This makes a lot of sense! The rate that CamillaDSP measured is suspiciously close to this theoretical rate of 104 kHz. Since CamillaDSP seems to run slowly, I'm guessing that samples aren't being lost, but rather sent too slowly to the device (at the maximum supported bandwidth). Then no idea what the device does when it only receives just over half the samples it needs. If it manages to make any sound, it's likely very choppy.
Is it possible to flash a newer firmware?
EDIT: This is taken from the manual of the interface:
Last edited:
Good catch with the manual. Then I do not understand why the USB config specifies the 192kHz samplerate for the 20 channels altset:
I vaguely remember we have already discussed an issue in this thread where selecting the channels count changed the supported frequencies. I cannot find the post, there probably was the corresponding stream0 which showed how the soundcard's supported rates were changing with the selected channels count.
Code:
Interface 1
Altset 1
Format: S24_3LE
Channels: 20
Endpoint: 0x02 (2 OUT) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Sync Endpoint: 0x82 (2 IN)
Sync EP Interface: 1
Sync EP Altset: 1
Implicit Feedback Mode: NoI vaguely remember we have already discussed an issue in this thread where selecting the channels count changed the supported frequencies. I cannot find the post, there probably was the corresponding stream0 which showed how the soundcard's supported rates were changing with the selected channels count.
Here you go. I've switched the interface to 20ch and run lsusb -v:
Code:
Bus 001 Device 007: ID 2a39:3fd9 RME Fireface UCX II (24066911)
Couldn't open device, some information will be missing
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 239 Miscellaneous Device
bDeviceSubClass 2
bDeviceProtocol 1 Interface Association
bMaxPacketSize0 64
idVendor 0x2a39 RME
idProduct 0x3fd9
bcdDevice 3.01
iManufacturer 1 RME
iProduct 2 Fireface UCX II (24066911)
iSerial 3 39FD19CE0FE13C8
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 0x026d
bNumInterfaces 4
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xc0
Self Powered
MaxPower 100mA
Interface Association:
bLength 8
bDescriptorType 11
bFirstInterface 0
bInterfaceCount 3
bFunctionClass 1 Audio
bFunctionSubClass 0
bFunctionProtocol 32
iFunction 0
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 0
bInterfaceClass 1 Audio
bInterfaceSubClass 1 Control Device
bInterfaceProtocol 32
iInterface 0
AudioControl Interface Descriptor:
bLength 9
bDescriptorType 36
bDescriptorSubtype 1 (HEADER)
bcdADC 2.00
bCategory 8
wTotalLength 0x004b
bmControls 0x00
AudioControl Interface Descriptor:
bLength 8
bDescriptorType 36
bDescriptorSubtype 10 (CLOCK_SOURCE)
bClockID 1
bmAttributes 3 Internal programmable clock
bmControls 0x03
Clock Frequency Control (read/write)
bAssocTerminal 0
iClockSource 0
AudioControl Interface Descriptor:
bLength 17
bDescriptorType 36
bDescriptorSubtype 2 (INPUT_TERMINAL)
bTerminalID 3
wTerminalType 0x0101 USB Streaming
bAssocTerminal 0
bCSourceID 1
bNrChannels 20
bmChannelConfig 0x00000000
iChannelNames 0
bmControls 0x0000
iTerminal 0
AudioControl Interface Descriptor:
bLength 17
bDescriptorType 36
