[OpenIndiana-discuss] Comments, please! problem with ffmpeg that seems to be a problem with OI at driver or basic library level

[Hans J. Albertsson]

I have tried converting to different formats, and that doesn't affect 
the bug.

I cannot change the input stream, that format is a given.


On 2013-05-15 17:37, Colin Ellis wrote:
> I'd suggest trying ffmpeg out with different encodings first to see if it's
> stream-specific.  It might actually be libavcodec giving you the hang.
> I've seen endless loop bugs previously while transcoding audio.
>
>
> On Wed, May 15, 2013 at 8:52 AM, Hans J. Albertsson <
> hans.j.albertsson at branneriet.se> wrote:
>
>> I just discovered that with most Ubuntu versions and recent ffmpegs, the
>> same hang happens there.
>>
>> So it isn't just OI.
>>
>> Good. Or bad.. Or something. I will look into it, trussing and whatever. I
>> mean my ffmpeg is locally compiled and I have the source code for reference.
>>
>> On 2013-05-15 16:05, Bob Friesenhahn wrote:
>>
>>> On Wed, 15 May 2013, Hans J. Albertsson wrote:
>>>
>>>   I regularly download ( quite legally, I'm told ) HLS streams from
>>>> svtplay.se using ffmpeg and a stream URL obtained by scraping the
>>>> svtplay.se/<show-link> page.
>>>>
>>>> This works very well in Ubuntu and Windows on a separate PC.
>>>>
>>>> Under OI and even in W XP inside a VirtualBox VM it hangs, seemingly at
>>>> random positions in the stream. The ffmpeg process is totally inert upon
>>>> hanging, and one must kill it by two consecutive ^C. It doesn't respond to
>>>> the on the fly command language at all.
>>>>
>>>> The hang is in pollsys, as demonstrated by the following truss -f output
>>>> excerpt from the hanging ffmpeg process.
>>>>
>>>> 29961:    pollsys(0x08046768, 1, 0x08046718, 0x00000000)    = 0
>>>> 29961:    pollsys(0x08046768, 1, 0x08046718, 0x00000000)    = 0
>>>> 29961:    pollsys(0x08046768, 1, 0x08046718, 0x00000000)    = 0
>>>> 29961:    pollsys(0x08046768, 1, 0x08046718, 0x00000000)    = 0
>>>> 29961:    pollsys(0x08046768, 1, 0x08046718, 0x00000000)    = 0
>>>> 29961:    pollsys(0x08046768, 1, 0x08046718, 0x00000000)    = 0
>>>> 29961:    pollsys(0x08046768, 1, 0x08046718, 0x00000000)    = 0
>>>> 29961:    pollsys(0x08046768, 1, 0x08046718, 0x00000000)    = 0
>>>>
>>>>
>>>> I guess that the fact it happens in the W XP in vbox the same as in OI
>>>> itself indicates the problem somehow involves code residing under the Vbox
>>>> VM, even, and that it's some sort of incompatibility that only will
>>>> actually have an effect under some sort of race or race-like condition.
>>>>
>>>> I'd appreciate any insight any of you could offer into what this entails
>>>>
>>> I see similar issues with the VLC player which decides that 'mplayer' is
>>> too slow and not able to keep up.  Without taking time to diagnose, my
>>> first guess would be a buffering issue which causes the hang.  The software
>>> is developed under Linux and may have certain buffering (e.g. pipe
>>> buffering) expectations. Confusion between the buffering and any locking
>>> (or even just the buffering) might cause a deadlock in the software.
>>>
>>> To diagnose, try using 'pstack' on the processes which are hanging and
>>> see where they are hung.
>>>
>>> Bob
>>>
>>
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