On 4/15/2017 9:32 PM, James Almer wrote:
On 4/15/2017 7:41 AM, Marton Balint wrote:
On Thu, 13 Apr 2017, Aaron Levinson wrote:
On 4/13/2017 3:40 PM, Marton Balint wrote:
On Thu, 13 Apr 2017, Aaron Levinson wrote:
On 4/13/2017 2:12 AM, Hendrik Leppkes wrote:
On Thu, Apr 13, 2017 at 10:36 AM, Aaron Levinson <alevi...@aracnet.com>
wrote:
Give it some time for the other changes to be reviewed by the people
that actually know decklink itself, you can include that in any new
versions of the patch then, no need to send one for that right now.
- Hendrik
Actually, the coding changes made to the decklink source files in this
patch have pretty much nothing to do with decklink itself, and anyone
with familiarity with semaphores and pthread could review those changes.
In fact, all I really did was use already existing approaches for
replacing a semaphore with the combination of a condition variable,
mutex, and counter, and there are plenty of examples of how to do this
on the Web.
Yeah, the changes look fine, please send an updated patch, I will apply
it after some final testing.
Thanks,
Marton
Here's a new version of the patch with the pthreads dependency replaced with
threads.
Thanks, applied.
Wouldn't it be simpler to add posix semaphore emulation to w32threads
and os2threads?
The former should be trivial, and probably even without the need to
use mutexes or conditional variables given there's CreateSemaphore
and ReleaseSemaphore for this purpose. Not sure about the latter.
I addressed this in one of the commit log messages:
-------------------------------------------------------------------------
-- libavdevice/decklink_enc.cpp:
a) Eliminated include of pthread.h and semaphore.h.
b) Replaced use of semaphore with the equivalent using a combination
of a mutex, condition variable, and a counter
(frames_buffer_available_spots). In theory, libavutil/thread.h and
the associated code could have been modified instead to add
cross-platform implementations of the sem_ functions, but an
inspection of the ffmpeg source base indicates that there are only
two cases in which semaphores are used (including this one that was
replaced), so it was deemed to not be worth the effort.
--------------------------------------------------------------------------
I considered this approach, but the thought of having to do this in
os2threads.h pretty much dissuaded me. I had thought that OS/2 was
pretty much dead, but it appears that I was wrong. There is a yearly
conference, and a new version of OS/2 will soon be released.
However, the two places in ffmpeg that the sem_ functions were/are used
are likely not relevant to OS/2 anyway:
-- DeckLink: Blackmagic only provides drivers/kernel modules for
Windows, Linux, and OS/X
-- avdevice/jack.c: This pertains to www.jackaudio.org, and at least
based on what I can see at https://github.com/jackaudio/jack2, there
doesn't appear to be any build configuration for OS/2. jack support
also apparently needs sem_timedwait().
As such, someone could likely get away with just implementing the sem_
functions in w32threads.h.
Aaron
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