bDescriptorSubtype 2 (INPUT_TERMINAL)
bTerminalID 5
wTerminalType 0x0603 Line Connector
bAssocTerminal 0
bCSourceID 1
bNrChannels 20
bmChannelConfig 0x00000000
iChannelNames 0
bmControls 0x0000
iTerminal 0
AudioControl Interface Descriptor:
bLength 12
bDescriptorType 36
bDescriptorSubtype 3 (OUTPUT_TERMINAL)
bTerminalID 4
wTerminalType 0x0301 Speaker
bAssocTerminal 0
bSourceID 3
bCSourceID 1
bmControls 0x0000
iTerminal 0
AudioControl Interface Descriptor:
bLength 12
bDescriptorType 36
bDescriptorSubtype 3 (OUTPUT_TERMINAL)
bTerminalID 6
wTerminalType 0x0101 USB Streaming
bAssocTerminal 0
bSourceID 5
bCSourceID 1
bmControls 0x0000
iTerminal 0
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 0
bNumEndpoints 0
bInterfaceClass 1 Audio
bInterfaceSubClass 2 Streaming
bInterfaceProtocol 32
iInterface 0
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 1
bNumEndpoints 2
bInterfaceClass 1 Audio
bInterfaceSubClass 2 Streaming
bInterfaceProtocol 32
iInterface 0
AudioStreaming Interface Descriptor:
bLength 16
bDescriptorType 36
bDescriptorSubtype 1 (AS_GENERAL)
bTerminalLink 3
bmControls 0x00
bFormatType 1
bmFormats 0x00000001
PCM
bNrChannels 20
bmChannelConfig 0x00000000
iChannelNames 0
AudioStreaming Interface Descriptor:
bLength 6
bDescriptorType 36
bDescriptorSubtype 2 (FORMAT_TYPE)
bFormatType 1 (FORMAT_TYPE_I)
bSubslotSize 3
bBitResolution 24
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x030c 1x 780 bytes
bInterval 1
AudioStreaming Endpoint Descriptor:
bLength 8
bDescriptorType 37
bDescriptorSubtype 1 (EP_GENERAL)
bmAttributes 0x00
bmControls 0x00
bLockDelayUnits 0 Undefined
wLockDelay 0x0000
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 17
Transfer Type Isochronous
Synch Type None
Usage Type Feedback
wMaxPacketSize 0x0004 1x 4 bytes
bInterval 4
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 2
bNumEndpoints 2
bInterfaceClass 1 Audio
bInterfaceSubClass 2 Streaming
bInterfaceProtocol 32
iInterface 0
AudioStreaming Interface Descriptor:
bLength 16
bDescriptorType 36
bDescriptorSubtype 1 (AS_GENERAL)
bTerminalLink 3
bmControls 0x00
bFormatType 1
bmFormats 0x00000001
PCM
bNrChannels 16
bmChannelConfig 0x00000003
Front Left (FL)
Front Right (FR)
iChannelNames 0
AudioStreaming Interface Descriptor:
bLength 6
bDescriptorType 36
bDescriptorSubtype 2 (FORMAT_TYPE)
bFormatType 1 (FORMAT_TYPE_I)
bSubslotSize 3
bBitResolution 24
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x0270 1x 624 bytes
bInterval 1
AudioStreaming Endpoint Descriptor:
bLength 8
bDescriptorType 37
bDescriptorSubtype 1 (EP_GENERAL)
bmAttributes 0x00
bmControls 0x00
bLockDelayUnits 0 Undefined
wLockDelay 0x0000
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 17
Transfer Type Isochronous
Synch Type None
Usage Type Feedback
wMaxPacketSize 0x0004 1x 4 bytes
bInterval 4
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 3
bNumEndpoints 2
bInterfaceClass 1 Audio
bInterfaceSubClass 2 Streaming
bInterfaceProtocol 32
iInterface 0
AudioStreaming Interface Descriptor:
bLength 16
bDescriptorType 36
bDescriptorSubtype 1 (AS_GENERAL)
bTerminalLink 3
bmControls 0x00
bFormatType 1
bmFormats 0x00000001
PCM
bNrChannels 14
bmChannelConfig 0x00000003
Front Left (FL)
Front Right (FR)
iChannelNames 0
