Problems with BBC HD channels (Craigkelly)

ejstubbs

Member
We've been experiencing a problem with recordings from BBC HD channels suffering from picture freeze/skipping accompanied by audio drop-out for some time now. For a while it was a reasonably rare, brief and tolerable annoyance but recently it's become a lot worse. Poldark recorded last Sunday was almost unwatchable (because of the recording breaking up, not the quality of the programme itself!) and we had to resort to watching it on iPlayer via our NowTV box.

The problem only seems to occur on programmes recorded during the evening. We've experienced it on BBC One Scotland HD, BBC Two HD and BBC Four HD ie two different mutiplexes (BBC B and Com 7 HD). We've not noticed it on any non-BBC HD channels such as STV HD, Channel 4 HD or Channel 5 HD, or on any SD channels. I've had a look at the signal strength and quality on the HD muxes and BBC B looks rock solid, although quality on Com 7 HD does bounce up and down a bit.

The thing is, if it was a signal problem then you'd expect it to affect other channels on the same muxes, which doesn't seem to be the case. Experience to date really does indicate that it's only the BBC HD channels that are affected.

I have begun to wonder whether it might be something to do with dual recording, which we use quite a lot in the evening. But then you'd expect it to affect whichever other channel was being recorded at the same time. The only way this would make sense to me would be if the Humax had a preferential choice for a particular tuner for certain channels, and the one it likes to use for the BBC HD channels is starting to fail. But that's just a wild hypothesis with no basis in anything approaching real knowledge.

Anyone have any ideas where to go next with fault-finding and fixing this?

I do have the custom firmware and the web interface installed, so if there are any useful diagnostics I could run or logging I could enable using those tools then I'm happy to try that.
 

Trev

The Dumb One
Is it only recordings that are iffy? If you watch the live programme via the box is that OK. If you watch the programme via your TV is that OK?
 

Mike0001

Well-Known Member
I don't think this is related, but on a recent holiday in North Norfolk, we had endless trouble with recording BBC HD channels on a Panasonic PVR. In the end I did a complete retune and found that the only way to get a decent signal was having most channels on one transmitter and the rest on another. The BBC HD signal strength on one transmitter was all over the shop, even though everything else was fine.
 
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ejstubbs

Member
Is it only recordings that are iffy? If you watch the live programme via the box is that OK. If you watch the programme via your TV is that OK?

The TV doesn't have an HD tuner. We haven't noticed the problem watching live TV through the Humax. But then, we don't tend to watch programmes live simultaneously with them being recorded.

It's odd. All but one of the recordings of Springwatch from last week (we were on holiday abroad) were rock solid. The one that did glitch was only minor. But Poldark recorded on Sunday was awful.

One thing I haven't tried (because it would probably drive SWMBO up the wall) is rewinding over the part that glitched to see if it does it on a second play. Think I might have to do that. If it does do it every time then that suggests a problem with the recording, either in reception or in saving to disc. If it doesn't then...dunno!?
 

Black Hole

May contain traces of nut
WebIF >> Diagnostics >> Disk Diagnostics produces the SMART diagnostic data collected by the HDD itself while on line. The same is available by entering "diskattr" in place of "general" near the top of the Diagnostics page and clicking Run Diagnostic - the output is then amenable to copying and pasting into a code box in a forum post.

Although this is useful for inspection, there is no harm in going straight to the command line and running the fixdisk utility from the maintenance mode Telnet menu. If you have the webshell package installed, this can be done from a browser without even bothering with a Telnet client: WebIF >> Diagnostics >> Command Line.

More info:
https://wiki.hummy.tv/wiki/Maintenance_Mode_Disk_Check
Quick Guide to Disk Recovery (click)
 
Last edited:
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ejstubbs

Member

Thanks, Ezra.

