Bug #5561
SNR 0%
0%
Description
SNR is displayed as 0%, which is incorrect since I play TV in Kodi without problems.
Computer with TVHeadend: Raspberry Pi 3b
TV Tuner: Media-tech MT4171
OS: Raspbian Jessie
Tvheadend: 4.2.6-84~g81f56cc
Files
History
Updated by saen acro over 5 years ago
This is a driver problem.
See if with femon show anything else.
Updated by iw is over 5 years ago
Info about the computer and software: https://myserver.opentechnologies.pl/en/technical-documentation/
Additionally today I have updated TVheadend from 4.0.8 to 4.2.6 using 'deb https://dl.bintray.com/mpmc/deb raspbianjessie stable-4.2' repository as described on https://tvheadend.org/projects/tvheadend/wiki/AptRepositories
Each of the three DVB-T tuners has the following additional settings as before updating TVH:
- Configuration > DVB Inputs > TV Adapters > Force old status = yes (otherwise TV signal strength and quality are shown incorrectly, tvheadend.org/issues/2759 bug)
- Configuration > DVB Inputs > TV Adapters > Power Save = yes
I noticed this error 3 times today - every time after restarting the computer, which I also restarted 3 times. After several minutes (up to 30 minutes) SNR is displayed properly. Restarting Tvheadend doesn't change it - it is still displayed correctly or incorrectly - as before restarting TVheadned. I didn't notice this issue before updating Tvheadend.
femon output is the same after regardless the TVH output:
pi@raspberrypi:~ $ femon
FE: Afatech AF9033 (DVB-T) (DVBT)
status SCVYL | signal e665 | snr f7ff | ber 00000000 | unc 0000000b | FE_HAS_LOCK
Updated by iw is over 5 years ago
I meant that it seems that femon works properly - values snr and others seem to change properly as the signal in antenna changes
Updated by iw is over 5 years ago
I noticed that Signal Strength also is displayed incorrectly in TVheadend admin similarly to SNR.
Updated by saen acro over 5 years ago
femon -H
- reporting signal in dBm instead of percents
- reporting SNR in EsNo instead of percents
Updated by iw is over 5 years ago
- File 20190227_180152.jpg 20190227_180152.jpg added
Screenshot is in the attachment.
Updated by saen acro over 5 years ago
If you use this setup
BER is normal never ever cut lan cables, twisted cables need to be twisted else work as 100-150 mhz jammer.
do you play with
Signal multiplier:
SNR multiplier:
p.s.
DiBcom 3000MC/P have same problem
Updated by iw is over 5 years ago
I use this one:
So is it a bug in Tvheadend or in tuner driver?
Updated by saen acro over 5 years ago
Problem is maybe how TVH read/represent status data from driver.
Updated by Jaroslav Kysela over 5 years ago
Add this patch to the tvheadend, so you can dump the read values from the driver:
diff --git a/src/input/mpegts/linuxdvb/linuxdvb_frontend.c b/src/input/mpegts/linuxdvb/linuxdvb_frontend.c index 19aa2fcc7..2e90a3e90 100644 --- a/src/input/mpegts/linuxdvb/linuxdvb_frontend.c +++ b/src/input/mpegts/linuxdvb/linuxdvb_frontend.c @@ -1199,6 +1199,7 @@ linuxdvb_frontend_monitor ( void *aux ) } if (ioctl_check(lfe, 3) && !ioctl(lfe->lfe_fe_fd, FE_READ_SNR, &u16)) { mmi->tii_stats.snr_scale = SIGNAL_STATUS_SCALE_RELATIVE; + tvhinfo(LS_LINUXDVB, "SNR value %04x multiplier %d", u16, lfe->lfe_snr_multiplier); mmi->tii_stats.snr = sig_multiply(u16, lfe->lfe_snr_multiplier); } else {
Check the linuxdvb log.
Updated by da h4xX0rz1sT over 5 years ago
- File SNR_db_versus_percent.png SNR_db_versus_percent.png added
- File Kodi18.1_SNR_0percent_screenshot000.png Kodi18.1_SNR_0percent_screenshot000.png added
I have a similar issue.