AudioStreaming Interface Descriptor:
bLength 6
bDescriptorType 36
bDescriptorSubtype 2 (FORMAT_TYPE)
bFormatType 1 (FORMAT_TYPE_I)
bSubslotSize 3
bBitResolution 24
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x0a4c 2x 588 bytes
bInterval 1
AudioStreaming Endpoint Descriptor:
bLength 8
bDescriptorType 37
bDescriptorSubtype 1 (EP_GENERAL)
bmAttributes 0x00
bmControls 0x00
bLockDelayUnits 0 Undefined
wLockDelay 0x0000
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 17
Transfer Type Isochronous
Synch Type None
Usage Type Feedback
wMaxPacketSize 0x0004 1x 4 bytes
bInterval 4
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 4
bNumEndpoints 2
bInterfaceClass 1 Audio
bInterfaceSubClass 2 Streaming
bInterfaceProtocol 32
iInterface 0
AudioStreaming Interface Descriptor:
bLength 16
bDescriptorType 36
bDescriptorSubtype 1 (AS_GENERAL)
bTerminalLink 3
bmControls 0x00
bFormatType 1
bmFormats 0x00000001
PCM
bNrChannels 8
bmChannelConfig 0x00000003
Front Left (FL)
Front Right (FR)
iChannelNames 0
AudioStreaming Interface Descriptor:
bLength 6
bDescriptorType 36
bDescriptorSubtype 2 (FORMAT_TYPE)
bFormatType 1 (FORMAT_TYPE_I)
bSubslotSize 3
bBitResolution 24
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x0258 1x 600 bytes
bInterval 1
AudioStreaming Endpoint Descriptor:
bLength 8
bDescriptorType 37
bDescriptorSubtype 1 (EP_GENERAL)
bmAttributes 0x00
bmControls 0x00
bLockDelayUnits 0 Undefined
wLockDelay 0x0000
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 17
Transfer Type Isochronous
Synch Type None
Usage Type Feedback
wMaxPacketSize 0x0004 1x 4 bytes
bInterval 4
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 2
bAlternateSetting 0
bNumEndpoints 0
bInterfaceClass 1 Audio
bInterfaceSubClass 2 Streaming
bInterfaceProtocol 32
iInterface 0
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 2
bAlternateSetting 1
bNumEndpoints 1
bInterfaceClass 1 Audio
bInterfaceSubClass 2 Streaming
bInterfaceProtocol 32
iInterface 0
AudioStreaming Interface Descriptor:
bLength 16
bDescriptorType 36
bDescriptorSubtype 1 (AS_GENERAL)
bTerminalLink 6
bmControls 0x00
bFormatType 1
bmFormats 0x00000001
PCM
bNrChannels 20
bmChannelConfig 0x00000000
iChannelNames 0
AudioStreaming Interface Descriptor:
bLength 6
bDescriptorType 36
bDescriptorSubtype 2 (FORMAT_TYPE)
bFormatType 1 (FORMAT_TYPE_I)
bSubslotSize 3
bBitResolution 24
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x030c 1x 780 bytes
bInterval 1
AudioStreaming Endpoint Descriptor:
bLength 8
bDescriptorType 37
bDescriptorSubtype 1 (EP_GENERAL)
bmAttributes 0x00
bmControls 0x00
bLockDelayUnits 0 Undefined
wLockDelay 0x0000
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 2
bAlternateSetting 2
bNumEndpoints 1
bInterfaceClass 1 Audio
bInterfaceSubClass 2 Streaming
bInterfaceProtocol 32
iInterface 0
AudioStreaming Interface Descriptor:
bLength 16
bDescriptorType 36
bDescriptorSubtype 1 (AS_GENERAL)
bTerminalLink 6
bmControls 0x00
bFormatType 1
bmFormats 0x00000001
PCM
bNrChannels 16
bmChannelConfig 0x00000000
iChannelNames 0
AudioStreaming Interface Descriptor:
bLength 6
bDescriptorType 36
bDescriptorSubtype 2 (FORMAT_TYPE)
bFormatType 1 (FORMAT_TYPE_I)
bSubslotSize 3
bBitResolution 24