I ran it using the diskattr command as suggsted by Black Hole. Output follows:

Code:
>>> Beginning diagnostic diskattr

Running: diskattr
smartctl 6.4 2015-06-04 r4109 [7405b0-smp-linux-2.6.18-7.1] (local build)
Copyright (C) 2002-15, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:     Seagate Pipeline HD 5900.2
Device Model:     ST3500312CS
Serial Number:    6VV3ATMB
LU WWN Device Id: 5 000c50 027e131f5
Firmware Version: SC13
User Capacity:    500,107,862,016 bytes [500 GB]
Sector Size:      512 bytes logical/physical
Rotation Rate:    5900 rpm
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ATA8-ACS T13/1699-D revision 4
SATA Version is:  SATA 2.6, 3.0 Gb/s (current: 3.0 Gb/s)
Local Time is:    Thu Jun 15 10:34:58 2017 BST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART Attributes Data Structure revision number: 10
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x000f   118   099   006    Pre-fail  Always       -       194112589
  3 Spin_Up_Time            0x0003   097   097   000    Pre-fail  Always       -       0
  4 Start_Stop_Count        0x0032   083   083   020    Old_age   Always       -       17734
  5 Reallocated_Sector_Ct   0x0033   100   100   036    Pre-fail  Always       -       0
  7 Seek_Error_Rate         0x000f   086   060   030    Pre-fail  Always       -       419982026
  9 Power_On_Hours          0x0032   084   084   000    Old_age   Always       -       14844
 10 Spin_Retry_Count        0x0013   100   100   097    Pre-fail  Always       -       0
 12 Power_Cycle_Count       0x0032   092   092   020    Old_age   Always       -       8867
184 End-to-End_Error        0x0032   100   100   099    Old_age   Always       -       0
187 Reported_Uncorrect      0x0032   100   100   000    Old_age   Always       -       0
188 Command_Timeout         0x0032   100   100   000    Old_age   Always       -       0
189 High_Fly_Writes         0x003a   095   095   000    Old_age   Always       -       5
190 Airflow_Temperature_Cel 0x0022   047   039   045    Old_age   Always   In_the_past 53 (Min/Max 26/56 #3729)
194 Temperature_Celsius     0x0022   053   061   000    Old_age   Always       -       53 (0 16 0 0 0)
195 Hardware_ECC_Recovered  0x001a   042   024   000    Old_age   Always       -       194112589
197 Current_Pending_Sector  0x0012   100   100   000    Old_age   Always       -       0
198 Offline_Uncorrectable   0x0010   100   100   000    Old_age   Offline      -       0
199 UDMA_CRC_Error_Count    0x003e   200   200   000    Old_age   Always       -       0



>>> Ending diagnostic diskattr

I am about to have a go at launching fixdisk.
 
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ejstubbs

Member
Just for completeness, here is the output from fixdisk:

Code:
      /---------------------------------------------\                                                                                                                                         
      |  M A I N T E N A N C E   M O D E   M E N U  |                                                                                                                                         
      \---------------------------------------------/                                                                                                                                         
                                                                                                                                                                                              
  [ Humax HDR-Fox T2 (humax) 1.03.12/3.13 ]                                                                                                                                                   
                                                                                                                                                                                              
 fixdisk - Check and repair hard disk.                                                                                                                                                       
   short - Run short hard-disk self test.                                                                                                                                                     
    long - Run long hard-disk self test.                                                                                                                                                     
   check - Check self-test progress.                                                                                                                                                         
    gptf - Re-format disk using GPT scheme.                                                                                                                                                   
     epg - Clear persistent EPG data.                                                                                                                                                         
    dlna - Reset DLNA server database.                                                                                                                                                       
       x - Leave maintenance mode (Humax will restart).                                                                                                                                       
    diag - Run a diagnostic.                                                                                                                                                                 
     cli - System command line (advanced users).                                                                                                                                             
                                                                                                                                                                                              
Please select option: fixdisk                                                                                                                                                                 
Any additional options (-h for list or press return for none): -d -l -w                                                                                                                       
Are you sure you wish to run the hard disk checker (-d -l -w)? [Y/N] y                                                                                                                       
Running /bin/fix-disk                                                                                                                                                                         
PART: [3 1 2]                                                                                                                                                                                 
FSCKOPTS: []                                                                                                                                                                                 
                                                                                                                                                                                              
Checking disk sdb (512 byte sectors)                                                                                                                                                         
                                                                                                                                                                                              
