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Gear / Technical Help => Playback Forum => Topic started by: Chilly Brioschi on July 24, 2009, 08:12:48 PM
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It seems that DVD Transports aren't able to output bit-transparent musical data.
http://www.benchmarkmedia.com/discuss/feedback/newsletter/2009/07/1/your-transport-giving-you-all-bits
Is Your Transport Giving You All The Bits?
Submitted by Benchmark on Mon, 2009-07-13 16:36
Issue:
2009-07
As a manufacturer of external digital-to-analog converters, Benchmark initiated a survey of DVD transports to determine which to recommend to their customers. The research was focused on bit-transparency – the ability to deliver the audio data on the disc to the digital output, bit-for-bit. Our research was performed with an Audio Precision SYS-2722 test station – a state-of-the-art analyzer for testing audio electronics.
Surprisingly, many DVD transports currently on the market fail to transmit the exact digital audio data bit-for-bit as it appears on the DVD. Of the DVD transports Benchmark has tested (8 as of this writing), all of them modified high-resolution audio data before sending it to the digital output (although they did pass 'Redbook', CD-quality 44-kHz, 16-bit data without modification). Let's examine what all of this means to your playback system.
Cause and Effect
Transports modify the high-resolution data in order to comply with digital copyright obligations to the publishers and distributors of music and video discs. The music and film industries are trying to prevent bit-for-bit copying of the recordings. Consequently, manufacturers of DVD transports have been forced to reduce the resolution of digital outputs to prevent digital duplication.
However, the sonic consequences of these modifications can be devastating to audio quality. We are able to measure sample rate, bit depth, and conversion quality with our Audio Precision test equipment. In almost all cases, the data modification includes poor quality sample-rate conversion (SRC) and word-length truncation. These processes defeat the benefits of high-sample-rate and/or high-bit-depth source material, and severely....
(continues at link above)
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Wow! Very interesting. Who would have thought there would be higher performance from a CD than from a high-resolution DVD??
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i wouldnt expect dvds to not upsample.
24-bit audio is still a finicky art, 10 years later