Bugzilla – Bug 15119
SB Server should resample unsupported sample rates
Last modified: 2011-11-06 23:22:37 UTC
Ticket #091115-001466 Transporter fw 80 41.0 kHz 16 bit FLAC files When customer plays 16 bit 41.0 kHz files, they play too fast. Customer sent 3 files, an we were able to recreate the issue here. **These files play fine on Classic and Boom*** Issue only occurs on Transporters Open the Squeezebox Server web control -Click on Settings (bottom right hand corner) -Go to the advanced tab -Change the dropdown menu to File Types -Locate the FLAC section, and change the dropdown from "Native" to "Disabled" -Click the Apply button then click Close (bottom right hand corner) Re-choose the file whether on the Transporter or SB Server. I will play correctly. Spoke with QA, advised to create a bug. Thanks, LaRon
Files too large to attached. Please download them via the following link. https://rcpt.yousendit.com/776644632/03f5b4e28d58c95a25fb9dfa8621949a Thanks, LaRon
Yeah, the real fix is for the user to re-rip at the correct sample rate. Nobody should be using 41 kHz. Actually I'm a bit surprised we can play a 41 kHz file. However, I would expect sox resampling to kick in here to resample this to 44.1, but it probably doesn't because we only coded for the downsampling case I think. Alan: any ideas?
Yes, we only coded for the downsampling case - that is, when the sample-rate of the file is greater than the maximum rate supported by the player. Also, I believe that we only support 'standard' sample rates: 8000, 11025, 16000, 22050, 24000, 32000, 44100, 48000, 88200, 96000.
From the product documentation: Sample rates: 44.1kHz, 48kHz, 88.2kHz, 96kHz
Why do they play correctly on SB3 and Boom? Different internal clocks or is it a complete mystery?
I don't agree that this should be a wont fix. We should at least fail gracefully instead of playing the flac at the wrong speed.
I seem to recall Sean put something into the SB2/3 firmware to play at arbitrary speeds for a customer who was interested in using the products for transcription. My guess would be that there wasn't room for both that AND Sean's audiophile magic in the Transporter FW. :) I will poke around a bit and try to find any more info. Steven and LaRon, does the file play correctly if you DON'T go out of your way to disable transcoding as LaRon describes in step 1?
Hello Chris, No, the files play like Alvin and the Chipmunks.. to describe it best. Thanks, LaRon
So it turns out that transporter is playing the 41 kHz flac as 88.2 kHz and the classic is playing the track at 44.1 kHz. So neither player is playing the track at the right speed. While the classic is playing about 7% fast the transporter is playing about 215% fast which is hard to miss indeed. I also tested the track on touch and even tough the output is playing at 44.1 kHz it is playing at the right speed. Does the touch have the ability to resample or is sox involved and I just don't realize it? Anyway I would think a simple solution to this issue would be to define all of the sample rates that the players support properly and any track outside of those rates gets resampled on the server or just not play. Oh and I decoded the flac to wav and I get the same result so this does not seem format specific. Also it is a valid flac file as well. Alan, what do you think?
(In reply to comment #9) > I also tested the track on touch and even tough the output is playing at 44.1 > kHz it is playing at the right speed. Does the touch have the ability to > resample or is sox involved and I just don't realize it? Playing FLAC, but not PCM, Touch may have the ability to resample in the audio driver. I do not know how good or CPU-intensive that resampling is.
Anyone interested in developing an enhancement should probably look at Slim::Player::CapabilitiesHelper::samplerateLimit
Do you know why this is assigned to you, LaRon?
(In reply to comment #12) > Do you know why this is assigned to you, LaRon? Hello Chris, I have no idea. Thanks, LaRon
Is it even possible to disable transcoding on a per-player basis? I don't know what is the right solution for this problem.
Chris, I don't understand that last comment.
Sorry, maybe I'm over-analyzing this bug. * The problem is: 41KHz files play at the wrong sample rate on the Transporter. * The workaround is (according to LaRon in the original comment) to change the 'File Types' settings. Maybe that is the fix. I don't know.
The issue is that the products do not support playing files with non-standard sample-rates - this is fine. The bug is that, instead of refusing to play them, it plays them badly. I would call this a very minor bug indeed.
Unassigned bugs cannot have a priority.