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zzvelik
2009-12-09, 07:54
I read a post at the AVS forum and it doesn't look like we'll ever have 24/96 on the SB3 due to the CPU according to Michael (See below). The post was made almost 2 years ago, so if the CPU is still regarded as the bottleneck esepecially since I have a modded SB3 by Bolder Cable and was hoping to keep it vs upgrading to another unit.

<<The Transporter also has the ability to play 24/96 files (and 24/88 in beta firmware) while the Squeezeboxes tops out at 24/48 (because we're maxing out the SB's CPU) even with an outboard DAC.

Mike
__________________
Michael Valera
Online Communities Manager
slimdevices.com>>

http://www.avsforum.com/avs-vb/showthread.php?t=991049

radish
2009-12-09, 16:48
No.

iPhone
2009-12-10, 10:44
I read a post at the AVS forum and it doesn't look like we'll ever have 24/96 on the SB3 due to the CPU according to Michael (See below). The post was made almost 2 years ago, so if the CPU is still regarded as the bottleneck esepecially since I have a modded SB3 by Bolder Cable and was hoping to keep it vs upgrading to another unit.

<<The Transporter also has the ability to play 24/96 files (and 24/88 in beta firmware) while the Squeezeboxes tops out at 24/48 (because we're maxing out the SB's CPU) even with an outboard DAC.

Mike
__________________
Michael Valera
Online Communities Manager
slimdevices.com>>

http://www.avsforum.com/avs-vb/showthread.php?t=991049

Not possible for Receiver or SB3 Classic to do 24/96 native. If one has enough processing power on ones server and at least SC 7.3.1 the Server can use SoX to down convert the files enabling them to be played at 24/48 so that one doesn't have to have separate files.

zzvelik
2009-12-13, 20:52
I had downloaded a sample of Mozart's Violin Concerto No. 4 in D Major KV 218 Allegro in the 24BIT/96kHz FLAC format a few months ago and had totally forgotten about how good it sounded. For reference, the site where I downloaded is: www.2l.no/hires/index.htm

That site's server isn't up at the moment, here's the cache version:
http://74.125.155.132/search?q=cache:Wky_snLrI1MJ:www.2l.no/hires/index.html+mozart's+Violin+Concerto+No.+4+in+D+Maj or+KV+218+Allegro+24/96&cd=2&hl=en&ct=clnk&gl=us

I replayed it a few minutes ago on the latest firmware and here's what it says under "more info":

Bitrate: 2593kbps VRB (Converted to 705.6kbps ABR).

So, does this mean that the SB3 actually supports 24BIT/96kHz format to a degree, but has to compress the bitrate? Just asking since I'm not sure how the Touch will compare in overall sound quality vs a digitally modded SB3 with an upgraded power supply.

snarlydwarf
2009-12-13, 21:58
Bitrate: 2593kbps VRB (Converted to 705.6kbps ABR).

So, does this mean that the SB3 actually supports 24BIT/96kHz format to a degree, but has to compress the bitrate? Just asking since I'm not sure how the Touch will compare in overall sound quality vs a digitally modded SB3 with an upgraded power supply.

No, the server uses SoX to resample it.

pfarrell
2009-12-13, 22:09
snarlydwarf wrote:
> zzvelik;495418 Wrote:
>> Bitrate: 2593kbps VRB (Converted to 705.6kbps ABR).
>>
>> So, does this mean that the SB3 actually supports 24BIT/96kHz format to
>> a degree, but has to compress the bitrate? Just asking since I'm not
>> sure how the Touch will compare in overall sound quality vs a digitally
>> modded SB3 with an upgraded power supply.
>
> No, the server uses SoX to resample it.

More specifically, note that seanadam's prior posting noted that:
"FLAC typically uses about 750 kbps (or 0.75 Mbps) bandwidth"

so @zzvelik's 705kbps is typical for FLAC of redbook audio.
The server is converting the stream to normal flac. The SB3 does not
support high/wide bit rates.

