2017-04-11, 06:44
(2017-04-10, 14:15)Soli Wrote: It's not my terminology. Feel free to send a mail to Dolby asking for clarification. DVD and Bluray players do a simple "downmix". LFE is *always* discarded in x.0 downmixes.
(2017-04-10, 23:16)Soli Wrote: which in turn will result in no LFE in not only 2.0 output, but any x.0 output.
Interesting statements..
This is what you can find in ATSC A/52, ETSI TS 102 366
Quote:Downmixing of the lfe channel is optional. An ideal downmix would have the lfe channel reproduce at an acoustic level of +10 dB with respect to the left and right channels. Since the inclusion of this channel is optional, any downmix coefficient may be used in practice. Care should be taken to assure that loudspeakers are not overdriven by the full scale low frequency content of the lfe channel.ATSC - page 92, ETSI - page 79
Quote:2.3.1.11 lfemixlevcod - LFE mix level code - 5 BitsATSC - page 163, ETSI - page 131
The lfemixlevcod 5 bit code specifies the level at which the LFE data is mixed into the Left and Right channels during downmixing. The LFE mix level (in dB) shall be derived from the LFE mix level code according to the following formula:
LFE mix level (dB) = 10 - LFE mix level code
As the valid values for the LFE mix level code are 0 to 31, the valid values for the LFE mix level are therefore +10 to -21 dB. For more information on LFE mixing, please refer to Section E3.9.
Quote:3.9 LFE downmixing decoder descriptionATSC - page 230, ETSI - page 176
For decoders with only 2-channel or mono outputs, where a dedicated LFE/Subwoofer output is not available, E-AC-3 enables the LFE channel audio to be mixed into the Left and Right channels at a level indicated by the LFE mix level code bit stream parameter. LFE downmixing occurs only if the LFE mix level code parameter is present in the bit stream and the decoder is operating in 1/0 (C only) or 2/0 (L/R) output modes with the LFE channel output disabled. For all other output modes, the LFE mixing information, if present, is ignored. Note that lfemixlevcode should be assumed to be 0 when it is not transmitted in the bit stream. For the 1/0 case, the decoder should perform a standard 2/0 downmix with the LFE mixed into the Left and Right channels, followed by a subsequent mix of the L/R channels to a mono C channel.