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x0270 1x 624 bytes
bInterval 1
AudioStreaming Endpoint Descriptor:
bLength 8
bDescriptorType 37
bDescriptorSubtype 1 (EP_GENERAL)
bmAttributes 0x00
bmControls 0x00
bLockDelayUnits 0 Undefined
wLockDelay 0x0000
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 2
bAlternateSetting 3
bNumEndpoints 1
bInterfaceClass 1 Audio
bInterfaceSubClass 2 Streaming
bInterfaceProtocol 32
iInterface 0
AudioStreaming Interface Descriptor:
bLength 16
bDescriptorType 36
bDescriptorSubtype 1 (AS_GENERAL)
bTerminalLink 6
bmControls 0x00
bFormatType 1
bmFormats 0x00000001
PCM
bNrChannels 14
bmChannelConfig 0x00000000
iChannelNames 0
AudioStreaming Interface Descriptor:
bLength 6
bDescriptorType 36
bDescriptorSubtype 2 (FORMAT_TYPE)
bFormatType 1 (FORMAT_TYPE_I)
bSubslotSize 3
bBitResolution 24
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x0a4c 2x 588 bytes
bInterval 1
AudioStreaming Endpoint Descriptor:
bLength 8
bDescriptorType 37
bDescriptorSubtype 1 (EP_GENERAL)
bmAttributes 0x00
bmControls 0x00
bLockDelayUnits 0 Undefined
wLockDelay 0x0000
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 2
bAlternateSetting 4
bNumEndpoints 1
bInterfaceClass 1 Audio
bInterfaceSubClass 2 Streaming
bInterfaceProtocol 32
iInterface 0
AudioStreaming Interface Descriptor:
bLength 16
bDescriptorType 36
bDescriptorSubtype 1 (AS_GENERAL)
bTerminalLink 6
bmControls 0x00
bFormatType 1
bmFormats 0x00000001
PCM
bNrChannels 8
bmChannelConfig 0x00000000
iChannelNames 0
AudioStreaming Interface Descriptor:
bLength 6
bDescriptorType 36
bDescriptorSubtype 2 (FORMAT_TYPE)
bFormatType 1 (FORMAT_TYPE_I)
bSubslotSize 3
bBitResolution 24
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x0258 1x 600 bytes
bInterval 1
AudioStreaming Endpoint Descriptor:
bLength 8
bDescriptorType 37
bDescriptorSubtype 1 (EP_GENERAL)
bmAttributes 0x00
bmControls 0x00
bLockDelayUnits 0 Undefined
wLockDelay 0x0000
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 3
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 1 Audio
bInterfaceSubClass 3 MIDI Streaming
bInterfaceProtocol 0
iInterface 2
MIDIStreaming Interface Descriptor:
bLength 7
bDescriptorType 36
bDescriptorSubtype 1 (HEADER)
bcdADC 1.00
wTotalLength 0x0061
MIDIStreaming Interface Descriptor:
bLength 9
bDescriptorType 36
bDescriptorSubtype 3 (MIDI_OUT_JACK)
bJackType 1 Embedded
bJackID 3
bNrInputPins 1
baSourceID( 0) 2
BaSourcePin( 0) 1
iJack 4
MIDIStreaming Interface Descriptor:
bLength 6
bDescriptorType 36
bDescriptorSubtype 2 (MIDI_IN_JACK)
bJackType 2 External
bJackID 2
iJack 4
MIDIStreaming Interface Descriptor:
bLength 9
bDescriptorType 36
bDescriptorSubtype 3 (MIDI_OUT_JACK)
bJackType 1 Embedded
bJackID 7
bNrInputPins 1
baSourceID( 0) 6
BaSourcePin( 0) 1
iJack 5
MIDIStreaming Interface Descriptor:
bLength 6
bDescriptorType 36
bDescriptorSubtype 2 (MIDI_IN_JACK)
bJackType 2 External
bJackID 6
iJack 5
MIDIStreaming Interface Descriptor:
bLength 6
bDescriptorType 36
bDescriptorSubtype 2 (MIDI_IN_JACK)
bJackType 1 Embedded
bJackID 1
iJack 4
MIDIStreaming Interface Descriptor:
bLength 9
bDescriptorType 36
bDescriptorSubtype 3 (MIDI_OUT_JACK)
bJackType 2 External
bJackID 4
bNrInputPins 1
baSourceID( 0) 1
