* commit '1818a640cfdccd52e97edf13564f45bc3d0d93eb':
build: Fix dependencies for alsa/jack/sndio support
Added explicit enable (which will be automatically added later on in
ee480790c) to actually fix this commit. Without the explicit enables,
alsa, jack and sndio gets disabled.
Also added jack, alsa and sndio to the have list so the HAVE_* are
populated to make (this fixes the SKIPHEADERS chunks).
Merged-by: Clément Bœsch <u@pkh.me>
Purpose: avdevice/decklink: Removed pthread dependency by replacing
semaphore used in code appropriately. Doing so makes it easier to
build ffmpeg using Visual C++ on Windows. This is a contination of
Kyle Schwarz's "avdevice/decklink: Remove pthread dependency" patch
that is available at https://patchwork.ffmpeg.org/patch/2654/ . This
patch wasn't accepted, and as far as I can tell, there was no
follow-up after it was rejected.
Notes: Used Visual Studio 2015 (with update 3) for this.
Comments:
-- configure: Eliminated pthreads dependency for decklink_indev_deps
and decklink_outdev_deps and replaced with threads dependency
-- libavdevice/decklink_common.cpp / .h:
a) Eliminated semaphore and replaced with a combination of a mutex,
condition variable, and a counter (frames_buffer_available_spots).
b) Removed include of pthread.h and semaphore.h and now using
libavutil/thread.h instead.
-- libavdevice/decklink_dec.cpp: Eliminated include of pthread.h and
semaphore.h.
-- 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.
Signed-off-by: Marton Balint <cus@passwd.hu>
* commit '2f806622e1270d3ed1d41a53049a19673dafbe70':
bktr: Use memset(0) instead of zero initialization for struct sigaction
Merged-by: Clément Bœsch <u@pkh.me>
The framework will allocate a buffer and copy the data to it,
that takes time. But it avoids constently creating and
destroyng the shared memory segment, and that saves more time.
On my setup,
from ~200 to ~300 FPS at full screen (1920×1200),
from ~1400 to ~3300 at smaller size (640×480),
similar to legacy x11grab and confirmed by others.
Plus, shared memory segments are a scarce resource,
allocating potentially many is a bad idea.
Note: if the application were to drop all references to the
buffer before the next call to av_read_frame(), then passing
the shared memory segment as a refcounted buffer would be
even more efficient, but it is hard to guarantee, and it does
not happen with the ffmpeg command-line tool. Using a small
number of preallocated buffers and resorting to a copy when
the pool is exhausted would be a solution to get the better
of both worlds.
sigaction is not defined in standards as a struct starting with another
struct. Some *BSD variants do however, resulting in a warning from the
zero initialization, which this change eliminates.
This partially reverts a92be9b856.
