[mythtv-users] Recent "pixelation" or "glitches" in recordings (HDHR related?)

[Mike Perkins]

On 24/04/13 23:59, Thomas Mashos wrote:
> On Wed, Apr 24, 2013 at 3:04 PM, Mike Perkins wrote:
>
>> Chunks of a file can vanish due to bit rot. A *single bit* on a sector can
>> die, meaning the whole file is unreadable (depending on which bit, of
>> course).
> worthless. When going into the frontend it isn't doing a complete scan of
> every file (would take way too long on multi-terabyte backends). It's
> probably just checking if each file exists. Further, even if it was doing a
> scan and could identify files that existed but were bad, it doesn't notify
> the user nor attempt to schedule a rebroadcast of it.

I wasn't talking about file content here and you know it. Lose a bit in a 
directory entry or an inode and parts (or all) of any file can go missing.

>> The drive in question might be on a slave tuner which is powered off.
> Almost worthless. The backend knows the slave backend isn't available, so
> should mark the recording as not available without needing to scan for it.
> This is slightly more complicated as you can have shared storage between
> backends, but this shouldn't really be an issue as 95+% of people use a
> single combined Backend/Frontend.

That's not the point. The point is that the master backend can't access the file 
so must mark it 'not available'. It can't do that until it knows which storage 
directory the file is in. As people move files between directories/hosts all the 
time (by recent posts, anyway) it can't know where a file is without searching 
every storage directory to locate it.
>
>> Users might not touch the files outside of mythtv but other software might
>> when it fails.
> I've never seen a single case where any of the MythTV devs were OK with any
> third party application touching the recordings directly, so why is it up
> to mythtv to verify that some third party app didn't screw with the
> recordings? If a user sets up something that screws with mythtv recordings,
> I think it is perfectly reasonable that mythtv would just throw an error
> when attempting to playback that recording.
>
I never mentioned 'third party' software, although that may also be at fault. No 
OS is perfect and there is always the possibility of bugs in drivers. That's why 
patches are issued, isn't it?

-- 

Mike Perkins