Unmounted /dev/sdb1                                                                                                                                                                           
Unmounted /dev/sdb2                                                                                                                                                                           
Unmounted /dev/sdb3                                                                                                                                                                           
                                                                                                                                                                                              
                                                                                                                                                                                              
Running long disk self test                                                                                                                                                                   

No pending sector errors found                                                                                 
                                                                                                                
Checking partition tables...                                                                                   
                                                                                                                
MBR Status: MBR only                                                                                           
GPT Status: not present                                                                                         
                                                                                                                
Using superblock 0 on sdb1                                                                                     
Using superblock 0 on sdb2                                                                                     
Using superblock 0 on sdb3                                                                                     
                                                                                                                
                                                                                                                
Thu Jun 15 12:24:49 BST 2017: Checking partition /dev/sdb3...                                                   
e2fsck 1.42.13 (17-May-2015)                                                                                   
Pass 1: Checking inodes, blocks, and sizes                                                                     
Pass 1: Memory used: 240k/0k (157k/84k), time:  8.85/ 3.41/ 2.56                                               
Pass 1: I/O read: 164MB, write: 0MB, rate: 18.53MB/s                                                           
Pass 2: Checking directory structure                                                                           
Pass 2: Memory used: 340k/0k (259k/82k), time:  0.02/ 0.00/ 0.00                                               
Pass 2: I/O read: 1MB, write: 0MB, rate: 47.42MB/s                                                             
Pass 3: Checking directory connectivity                                                                         
Peak memory: Memory used: 340k/0k (259k/82k), time:  9.38/ 3.67/ 2.61                                           
Pass 3A: Memory used: 340k/0k (259k/82k), time:  0.00/ 0.00/ 0.00                                               
Pass 3A: I/O read: 0MB, write: 0MB, rate: 0.00MB/s                                                             
Pass 3: Memory used: 340k/0k (259k/82k), time:  0.00/ 0.00/ 0.00                                               
Pass 3: I/O read: 0MB, write: 0MB, rate: 0.00MB/s                                                               
Pass 4: Checking reference counts                                                                               
Pass 4: Memory used: 340k/0k (53k/288k), time:  1.22/ 1.19/ 0.01                                               
Pass 4: I/O read: 0MB, write: 0MB, rate: 0.00MB/s                                                               
Pass 5: Checking group summary information                                                                     
Pass 5: Memory used: 340k/0k (53k/288k), time:  3.11/ 2.41/ 0.04                                               
Pass 5: I/O read: 1MB, write: 0MB, rate: 0.32MB/s                                                               
                                                                                                                
          17 inodes used (0.00%, out of 655776)                                                                 
           1 non-contiguous file (5.9%)                                                                         
           0 non-contiguous directories (0.0%)                                                                 
             # of inodes with ind/dind/tind blocks: 3/2/0                                                       
      311775 blocks used (11.89%, out of 2622611)                                                               
           0 bad blocks                                                                                         
           1 large file                                                                                         
                                                                                                                
           6 regular files                                                                                     
           2 directories
           0 character device files                                                                             
           0 block device files                                                                                 
           0 fifos                                                                                             
           0 links                                                                                             
           0 symbolic links (0 fast symbolic links)                                                             
           0 sockets                                                                                           
------------                                                                                                   
           8 files                                                                                             
Memory used: 340k/0k (53k/288k), time: 13.73/ 7.28/ 2.66                                                       
I/O read: 166MB, write: 1MB, rate: 12.09MB/s                                                                   
Thu Jun 15 12:25:03 BST 2017                                                                                   
                                                                                                                
