could also say since the more important channels are only 16bit, anyway, you can use "-down16" to convert the whole track to 16bit. However, doing this will result in eac3to applying dither to the main channels, too, unfortunately. So I'd recommend to keep the track as 24bit.