The Touch will. Another reason that the Touch is better than the
SB3/Classic.

And to the point of the subject topic of this thread. The SB3/Classic is
done. Its never going to do anything more than it does today. The Server
may do fancy stuff in the future, but its not going to be enhanced. The
future is the Touch.


--
Pat Farrell
http://www.pfarrell.com/

Mnyb
2009-12-13, 22:35
I think sox actually makes 24/48 of it this 705kbps is a somewhat bogus number, the players reports on converted bitrates is not to be trusted.
it's similar to other transcoding, but there this number often are a better guess

However the conversion is running perfectly I *think* it is just this info that often is a bad gues not more, the number should be higher for 24bit files .

They should prepare another bogus number for 24bit files around 1400 something, but it's not a high priority I imagine .

If SOX would make 16/48 out of 24/96 instead of 24/48 I'm sure one of those paranoid audiophiles would have cried foul in the audiphile section ;)

pfarrell
2009-12-13, 22:52
Mnyb wrote:
> If SOX would make 16/48 out of 24/96 instead of 24/48 I'm sure one of
> those paranoid audiophiles would have cried foul in the audiphile
> section ;)

Making 16/48 out of 24/96 is trivial, any embedded processor can do
that, just throw away every other sample, and truncate them all to 16
bits using a shift-right by eight instruction.

Converting 24/96 to 16/44.1 or even 24/44.1 is a different matter
completely. Doing it "right" is not just simple division.

--
Pat Farrell
http://www.pfarrell.com/

Mnyb
2009-12-13, 23:12
Mnyb wrote:
> If SOX would make 16/48 out of 24/96 instead of 24/48 I'm sure one of
> those paranoid audiophiles would have cried foul in the audiphile
> section ;)

Making 16/48 out of 24/96 is trivial, any embedded processor can do
that, just throw away every other sample, and truncate them all to 16
bits using a shift-right by eight instruction.

Converting 24/96 to 16/44.1 or even 24/44.1 is a different matter
completely. Doing it "right" is not just simple division.

--
Pat Farrell
http://www.pfarrell.com/

But it is doing 24/48 right ?

btw should you not use dithering of some kind when going 24>16 ? truncation is simple but i think they use more finesse these days .

And SOX is not just throwing away every other sample either, that was what the SB3 did internally that would get you aliasing problems ? and other problems to ?
some filtering must be done to ensure no content above 1/2 the target sample rate exist when lowering the sample rate .
I have no clue to what sox sample rate conversion algorithm is btw, but I'm sure it is a lot more than throwing 1/2 of the samples away otherwise it would not use 70% of my cpu on my 1,2gHz server ,. So it must employ some kind of digital filter to I think .

pfarrell
2009-12-13, 23:21
Mnyb wrote:
> But it is doing 24/48 right ?

I have no idea. I've never looked at Sox

> btw should you not use dithering of some kind when going 24>16 ?
> truncation is simple but i think they use more finesse these days .

If you care about sound quality, you should always use a dithering
algorithm when truncating. Its trivial as well, just add an eight bit
random number to the 24 bit value, and then shift right.

There are better algorithms, but in an embedded system, adding is nearly
as trivial as shifting.

Again, I don't know what Sox is doing. Proper conversion from 96 to 44.1
is more complex, but there is a chance that the Classic/SB3 can process
48kHz natively. So there is no need to bother going to 44.1

Obviously if you are doing FFTs to try to use digital transformation,
then you will use a ton of CPU power

--
Pat Farrell
http://www.pfarrell.com/

Mnyb
2009-12-13, 23:46
This is why they don't do in the "embedded system" aka SB3 anymore .
But since 7.3 something uses SOX

SB3 supports 24bit 48kHz , I tried my 24/48 files, they do not launch the flac and sox processes in the server.

Off topic : the "light" version of the squeezeboxserver would not have sox so the Squeezebox Touch would not do transcoding for older connected players.
The Touch itself would not need it as it does 24/96 .