Thu Jun 15 12:25:03 BST 2017: Checking partition /dev/sdb1...                                                   
e2fsck 1.42.13 (17-May-2015)                                                                                   
Pass 1: Checking inodes, blocks, and sizes                                                                     
Pass 1: Memory used: 140k/0k (62k/79k), time:  0.77/ 0.23/ 0.41                                               
Pass 1: I/O read: 17MB, write: 0MB, rate: 22.15MB/s                                                             
Pass 2: Checking directory structure                                                                           
Pass 2: Memory used: 140k/0k (72k/69k), time:  0.01/ 0.00/ 0.00                                                 
Pass 2: I/O read: 1MB, write: 0MB, rate: 75.92MB/s                                                             
Pass 3: Checking directory connectivity                                                                         
Peak memory: Memory used: 140k/0k (72k/69k), time:  0.89/ 0.26/ 0.42                                           
Pass 3A: Memory used: 140k/0k (72k/69k), time:  0.00/ 0.00/ 0.00                                               
Pass 3A: I/O read: 0MB, write: 0MB, rate: 0.00MB/s                                                             
Pass 3: Memory used: 140k/0k (71k/70k), time:  0.00/ 0.00/ 0.00                                                 
Pass 3: I/O read: 0MB, write: 0MB, rate: 0.00MB/s                                                               
Pass 4: Checking reference counts                                                                               
Pass 4: Memory used: 140k/0k (50k/91k), time:  0.11/ 0.11/ 0.00                                               
Pass 4: I/O read: 0MB, write: 0MB, rate: 0.00MB/s                                                               
Pass 5: Checking group summary information                                                                     
Pass 5: Memory used: 140k/0k (50k/91k), time:  0.36/ 0.29/ 0.00                                               
Pass 5: I/O read: 1MB, write: 0MB, rate: 2.75MB/s                                                               
                                                                                                                
          14 inodes used (0.02%, out of 65808)                                                                 
           0 non-contiguous files (0.0%)                                                                       
           0 non-contiguous directories (0.0%)                                                                 
             # of inodes with ind/dind/tind blocks: 2/1/0                                                       
       15356 blocks used (5.84%, out of 263064)                                                                 
           0 bad blocks                                                                                         
           1 large file                                                                                         
                                                                                                                
           2 regular files                                                                                     
           3 directories                                                                                       
           0 character device files                                                                             
           0 block device files                                                                                 
           0 fifos                                                                                             
           0 links                                                                                             
           0 symbolic links (0 fast symbolic links)                                                             
           0 sockets                                                                                           
------------                                                                                                   
           5 files                                                                                             
Memory used: 140k/0k (50k/91k), time:  1.37/ 0.66/ 0.43                                                         
I/O read: 17MB, write: 1MB, rate: 12.38MB/s                                                                     
Thu Jun 15 12:25:04 BST 2017                                                                                   
                                                                                                                
Creating swap file...                                                                                           
Setting up swapspace version 1, size = 1073737728 bytes                                                         
UUID=1370915b-c7b8-4664-b2f2-0f7f0dad70c6                                                                       
                                                                                                                
Thu Jun 15 12:25:28 BST 2017: Checking partition /dev/sdb2...                                                   
e2fsck 1.42.13 (17-May-2015)                                                                                   
Pass 1: Checking inodes, blocks, and sizes                                                                     
Pass 1: Memory used: 820k/4672k (524k/297k), time: 1421.55/800.10/83.67                                       
Pass 1: I/O read: 7562MB, write: 0MB, rate: 5.32MB/s                                                           
Pass 2: Checking directory structure                                                                           
Pass 2: Memory used: 820k/9344k (512k/309k), time:  2.30/ 0.57/ 0.13                                           
Pass 2: I/O read: 5MB, write: 0MB, rate: 2.18MB/s                                                               
Pass 3: Checking directory connectivity                                                                         
Peak memory: Memory used: 820k/9344k (512k/309k), time: 1442.33/818.53/83.86                                   
Pass 3A: Memory used: 820k/9344k (525k/296k), time:  0.00/ 0.00/ 0.00                                           
Pass 3A: I/O read: 0MB, write: 0MB, rate: 0.00MB/s                                                             
Pass 3: Memory used: 820k/9344k (507k/314k), time:  0.06/ 0.03/ 0.00                                           
Pass 3: I/O read: 1MB, write: 0MB, rate: 16.95MB/s                                                             
Pass 4: Checking reference counts                                                                               
Pass 4: Memory used: 820k/0k (463k/358k), time: 50.04/49.36/ 0.05                                             
Pass 4: I/O read: 0MB, write: 0MB, rate: 0.00MB/s                                                               
Pass 5: Checking group summary information                                                                     
Pass 5: Memory used: 820k/0k (450k/371k), time: 131.67/100.48/ 1.15                                           
Pass 5: I/O read: 29MB, write: 0MB, rate: 0.22MB/s                                                             
                                                                                                                