BaSourcePin( 0) 1
iJack 4
MIDIStreaming Interface Descriptor:
bLength 6
bDescriptorType 36
bDescriptorSubtype 2 (MIDI_IN_JACK)
bJackType 1 Embedded
bJackID 5
iJack 5
MIDIStreaming Interface Descriptor:
bLength 9
bDescriptorType 36
bDescriptorSubtype 3 (MIDI_OUT_JACK)
bJackType 2 External
bJackID 8
bNrInputPins 1
baSourceID( 0) 5
BaSourcePin( 0) 1
iJack 5
Endpoint Descriptor:
bLength 9
bDescriptorType 5
bEndpointAddress 0x07 EP 7 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
bRefresh 0
bSynchAddress 0
MIDIStreaming Endpoint Descriptor:
bLength 6
bDescriptorType 37
bDescriptorSubtype 1 (GENERAL)
bNumEmbMIDIJack 2
baAssocJackID( 0) 1
baAssocJackID( 1) 5
Endpoint Descriptor:
bLength 9
bDescriptorType 5
bEndpointAddress 0x86 EP 6 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
bRefresh 0
bSynchAddress 0
MIDIStreaming Endpoint Descriptor:
bLength 6
bDescriptorType 37
bDescriptorSubtype 1 (GENERAL)
bNumEmbMIDIJack 2
baAssocJackID( 0) 3
baAssocJackID( 1) 7
Code:
ubuntu@ubuntu:/usr/local/etc/camilladsp$ sudo cat /proc/asound/II24066911/stream0
RME Fireface UCX II (24066911) at usb-0000:01:00.0-1.3, high speed : USB Audio
Playback:
Status: Running
Interface = 1
Altset = 1
Packet Size = 780
Momentary freq = 192000 Hz (0x18.0000)
Interface 1
Altset 1
Format: S24_3LE
Channels: 20
Endpoint: 0x02 (2 OUT) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Sync Endpoint: 0x82 (2 IN)
Sync EP Interface: 1
Sync EP Altset: 1
Implicit Feedback Mode: No
Interface 1
Altset 2
Format: S24_3LE
Channels: 16
Endpoint: 0x02 (2 OUT) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Sync Endpoint: 0x82 (2 IN)
Sync EP Interface: 1
Sync EP Altset: 2
Implicit Feedback Mode: No
Interface 1
Altset 3
Format: S24_3LE
Channels: 14
Endpoint: 0x02 (2 OUT) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Channel map: FL FR -- -- -- -- -- -- -- -- -- -- -- --
Sync Endpoint: 0x82 (2 IN)
Sync EP Interface: 1
Sync EP Altset: 3
Implicit Feedback Mode: No
Interface 1
Altset 4
Format: S24_3LE
Channels: 8
Endpoint: 0x02 (2 OUT) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Channel map: FL FR -- -- -- -- -- --
Sync Endpoint: 0x82 (2 IN)
Sync EP Interface: 1
Sync EP Altset: 4
Implicit Feedback Mode: No
Capture:
Status: Stop
Interface 2
Altset 1
Format: S24_3LE
Channels: 20
Endpoint: 0x81 (1 IN) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Interface 2
Altset 2
Format: S24_3LE
Channels: 16
Endpoint: 0x81 (1 IN) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Interface 2
Altset 3
Format: S24_3LE
Channels: 14
Endpoint: 0x81 (1 IN) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Channel map: FL FR FC LFE RL RR FLC FRC RC SL SR TC TFL TFC
Interface 2
Altset 4
Format: S24_3LE
Channels: 8
Endpoint: 0x81 (1 IN) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Channel map: FL FR FC LFE RL RR FLC FRCAnd yes, the sound is highly distorted.
Does this information confirm your thoughts?
I checked I had the latest firmware before starting.
I'd also read that in the manual, and read it as a limitation of the iOS interface rather than the capability of the device itself when in Class Compliant mode.
I may have got this wrong, but wouldn't 14 channels at 192kHz also exceed the bandwidth limit?