I like that approach better, as 24/96 is getting somewhat more common, there could be cases where family members would listen to different 24/96 files at the same time , my rather lightweight server can not run more than one transcoding process at the time . I'm speculating that 3 or 4 parallel transcoding processes would give even a modern 4gHz quad core a headache.
So 24/96 in a cheaper players than transporter is good even not considering sound quality.

Syncing is no problem sbs is smart enough to use the same stream so server load is decent even syncing 3 players to a 24/96 album

cliveb
2009-12-14, 01:01
Making 16/48 out of 24/96 is trivial, any embedded processor can do that, just throw away every other sample, and truncate them all to 16 bits using a shift-right by eight instruction.
I see you've already responded to the issue that dither should be added when truncating.

There's another issue that makes 24/96 -> 16/48 difficult for an embedded processor (far more difficult than the dithering requirement). You need to lowpass filter the signal before resampling, and that requires more CPU power than a typical embedded system can provide. You can't just throw away every other sample - if the 96kHz data has anything above 24kHz, you'll get aliasing.

The SB3 used to do exactly this - throw away every other sample. It got away with it because the overwhelming majority of 96kHz audio files contain little if anything above 24kHz anyway, so the aliasing artefacts were at a very low level. In the context of SqueezeCenter running on a low power CPU (eg. a NAS), I think it was a sensible pragmatic compromise. At some point Sean seems to have decided it wasn't acceptable, and later SB3 firmwares removed the capability, relying instead on SOX on the server.

cliveb
2009-12-14, 01:14
Off topic : the "light" version of the squeezeboxserver would not have sox so the Squeezebox Touch would not do transcoding for older connected players. The Touch itself would not need it as it does 24/96.
So what will the Touch do with a 24/192 stream? It doesn't have the horsepower to downsample. And as you say, what about playing 24/96 on an SB3 from SqueezeboxServer Light running on a Touch, which can't run SOX?

Lots of non-geek users are going to run a Touch with SBS-Lite. They are clearly a major slice of who the new products are aimed at. And they might well buy some 24/96 stuff online. So when they connect up that used SB3 they got as a bargain on eBay and their 96kHz files fail to play, they're going to be confused/miffed. Don't expect them to do the necessary research to find out they need to perform a one-off downsample to 48kHz using a separate PC.

I predict that the only practical solution to this issue is the reintroduction of the "drop every other sample" firmware kludge - not only on the SB3, but also on the Touch for 192kHz material.

Mnyb
2009-12-14, 02:05
So what will the Touch do with a 24/192 stream? It doesn't have the horsepower to downsample. And as you say, what about playing 24/96 on an SB3 from SqueezeboxServer Light running on a Touch, which can't run SOX?

Lots of non-geek users are going to run a Touch with SBS-Lite. They are clearly a major slice of who the new products are aimed at. And they might well buy some 24/96 stuff online. So when they connect up that used SB3 they got as a bargain on eBay and their 96kHz files fail to play, they're going to be confused/miffed. Don't expect them to do the necessary research to find out they need to perform a one-off downsample to 48kHz using a separate PC.

I predict that the only practical solution to this issue is the reintroduction of the "drop every other sample" firmware kludge - not only on the SB3, but also on the Touch for 192kHz material.

Or run a real server , but it would be interesting see what happens if you got an SB3 and one touch and sync them with an 192kHz files as a source.

This is academic anyway there is not much music available anyway on 24/96 and 90% of it is "audiophile music" that that no sane person would choose anyway. Anyone with a music interest would sure choose a better performance of the same music with real musicians .

So it's is much more likely that a squeezebox owner would stumble over one of the other 1000 open bugs before this one.

The no transcoding issue has far greater implications than hirez files for example an SB3 don't do AAC or ALAC the Touch is slated to do that natively.
There are many non native formats what about VMA lossles .
The AAC or lowbitrate ogg issue could hamper some web radio .

The tiny-SC server has limit, so a full blown server is needed in some cases.
I personally think that the lack of web-UI on tiny-SC will fill this forum with whining ;)