This "reuses" the flags introduced for the av_vdpau_bind_context() API
function, and makes them available to all hwaccels. This does not affect
the current vdpau API, as av_vdpau_bind_context() should obviously
override the AVCodecContext.hwaccel_flags flags for the sake of
compatibility.
Certain hardware decoding APIs are not guaranteed to be thread-safe, so
having the user access decoded hardware surfaces while the decoder is
running in another thread can cause failures (this is mainly known to
happen with DXVA2).
For such hwaccels, only allow the decoding thread to run while the user
is inside a lavc decode call (avcodec_send_packet/receive_frame).
This improves commit 59c7022740.
In ff_thread_report_progress(), the fast code path can load
progress[field] with the relaxed memory order, and the slow code path
can store progress[field] with the release memory order. These changes
are mainly intended to avoid confusion when one inspects the source code.
They are unlikely to have measurable performance improvement.
ff_thread_report_progress() and ff_thread_await_progress() form a pair.
ff_thread_await_progress() reads progress[field] with the acquire memory
order (in the fast code path). Therefore, one expects to see
ff_thread_report_progress() write progress[field] with the matching
release memory order.
In the fast code path in ff_thread_report_progress(), the atomic load of
progress[field] doesn't need the acquire memory order because the
calling thread is trying to make the data it just decoded visible to the
other threads, rather than trying to read the data decoded by other
threads.
In ff_thread_get_buffer(), initialize progress[0] and progress[1] using
atomic_init().
Signed-off-by: Wan-Teh Chang <wtc@google.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
The current code stores a pointer to the packet passed to the decoder,
which is then used during get_buffer() for timestamps and side data
passthrough. However, since this is a pointer to user data which we do
not own, storing it is potentially dangerous. It is also ill defined for
the new decoding API with split input/output.
Fix this problem by making an explicit internally owned copy of the
packet properties.
When decoding with threads enabled, the get_format callback will be
called with one of the per-thread codec contexts rather than with the
outer context. If a hwaccel is in use too, this will add a reference
to the hardware frames context on that codec context, which will then
propagate to all of the other per-thread contexts for decoding. Once
the decoder finishes, however, the per-thread contexts are not freed
normally, so these references leak.
The rationale is that coded_frame was only used to communicate key_frame,
pict_type and quality to the caller, as well as a few other random fields,
in a non predictable, let alone consistent way.
There was agreement that there was no use case for coded_frame, as it is
a full-sized AVFrame container used for just 2-3 int-sized properties,
which shouldn't even belong into the AVCodecContext in the first place.
The appropriate AVPacket flag can be used instead of key_frame, while
quality is exported with the new AVPacketSideData quality factor.
There is no replacement for the other fields as they were unreliable,
mishandled or just not used at all.
Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
When decoding, this field holds the inverse of the framerate that can be
written in the headers for some codecs. Using a field called 'time_base'
for this is very misleading, as there are no timestamps associated with
it. Furthermore, this field is used for a very different purpose during
encoding.
Add a new field, called 'framerate', to replace the use of time_base for
decoding.
The most interesting parts are initialization in ff_MPV_common_init() and
uninitialization in ff_MPV_common_end().
ff_mpeg_unref_picture and ff_thread_release_buffer have additional NULL
checks for Picture.f, because these functions can be called on
uninitialized or partially initialized Pictures.
NULL pointer checks are added to ff_thread_release_buffer() stub function.
Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
avcodec_flush_buffers() must release all internally held references
according to its documentation, for which all the threads need to be
flushed.
CC:libav-stable@libav.org
Bug-Id: vlc/9665
pthread_wait_cond can wake up unexpectedly (Wikipedia: Spurious_wakeup).
The FF_THREAD_SLICE thread mechanism could spontaneously execute
jobs or allow the caller of avctx->execute to return before all
jobs were complete.
Test both cases to ensure the wakeup is real.
Signed-off-by: Ben Jackson <ben@ben.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
Sometimes, if pthread_create() failed, then pthread_cond_wait() could
accidentally be called in the worker threads after the uninit function
had already called pthread_cond_broadcast(), leading to a deadlock.
Don't call pthread_cond_wait() if c->done is set.
Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>
Those were useful when avcodec_thread_init() was a public functions. It
was deprecated and removed some time ago, so those checks are not needed
anymore.
Intra codecs do not need an update_thread_context() function and never
call ff_thread_finish_setup(). They rely on ff_thread_get_buffer()
calling it. So call it even if the get_buffer2 function pointer is
avcodec_default_get_buffer2 and it has not been called before.
Allows use of AVHWAccel based decoders with frame based multithreading.
The decoders will be forced into an non-concurrent mode by delaying
ff_thread_finish_setup() calls after decoding of the current frame
is finished.
This wastes memory by unnecessarily using multiple threads and thus
copies of the decoder context but allows seamless switching between
hardware accelerated and frame threaded software decoding when the
hardware decoder does not support the stream.
Mark Thompson
Vittorio Giovara
wm4
Anton Khirnov
Wan-Teh Chang
Luca Barbato
Diego Biurrun
Ben Jackson
Derek Buitenhuis
Sean McGovern
Janne Grunau
Hendrik Leppkes
Mans Rullgard
Martin Storsjö