I think you mean to say Eight (7.1) analogue outputs on BDP....... Any idea why HD audio viz MLP/ DSD on DVD-A/ SACD are only 5.1?
No, I meant 7.0. The sub output is standard across all Codecs - whether 5.1, 6.1 or 7.1. If you talk about number of channels, then you say 6, 7, or 8 channels which included the LFE output. In AVRs that have analogue ins, in addition to the LFE/Sub in, you will have 5, 6 or 7 RCA connectors.
hey venkat are film soundtracks being recorded on 7.1 these days?
Dolby TrueHd and DTS-HD follow different paths.
Dolby TrueHD bitstream can carry upto 14 discreet channels. For Blu-Ray, TrueHD is actually an optional code which could be 8 discrete audio channels at 96 kHz or 2 channels at 192 kHz. By default, all Blu-Ray carry standard AC3 audio track which is the primary audio. When it recognises a hardware that can decode the additional tracks, they are added to the primary audio track. Thus all TrueHD players can down mix to upto 2 channels.
DTS-HD also contains the original audio stream, but has a 'difference' or 'residual' stream. that contains the variation between the original movie sound and the lossy DTS compression. During recording, the signal is sent as two streams to the encoder. The first is sent to the primary or core encoder for compatibility with standard DTS encoding. In the player, a decoder decodes this signal as is done in a DVD. The second stream compares the differences between the decoded signal to the original audio and generates the additional audio signals that are needed. This is encoded by a lossless encoder and packed with the primary audio signal. The process is reversed during decoding. Because DTS works on the concept of calculating differences between original sound track and the DTS lossy compression, it uses variable bit rates as compared to Dolby TrueHD.
Though early Blu-Ray discs contained only the primary audio track, new discs contain full 8 channels to represent what the original film has.
Cheers