        7803 inodes used (0.03%, out of 29860704)                                                               
         406 non-contiguous files (5.2%)
          12 non-contiguous directories (0.2%)                                                                 
             # of inodes with ind/dind/tind blocks: 554/246/2                                                   
    71429433 blocks used (59.92%, out of 119209984)                                                             
           0 bad blocks                                                                                         
          26 large files                                                                                       
                                                                                                                
        6357 regular files                                                                                     
         386 directories                                                                                       
           0 character device files                                                                             
           0 block device files                                                                                 
           0 fifos                                                                                             
           0 links                                                                                             
        1051 symbolic links (1051 fast symbolic links)                                                         
           0 sockets                                                                                           
------------                                                                                                   
        7794 files
Memory used: 820k/0k (450k/371k), time: 1624.24/968.41/85.07                                                   
I/O read: 7596MB, write: 1MB, rate: 4.68MB/s                                                                   
Thu Jun 15 12:52:32 BST 2017                                                                                   
Removing extra swap space.                                                                                     
                                                                                                                
Finished                                                                                                       
                                                                                                                
--- Press return to exit ---                                                                                     
fix-disk: session terminated with exit status 0
 
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ejstubbs

Member
Ok, here it is:


Is this OK? We certainly weren't watching anything on COM5 at the time. I'm a bit confused why nothing is showing against any of the other muxes.
 

prpr

Well-Known Member
Is this OK?
It shows you have the correct RF channels tuned.
I'm a bit confused why nothing is showing against any of the other muxes.
Because you have done a manual tune on COM5 at some point. It's another stupid Humax bug which blows away the data for the other muxes (you could work around it with tunefix).
 
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ejstubbs

Member
Er, OK. AFAICR I have tunefix installed, but I'm not sure how it would help in this case.

Anyway, these results suggest that there's nothing obviously wrong on the box itself. Which actually isn't bad considering it's coming up to seven years old.

Looks like I'll have to do so more investigation for possible signal issues. And next time it happens I will make sure to rewind and replay the glitchy section to see if the problem is embedded in the recording, or the result of a playback artefact.
 

Black Hole

May contain traces of nut
Er, OK. AFAICR I have tunefix installed, but I'm not sure how it would help in this case.
It can't help with your problem, but the point is that an auto-tune collects the stats for all the tuned multiplexes (as shown in post 16) whereas a manual tune wipes all the stats and updates only the stats for the mux you are tuning (Humax bug). The stats are only valid at the time of tuning, they do not update with changing conditions.

In most cases tunefix makes manual tuning unnecessary because, once configured to your liking, you can just run an auto-tune, then next time you reboot tunefix sorts everything out for you according to your preferences (eg: remove all channels named "Adult*", put BBC ONE HD on LCN 1, etc etc). Note that some options are not currently supported by the GUI config editor and have to be patched in by hand.

The only situation I can think of which tunefix can't hack is if the user receives signals from more than one transmitter in the same local region and for some reason doesn't want the transmitter the auto-tune defaults to (only one version of, say, BBC ONE West is kept by the auto-tuning process, so if the box decides to keep the one from Transmitter A but you want the one from Transmitter B, you will have to manually tune the muxes from Transmitter B). However, even in that case, you can still run a selective tune and then reboot to let tunefix do all the other stuff.

I can even use auto-tuning and tunefix to sort out my multi-region setup, as documented in the relevant topic:
https://hummy.tv/forum/threads/tune...tion-and-maintenance.6639/page-10#post-103846
 

prpr

Well-Known Member
Er, OK. AFAICR I have tunefix installed, but I'm not sure how it would help in this case.
The data that the Humax software clears out in a Manual tune gets put back by tunefix, as it takes a copy beforehand. Obviously the data has to be there to start with, which it isn't in your case. The only solution to that is to do an Auto-tune. But any subsequent Manual tunes won't then cause the data to be lost.
 
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