In Reply to: RE: Using JRiver 19 to convert standard 44.1/16 wav to DSD posted by Ed Hsu on July 24, 2014 at 22:34:14:
Thanks for the link. I'd missed this thread. I can confirm that HQPlayer requires careful selection of filters and other configuration settings to get good results.
One thing that I didn't understand was the comment that the lack of an idle core might lead to a timing error on a USB packet, implying that these go out every millisecond under software control. Is this correct? It seems more likely that the 1 msec isochronous packets are timed by the USB controller hardware which at least double buffers. Therefore if the CPU were less than 1 msec late the next packet would still go out on time. (It could be that it doesn't work that way with some drivers, if so I would consider that a bug.) In the case of the USBPAL driver for Windows that came with my Mytek if the processor can't keep up then then the error counters will increment. Usually I can hear a glitch anytime this happens, something that seldom happens when I am just listening to music, but happens frequently when using HQPlayer with room correction if I attempt to surf the web, etc... It is possible to reduce the frequency of this happening by increasing the number of these 1 msec buffers using the USBPAL control panel. The choices are 1, 2, 4, 8, 12, 16 msec. As expected, I found that lower numbers produced more frequent glitches but better sound quality between glitches, also the glitches were usually harder to hear when they happened.
I do not like the idea of trying to tune a system where there is no access to the necessary documentation, e.g. logic diagrams for the USB hardware and source code for the driver. With this information most questions about how the system really works could be immediately answered, rather than relying on guess work and speculation.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- RE: Using JRiver 19 to convert standard 44.1/16 wav to DSD - Tony Lauck 07/25/1407:32:39 07/25/14 (2)
- RE: Using JRiver 19 to convert standard 44.1/16 wav to DSD - Ed Hsu 22:27:56 07/26/14 (1)
- RE: Using JRiver 19 to convert standard 44.1/16 wav to DSD - Tony Lauck 07:20:15 07/27/14 (0)