Compression level

[Covenant]

I am just ripping The Sky Moves Sideways to my computer at compression level 4 on dB Poweramp. Whats the best compression level?

[Ali Tait]

If you are talking about FLAC, it shouldn't make a difference. Default level is usually 5.

[Stratmangler]

Use 5 maximum.
You don't get any better quality at 8, just more compression, which then takes more processing to decompress at playback.
Squeezeboxes are generally fine at 5.

[Rothchild]

Actually, as I understand it, the data compression on FLAC is 'front-loaded'. So playback processing levels are roughly the same regardless of the encoding level, more processing is used to encode at the higher compression levels. Given that processing is so cheap nowadays there's not really any reason I can see not to do everything at level 8.

[Stratmangler]

Given that processing is so cheap nowadays there's not really any reason I can see not to do everything at level 8.

Try it streaming to a Squeezebox Touch, where processing is an issue.
Jerry is using a Squeezebox Touch.

[Covenant]

The touch toolbox guy recommends lower comp
ression

[Stratmangler]

The touch toolbox guy recommends lower compression

Going lower is fine Jerry.
5 was always recommended as the highest level to use by the guys at Slim Devices.

[Markiii]

Try having the server decode and stream PCM to the squeezebox, the difference wasn't subtle

[Rothchild]

Try it streaming to a Squeezebox Touch, where processing is an issue.
Jerry is using a Squeezebox Touch.

But the SBT isn't doing the encoding is it?

[Ali Tait]

No, but it does the decoding, and as the processor is only just enough for what it is asked to do, it is worthwhile doing the decoding on the NAS or computer. As Chris says, on higher compression rates you can get droputs and buffering as the Touch processor tries to keep up.

[lovejoy]

I had problems with this on my SBT which took a little tracking down.

Depending on where I am, sometimes I will rip my CDs using XLD on my Mac, and other times using EAC on my PC - All to FLAC.

I worked out after a bit of listening that my PC rips were sounding better than my FLAC rips when played through my SBT so I set about looking at the config on both, refusing to believe that it could be hardware differences causing rips to sound different. Sure enough, my PC was compressing to FLAC on level 5, but my Mac was set to maximum compression level. Once I'd set the compression level to the same as on the PC, I could no longer tell any difference.

In saying all of that, now that I've set my LMS server to do the FLAC decoding and send the uncompressed PCM to the SBT, the compression level has ceased to be an issue, but I've stuck with level 5 as the difference in resulting filesize is not really causing me any hardship anyway.

[Rothchild]

Thanks for the insight Ali, interesting that these devices are so marginal given that the processing overhead in a FLAC is spent when it's encoded. Neither my phone nor my Raspberry Pi (neither of which are over endowed with processing power) seem to have any issue with FLACs compressed at any level - indeed the Pi manages to transcode those FLACs and stream them to my phone (even over the internet) in a range of formats and bitrates.

[WAD62]

Thanks for the insight Ali, interesting that these devices are so marginal given that the processing overhead in a FLAC is spent when it's encoded. Neither my phone nor my Raspberry Pi (neither of which are over endowed with processing power) seem to have any issue with FLACs compressed at any level - indeed the Pi manages to transcode those FLACs and stream them to my phone (even over the internet) in a range of formats and bitrates.

Compared to the SBTouch cpu the PI is a monster @ 700Mhz...and as for your phone! ;)

The SBTouch is only 500Mhz, and the SB3 250Mhz, so don't go beyond level 5 with them...

http://wiki.slimdevices.com/index.php/Hardware_comparison

[Rothchild]

I guess context is everything, I'd never thought of the pi as a monster! But yeah, you make it seem quite :hotrod:

That table seems to indicate though that the SBT has a dedicated decoder chip as well as a cpu, that should take some of the heat out of it I guess. Level 5 it is SBT owners, better get a bigger hard drive! ;-)

[WAD62]

I guess context is everything, I'd never thought of the pi as a monster! But yeah, you make it seem quite :hotrod:


...I've even got mine to overclock to a mighty 1Ghz :eek: