[mythtv-users] video playback routing

[Michael T. Dean]

On 03/19/2016 03:46 PM, Dan Littlejohn wrote:
> On Sat, Mar 19, 2016 at 1:26 PM, Michael T. Dean wrote:
>
>> On 03/18/2016 04:03 PM, Dan Littlejohn wrote:
>>
>>> Let me make another attempt to explain, I think I have a pretty standard
>>> setup
>>>
>>> host1 - backend master and frontend
>>> host2 - backend slave and frontend
>>>
>>> playing dvd iso on host1 frontend and all boxes have the same nfs paths.
>>> All boxes use the same user.  Yes, the ISOs are stored in a local nfs
>>> directory /myth/video/.
>>>
>>> Looks like you are on to something with the file type, as ISOs look to be
>>> a key with the problem.  I checked the other video types and they play
>>> locally with no network traffic.  Only the ISOs do with the weird streaming
>>> from the slave.
>>>
>> Is it an encrypted ISO?
> Nope, they are not encrypted.

I still wouldn't be surprised if it's the code that was added to allow 
streaming of DVDs/ISOs for Video Library--meaning that it always 
streams.  If so, the code is broken in assuming that backend streaming 
is required for all ISOs and not even allowing the frontend to check to 
see if it has access before streaming. If that's the case, you are more 
than welcome to fix it.  It should work like playback of recordings and 
other videos--that the backend says where the file is located and the 
frontend checks in that location to see if it has local access and, if 
so, plays the file directly.

This specific code was committed under a bad commit message saying that 
it allows playback of
encrypted DVDs and ISOs from Storage Groups, when it actually simply 
allows streaming of DVDs and ISOs and has nothing to do with 
encryption***.  However, you can find the commit at:

https://github.com/MythTV/mythtv/commit/1ff446ad093064ff3

See also:

https://code.mythtv.org/trac/ticket/11602

Mike

*** MythTV cannot play back encrypted DVDs.  MythTV uses libdvdnav to 
play back unencrypted DVDs.  However, libdvdnav happens to check to see 
if the user has installed libdvdcss on his system and, if so, uses it to 
decrypt encrypted DVDs before MythTV ever sees any of the DVD data, so a 
user who installs libdvdcss on his system is setting up the system so 
that MythTV never actually sees any encrypted DVD. And MythTV worked 
exactly the same way before and after this commit--the only thing the 
commit allowed was streaming DVDs/ISOs rather than requiring direct file 
system access to play them.