With my DVB-T2 USB sticks (Panasonic MN88473) the SNR value is shown as dB instead percent in tvh (4.3-1771~gd2405f298) web interface. When using it with my Octopus Net DVB-S2, SNR is shown in percent (see first screenshot).
Obviously, Kodi (18.1) pvr.hts does not seem to understand "dB" instead percent, and shows SNR as 0% (see second screenshot).
When using the above patch and setting debug linuxdvb on, there is no output showing that debug line, so it seems that code doesn't get called at all.
HTH,
/HXZ
Updated by iw is over 5 years ago
I don't know how to build TVH on Raspberry Pi. Even if I knew it, I don't know how much time it will take to do this, and I cannot spend too much time on it. Anyway, I noticed that SNR and signal strength are shown correctly after about 25 minutes from the start of Raspberry Pi so I can accept it for now.
Da h4xX0rz1sT, did you set "Configuration > DVB Inputs > TV adapters > Advanced Settings > Force old status" for Panasonic tuners?
Updated by da h4xX0rz1sT over 5 years ago
iw is wrote:
I don't know how to build TVH on Raspberry Pi. Even if I knew it, I don't know how much time it will take to do this, and I cannot spend too much time on it. Anyway, I noticed that SNR and signal strength are shown correctly after about 25 minutes from the start of Raspberry Pi so I can accept it for now.
https://tvheadend.org/projects/tvheadend/wiki/Building
Da h4xX0rz1sT, did you set "Configuration > DVB Inputs > TV adapters > Advanced Settings > Force old status" for Panasonic tuners?
No. The driver does not use old status. If I set that, there is no signal quality and no SNR at all.
HTH,
/HXZ
Updated by da h4xX0rz1sT over 5 years ago
Any chance to get further here?
One might think it's just a cosmetic problem, which is probably somehow true.
For me, most notable problem is, SNR (as dB), and SNR (as percent bar graph) are not easily comparable between tuners.
Sencond, Kodi clients do not show SNR, if value is in dB.
Thx2all,
/HXZ
Updated by da h4xX0rz1sT over 5 years ago
Thx @saen acro, got this here:
lsd@tvhserver:~# femon -a 2 -H opening frontend failed: No such file or directory # in use by TVheadend lsd@tvhserver:~# femon -a 1 -H FE: Realtek RTL2832 (DVB-T) (DVBT) Problem retrieving frontend information: Operation not supported # BER and UNC don't come out of this driver correctly status | signal 0% | snr 0% | ber 1 | unc 2109 | Problem retrieving frontend information: Operation not supported status | signal 0% | snr 0% | ber 1 | unc 2109 | Problem retrieving frontend information: Operation not supported status | signal 0% | snr 0% | ber 1 | unc 2109 | Problem retrieving frontend information: Operation not supported status | signal 0% | snr 0% | ber 1 | unc 2109 | ^C lsd@tvhserver:~# femon -a 0 -H FE: Realtek RTL2832 (DVB-T) (DVBT) Problem retrieving frontend information: Operation not supported status | signal 0% | snr 0% | ber 1 | unc 2109 | Problem retrieving frontend information: Operation not supported status | signal 0% | snr 0% | ber 1 | unc 2109 | Problem retrieving frontend information: Operation not supported status | signal 0% | snr 0% | ber 1 | unc 2109 | Problem retrieving frontend information: Operation not supported status | signal 0% | snr 0% | ber 1 | unc 2109 |
In TVh log I also see this:
host tvheadend[1337]: linuxdvb: Unable to provide UNC value. host tvheadend[1337]: linuxdvb: Unable to provide BER value.
Doesn't affect operation in any way, but clearly, there is still a driver bug.
