[mythtv-users] mac build

[James Linder]

> On 2 Feb 2021, at 10:57 pm, John Pilkington <johnpilk222 at gmail.com> wrote:
> 
> On 02/02/2021 13:52, Mark Kendall wrote:
>> On Tue, 2 Feb 2021 at 00:08, James Linder <jam at tigger.ws> wrote:
>>> 
>>> Looks like a good start point, say if you want more:
>>> 
>>> * thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x16c13e008)
>>>   * frame #0: 0x00000001044689a8 myth`AudioOutputGraph::GetImage(long long) const + 2008
>>> myth`AudioOutputGraph::GetImage:
>>> ->  0x1044689a8 <+2008>: movswl (%rax), %ecx
>>>     0x1044689ab <+2011>: movl   %ecx, -0x168(%rbp)
>>>     0x1044689b1 <+2017>: cmpl   $0x1, -0x154(%rbp)
>>>     0x1044689b8 <+2024>: jle    0x1044689d4               ; <+2052>
>>> 
>> If I were a betting man, I'd guess that:-
>> https://github.com/MythTV/mythtv/blob/fixes/31/mythtv/libs/libmyth/audio/audiooutputgraph.cpp#L287

Actually that makes sense

if *most* timestamps are valid and you choose those by chance then all is well
but if you skip to a bad one then tilt.I never get a crash on E or <space> only on skip
Also editing good streams (either fixed or good luck recording) then no problems

>> is the problem. e.g. the timestamps are bogus (due to the problematic
>> stream) and the error is not picked up and/or checked, we then convert
>> that timestamp to an offset into a buffer - and don't bounds check the
>> offset in:-
>> https://github.com/MythTV/mythtv/blob/fixes/31/mythtv/libs/libmyth/audio/audiooutputgraph.cpp#L123
>> However - I would expect the issue to be 100% repeatable if that were
>> the case...

As I said if you choose the same point then it is repeatable (no doubt) but for testing Johns builg I marked and cut at random :-)

>> James - when it doesn't crash - do you sometimes see garbage in the
>> audio graph or does it look 'normal'?

I'll pay attention and report back

Thanks Mark, just one niggling point why the mac frontend but never my linux front ends. For past ages I have done my HD cutlist on linux and have never had a crash (SuSE and ubuntu, only built from source) crash.
On my laptop (mac) I run an ubuntu VM just for editing! (ansible just works on ubuntu, but needs handholding on SuSE)

(A comment: To some extent I find ubuntu leading the charge in "You WILL do what WE think is best" eg mythtv user for mythtv, sillypasswords not mythtv for sql, you want gsudo? forget it! It's a bad idea and you dont need it.
at least SuSE have xdg_menu_su)


james