The limitation is that iOS can't switch to a different alternate setting, so it's locked to the first one which is 20 channels (and 96 kHz maximum).
14 channels at 192 kHz should be possible, if it sets the packet size to 1008 bytes:
jahnanon: Thanks for the dumps.
The USB configuration (lsusb) is identical for your last and previous dumps. What was the actual difference in the soundcard setup between the two dumps?
It must be when basically 50% of samples are missing. IMO alsa keeps sending samples at max consumption rate of 780 bytes/microframe = 780/3/20 = 13 samples per channel per packet. However, the reclocking FIFO in the soundcard is being read by the 192kHz DAC clock at rate 192k/8k= 24 samples per channel per packet. The FIFO is constantly underflown.
Theoretically that should result in the feedback requesting as much extra data as possible, but the feedback value is unchanged:
Most likely the incoming bitrate is so much off from the expected one that the USB feedback code in the soundcard ignores the value and disables the feedback control.
Yes. 192k * 3 * 14 / 8k = 1008 bytes per packet, that would fit the 1024 limit. But USB async must reserve bandwidth for at least one more audioframe per packet so that slightly higher rate can be requested by the feedback. That makes 1008 + 3 *14 = 1050 bytes which already does not fit. E.g. the USB audio gadget in default setup allows increase of 5 promiles above the samplerate, which would be 192000 * 0.005 /8000= 0.12 audioframe of headroom per microframe => rounded to one extra audioframe (1050bytes).
So only the 8ch altsetting fits the 192kHz bandwidth.
The USB configuration (lsusb) is identical for your last and previous dumps. What was the actual difference in the soundcard setup between the two dumps?
It must be when basically 50% of samples are missing. IMO alsa keeps sending samples at max consumption rate of 780 bytes/microframe = 780/3/20 = 13 samples per channel per packet. However, the reclocking FIFO in the soundcard is being read by the 192kHz DAC clock at rate 192k/8k= 24 samples per channel per packet. The FIFO is constantly underflown.
Theoretically that should result in the feedback requesting as much extra data as possible, but the feedback value is unchanged:
Code:
Momentary freq = 192000 Hz (0x18.0000)Most likely the incoming bitrate is so much off from the expected one that the USB feedback code in the soundcard ignores the value and disables the feedback control.
Yes. 192k * 3 * 14 / 8k = 1008 bytes per packet, that would fit the 1024 limit. But USB async must reserve bandwidth for at least one more audioframe per packet so that slightly higher rate can be requested by the feedback. That makes 1008 + 3 *14 = 1050 bytes which already does not fit. E.g. the USB audio gadget in default setup allows increase of 5 promiles above the samplerate, which would be 192000 * 0.005 /8000= 0.12 audioframe of headroom per microframe => rounded to one extra audioframe (1050bytes).
So only the 8ch altsetting fits the 192kHz bandwidth.
Thanks guys - it's been very interesting and I think I understand the bandwidth limitations of the device. For my purposes 8 channels is plenty, but it's good to know why the initial setting failed.
I'll drop an email to RME referencing this thread to let them know. As a company they seem very thorough in their approach, so I'm a little surprised that they've let this slip through.
I'll drop an email to RME referencing this thread to let them know. As a company they seem very thorough in their approach, so I'm a little surprised that they've let this slip through.
I think I see where the problem is. Look at the lsusb -v altsetting 3 for 14 channels:
2 x 588 bytes, not like for 16 and 20 channels:
Let's do the math:
2 x 588 x 8000 / 14 / 3 = 224kHz max. samplerate = 192kHz + healthy async headroom.
For 8ch altsetting the config is
1 x 600 x 8000 / 8 / 3 = 200kHz, nice.
Now what about using 2 x 780 for 20ch:
2 x 780 x 8000 / 20 / 3 = 208kHz
And 2 x 624 for 16ch:
2 x 624 x 8000 / 16 / 3 = 208kHz
My 2 cents this is the bug in the firmware - incorrect maxpacketsize format for the 20 and 16ch altsettings.
johnanon: Please can you test 14ch playback at 192kHz (where the maxpacketsize is reported correctly) and post stream0 here? If it works OK, IMO a simple quirk in the alsa usb driver could fake/fix the reported maxpacketsize and the device could work as intended up to 20 channels. Or a fixed firmware, of course.
Code:
wMaxPacketSize 0x0a4c 2x 588 bytes2 x 588 bytes, not like for 16 and 20 channels:
Code:
wMaxPacketSize 0x030c 1x 780 bytes
...
wMaxPacketSize 0x0270 1x 624 bytesLet's do the math:
2 x 588 x 8000 / 14 / 3 = 224kHz max. samplerate = 192kHz + healthy async headroom.
For 8ch altsetting the config is
Code:
wMaxPacketSize 0x0258 1x 600 bytes1 x 600 x 8000 / 8 / 3 = 200kHz, nice.
Now what about using 2 x 780 for 20ch:
2 x 780 x 8000 / 20 / 3 = 208kHz
And 2 x 624 for 16ch:
2 x 624 x 8000 / 16 / 3 = 208kHz
My 2 cents this is the bug in the firmware - incorrect maxpacketsize format for the 20 and 16ch altsettings.
johnanon: Please can you test 14ch playback at 192kHz (where the maxpacketsize is reported correctly) and post stream0 here? If it works OK, IMO a simple quirk in the alsa usb driver could fake/fix the reported maxpacketsize and the device could work as intended up to 20 channels. Or a fixed firmware, of course.
Sorry for the delay - just got round to this now. Sounds fine running 14 channels. Looks like you were right - here's the stream0 response:
Code:
ubuntu@ubuntu:/usr/local/etc/camilladsp/logs$ cat /proc/asound/II24066911/stream0
RME Fireface UCX II (24066911) at usb-0000:01:00.0-1.3, high speed : USB Audio
Playback:
Status: Running
Interface = 1
Altset = 3
Packet Size = 1176
Momentary freq = 192024 Hz (0x18.00c6)
Feedback Format = 16.16
Interface 1
Altset 1
Format: S24_3LE
Channels: 20
Endpoint: 0x02 (2 OUT) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Sync Endpoint: 0x82 (2 IN)
Sync EP Interface: 1
Sync EP Altset: 1
Implicit Feedback Mode: No
Interface 1
Altset 2
Format: S24_3LE
Channels: 16
Endpoint: 0x02 (2 OUT) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Sync Endpoint: 0x82 (2 IN)
Sync EP Interface: 1
Sync EP Altset: 2
Implicit Feedback Mode: No
Interface 1
Altset 3
Format: S24_3LE
Channels: 14
Endpoint: 0x02 (2 OUT) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Channel map: FL FR -- -- -- -- -- -- -- -- -- -- -- --
Sync Endpoint: 0x82 (2 IN)
Sync EP Interface: 1
Sync EP Altset: 3
Implicit Feedback Mode: No
Interface 1
Altset 4
Format: S24_3LE
Channels: 8
Endpoint: 0x02 (2 OUT) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Channel map: FL FR -- -- -- -- -- --
Sync Endpoint: 0x82 (2 IN)
Sync EP Interface: 1
Sync EP Altset: 4
Implicit Feedback Mode: No
Capture:
Status: Stop
Interface 2
Altset 1
Format: S24_3LE
Channels: 20
Endpoint: 0x81 (1 IN) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Interface 2
Altset 2
Format: S24_3LE
Channels: 16
Endpoint: 0x81 (1 IN) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Interface 2
Altset 3
Format: S24_3LE
Channels: 14
Endpoint: 0x81 (1 IN) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Channel map: FL FR FC LFE RL RR FLC FRC RC SL SR TC TFL TFC
Interface 2
Altset 4
Format: S24_3LE
Channels: 8
Endpoint: 0x81 (1 IN) (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Bits: 24
Channel map: FL FR FC LFE RL RR FLC FRC
Wow I am learning a lot here. I have yet to purchase an interface I am hoping to learn enough from you guys to be able to learn how to use something with at least 20 channels. I am looking to make a reference CBT curved line array for my listening room. They need 10 channels on each side. I repeatedly see the use of LINUX. I am guessing this is what Is the most versatile and stable operating system to use CamillaDSP in?
johnanon: Excellent. That means the wMaxPacketSize should have value 1 at bit 11 (0-based count), meaning 1 additional transaction (chapter 9.6.6 of https://edg.uchicago.edu/~tang/USB/usb_20.pdf )
For 20ch:
0x030c -> 0x0b0c
For 16ch:
0x0270 -> 0x0a70
Please can you ask RME about options for fixing their firmware? I wonder how such bug made it through...
