Bitstream and lpcm help


New member
Username: Johnnp

Post Number: 2
Registered: Aug-08
bitsream and lpcm can anyone tell me the difference and what they mean cheers

Gold Member
Username: Frank_abela

Berkshire UK

Post Number: 3170
Registered: Sep-04

That's quite a tall ask I'm afraid! Put simply a bitstream is a 1-bit highly-oversampled (typically 256x or higher) signal.

LPCM is a multi-bit (16, 18, 20, 24 are the most common), not very highly-oversampled signal.

The main difference in the characteristics is that bitstream signals tend to give smooth results with no artefacts. LPCM signals tend to be more dynamic but suffer more easily from artefacts and 'ringing'.

Bitstream was originally developed to provide a cheaper D-to-A conversion process and to address some of the objections to LPCM playback's perceived harshness in the treble region. However, many people found that bitstream products tended to be too smooth and too lacking in dynamics.

DSD is the SACD format's recording standard and is a bitstream signal. DVD-A was designed with an LPCM standard. In practice, as a recording medium LPCM should offer better results thanks to wider dynamic range and less noise shaping requirements. Sony (inventors of SACD) argued differently. Both formats have failed, and there has been so little DVD-A released that true comparisons aren't really viable. That said, Blu-ray has a minimum LPCM standard which should give us better quality in theory.

I hope this answers your question, at least in part!
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