Master Quality Authenticated: Difference between revisions
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MQA is an audio recording, compression and distribution format created by Meridian Audio. |
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#REDIRECT [[Meridian Audio]] |
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The basic premise is, akin to XRCD/HDCD/aptX in some ways, to hierarchically compress the relatively little energy in the higher frequency bands into compressed data streams, which are then embedded into the lower frequency bands using proprietary dithering techniques. After a series of such manipulations, the downsampled 44KHz/16bit data (dithered partially with the last-step data stream), the layered data streams, and a final "touchup" stream (compressed difference between the lossy signal from unpacking all layers and the original) are provided to the playback device. |
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Given the low amount of energy expected in higher frequencies, and using only 1 extra frequency band layer (upper 44KHz band of 96/24 packed into dither of 48/16) and one touchup stream (compressed difference between original 96/24 and 48/16) are together distributed as a 48/24 stream, of which 48/16 bit-decimated part can be played by normal 48/16 playback equipment. |
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Compared to FLAC and other lossless formats, there is no factual bandwidth saving, and the 48/16 signal has easily-identifiable high-frequency noise in the 3 LSB bits. |
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Some early results from analysis of 2L-provided MQA files: http://www.computeraudiophile.com/blogs/miska/some-analysis-and-comparison-mqa-encoded-flac-vs-normal-optimized-hires-flac-674/ |
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Revision as of 07:19, 12 January 2016
MQA is an audio recording, compression and distribution format created by Meridian Audio. The basic premise is, akin to XRCD/HDCD/aptX in some ways, to hierarchically compress the relatively little energy in the higher frequency bands into compressed data streams, which are then embedded into the lower frequency bands using proprietary dithering techniques. After a series of such manipulations, the downsampled 44KHz/16bit data (dithered partially with the last-step data stream), the layered data streams, and a final "touchup" stream (compressed difference between the lossy signal from unpacking all layers and the original) are provided to the playback device. Given the low amount of energy expected in higher frequencies, and using only 1 extra frequency band layer (upper 44KHz band of 96/24 packed into dither of 48/16) and one touchup stream (compressed difference between original 96/24 and 48/16) are together distributed as a 48/24 stream, of which 48/16 bit-decimated part can be played by normal 48/16 playback equipment.
Compared to FLAC and other lossless formats, there is no factual bandwidth saving, and the 48/16 signal has easily-identifiable high-frequency noise in the 3 LSB bits.
Some early results from analysis of 2L-provided MQA files: http://www.computeraudiophile.com/blogs/miska/some-analysis-and-comparison-mqa-encoded-flac-vs-normal-optimized-hires-flac-674/