/HXZ
Updated by da h4xX0rz1sT over 5 years ago
Without -H:
lsd@tvhserver:~# femon -a 0 FE: Realtek RTL2832 (DVB-T) (DVBT) Problem retrieving frontend information: Operation not supported status | signal 0000 | snr 0000 | ber 00000001 | unc 0000083d | Problem retrieving frontend information: Operation not supported status | signal 0000 | snr 0000 | ber 00000001 | unc 0000083d | Problem retrieving frontend information: Operation not supported status | signal 0000 | snr 0000 | ber 00000001 | unc 0000083d | Problem retrieving frontend information: Operation not supported status | signal 0000 | snr 0000 | ber 00000001 | unc 0000083d | ^C lsd@tvhserver:~# femon -a 1 FE: Realtek RTL2832 (DVB-T) (DVBT) Problem retrieving frontend information: Operation not supported status | signal 0000 | snr 0000 | ber 00000001 | unc 0000083d | Problem retrieving frontend information: Operation not supported status | signal 0000 | snr 0000 | ber 00000001 | unc 0000083d | Problem retrieving frontend information: Operation not supported status | signal 0000 | snr 0000 | ber 00000001 | unc 0000083d | Problem retrieving frontend information: Operation not supported status | signal 0000 | snr 0000 | ber 00000001 | unc 0000083d | ^C lsd@tvhserver:~# femon -a 2 opening frontend failed: No such file or directory # adapter in use
Not saying much...
/HXZ
Updated by saen acro over 5 years ago
Driver problem
https://github.com/ambrosa/DVB-Realtek-RTL2832U-2.2.2-10tuner-mod_kernel-3.0.0
what is result of
modinfo dvb_usb_rtl2832u
Updated by saen acro over 5 years ago
http://superkuh.com/rtlsdr.html
This tuner is real lottery to work as expected.
Switch to other not so cheap brand.
Updated by da h4xX0rz1sT over 5 years ago
Yeah I know these are cheap-ass USB sticks, but they work for me.
The driver has issues, or better said, missing features like no UNC and BER value, but they report signal strength and SNR (see "TVh web GUI" screenshot I posted).
lsd@tvhserver:~# lsmod|grep dvb dvb_usb_rtl28xxu 20480 3 dvb_usb_v2 20480 1 dvb_usb_rtl28xxu lsd@tvhserver:~# modinfo dvb_usb_rtl28xxu filename: /lib/modules/4.14.94-odroidxu4/kernel/drivers/media/usb/dvb-usb-v2/dvb-usb-rtl28xxu.ko license: GPL author: Thomas Mair <[email protected]> author: Antti Palosaari <[email protected]> description: Realtek RTL28xxU DVB USB driver alias: usb:v5654pCA42d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v15F4p0131d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v1B80pD3A4d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v1B80pD3AFd*dc*dsc*dp*ic*isc*ip*in* alias: usb:v1B80pD3B0d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v1B80pD39Dd*dc*dsc*dp*ic*isc*ip*in* alias: usb:v1B80pD395d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v0458p707Fd*dc*dsc*dp*ic*isc*ip*in* alias: usb:v1F4DpA803d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v0413p6A03d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v1B80pD394d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v185Bp0650d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v185Bp0620d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v1D19p1104d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v1B80pD393d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v1B80pD3A8d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v0CCDp00D7d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v1D19p1102d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v0CCDp00D3d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v0413p6F12d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v0413p6F0Fd*dc*dsc*dp*ic*isc*ip*in* alias: usb:v0413p6680d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v1D19p1101d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v1F4DpC803d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v0CCDp00B4d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v0CCDp00E0d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v0CCDp00B3d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v1F4DpB803d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v0CCDp00A9d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v0BDAp2838d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v0BDAp2832d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v14AAp0161d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v14AAp0160d*dc*dsc*dp*ic*isc*ip*in* alias: usb:v0BDAp2831d*dc*dsc*dp*ic*isc*ip*in* depends: dvb_usb_v2 intree: Y name: dvb_usb_rtl28xxu vermagic: 4.14.94-odroidxu4 SMP preempt mod_unload ARMv7 thumb2 p2v8 parm: disable_rc:disable RTL2832U remote controller (int) parm: adapter_nr:DVB adapter numbers (array of short)
It's just the stock kernel and rtl modules, which have found their way to mainline kernel long ago.
/HXZ
Updated by da h4xX0rz1sT over 5 years ago
saen acro wrote:
Guess it mean in kernel itself
No, it's not a monolithic kernel, it has external modules that it loads.
filename: /lib/modules/4.14.94-odroidxu4/kernel/drivers/media/usb/dvb-usb-v2/dvb-usb-rtl28xxu.ko
"intree" means it comes from the mainline kernel tree, and it's not an out-of-tree module just compiled against that kernel.
/HXZ