For 20ch:
0x030c -> 0x0b0c
For 16ch:
0x0270 -> 0x0a70
Please can you ask RME about options for fixing their firmware? I wonder how such bug made it through...
There is no simple answer to which platform is the best, it depends a lot on your preferences and what you want to do.
In terms of stability there should not be any significant difference between Linux, Windows and macOS.
Of course there may be bugs sometimes that affect only one system. That's least likely to affect Alsa since it's the most mature backend, while both WASAPI and CoreAudio are quite new. Then again, those two are in some ways better since I learned a lot along the way. At some point I will rewrite the Alsa and File backends to use some of the new concepts. At that point WASAPI&CoreAudio will become the most mature.. 🙂
I posted a short notice to UCX II USB configuration issue for 20ch and 16ch wMaxPacketSize? (Page 1) — FireWire & USB series — RME User Forum , IIUC RME people read that forum.
New preview of v1.0.0!
Get it from: Release v1.0.0-alpha2 * HEnquist/camilladsp * GitHub
It has various bugfixes and improvements from alpha1, for example better error management and support for hog mode on macOS.
The documentation is in branch "next100": camilladsp/README.md at next100 * HEnquist/camilladsp * GitHub
Get it from: Release v1.0.0-alpha2 * HEnquist/camilladsp * GitHub
It has various bugfixes and improvements from alpha1, for example better error management and support for hog mode on macOS.
The documentation is in branch "next100": camilladsp/README.md at next100 * HEnquist/camilladsp * GitHub
Excellent. I've contacted RME and sent them a link to this discussion. I've yet to hear back.
johnanon: So RME says the current setup is intentional, to support iOS which presumably does not work with high-speed (multiple transactions). I do not understand why 20ch/16ch and not 14ch but it's not for me to call a shot.
If you want to try a kernel quirk, to test whether faking the max packet size would fix the 192kHz playback for 20ch and 16ch, let me know in PM. IF it turns out to work then new kernel versions could support full hardware features of that device.
If you want to try a kernel quirk, to test whether faking the max packet size would fix the 192kHz playback for 20ch and 16ch, let me know in PM. IF it turns out to work then new kernel versions could support full hardware features of that device.
Hi Michael
I'm testing an RME UCX II at the moment and I wonder if you'd help me with understanding the CamillaDSP/ALSA configuration you use to capture a stream from the soundcard? I'm going to connect my CD's optical to the RME, and that physical input maps to channels 13/14. Any quick pointer you can give me will, no doubt, save me lots of time spent fiddling at this end.
I decided to give the RME a whirl for two reasons. First it supports SPDIF coax at 192kHz, which is the native operational frequency of the LS50W2 that I'm driving (although I accept that this may be of limited theoretical rather than audible significance!). Secondly, I think it offers a route to control the interface using MIDI out of nodeRED so I can automate swapping between 192kHz for streaming content, and occasional CD use by my wife at 44.1kHz.
I had no idea when I started this exploration with CamillaDSP how far it would lead. It's amazing software - and unlocks far too many possibilities!
It's about placing the blocking ALSA read/write in a thread of its own. This avoids some problems that occur when the read/write takes longer than expected. Normally that isn't an issue, but when using quirky devices like for example many spdif inputs this means the quirks can be handled in a better way.
The File backend will get the same treatment and it means that pipes can be better supported. The current implementation doesn't work well when reading from a pipe and the sending application stops sending data (but still keeps the pipe open). Some player apps do that when playback is paused.