There is no fixed limitation for the number of devices on the
decklink API side according to BlackMagic. Many PC motherboards
are able support 6 decklink cards each with up to 8 inputs so
a limit of 16 might well be too low.
https://bugzilla.gnome.org/show_bug.cgi?id=777239
The Decklink and GstAudioBaseSink APIs don't fit very well together,
which causes various problems due to inaccuracies in the clock
calculations and the actual ringbuffer and GStreamer's copy getting of
sync.
Problems are audio drop-outs and A/V sync getting wrong after
pausing/seeking.
https://bugzilla.gnome.org/show_bug.cgi?id=790114
The buffer itself is 128 bytes into the allocated memory area, to be
able to store the size and other metadata before it. Freeing the buffer
directly will make malloc moderately unhappy.
HRESULT is unsigned long on Windows, but the Decklink headers define
it to 'int' on Linux. Confusingly, the defines that talk about the
possible return values for it use long constants. The easy fix would
be to change the linux/LinuxCOM.h header, but that's copied from the
decklink SDK.
Change the logging to always upcast to unsigned long while printing
HRESULT for consistency across platforms.
The default memory allocator of the decklink library allocates
a fixed pool of buffers, and the number of buffers is unknown.
This makes it impossible do useful queuing downstream. The new
memory allocator can create an unlimited number of buffers,
giving all queuing features one would expect from a live source.
https://bugzilla.gnome.org/show_bug.cgi?id=782556
The audio packet times can be completely unrelated to the video stream
time, depending on the card. While this looks like a bug in the driver,
just always using the video stream time (which is correct) works as a
workaround for now.
This reverts commit 845832263b.
The commit broke cross-mingw CI:
https://ci.gstreamer.net/job/GStreamer-master/8659/console
It seems that cross-mingw on Autotools and native-mingw on Meson
disagree about the size of HRESULT. Revert for now till I can
investigate the Meson side of things some more.
MinGW does not provide comsupp.lib, so there's no implementation of
_com_util::ConvertBSTRToString. Use a fallback implementation that
uses wcstombs() instead.
On MinGW we also truncate the name to 100 chars which should be fine.
gstdecklink.cpp:821:11: warning: variable 'dtc' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
if (m_input->videosrc) {
^~~~~~~~~~~~~~~~~
gstdecklink.cpp:837:41: note: uninitialized use occurs here
stream_time, stream_duration, dtc, no_signal);
^~~
gstdecklink.cpp:821:7: note: remove the 'if' if its condition is always true
if (m_input->videosrc) {
^~~~~~~~~~~~~~~~~~~~~~~
gstdecklink.cpp:810:29: note: initialize the variable 'dtc' to silence this warning
IDeckLinkTimecode *dtc;
^
= NULL
gstdecklink.cpp: In member function ‘virtual HRESULT GStreamerDecklinkInputCallback::VideoInputFrameArrived(IDeckLinkVideoInputFrame*, IDeckLinkAudioInputPacket*)’:
gstdecklink.cpp:766:34: error: ‘base_time’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
capture_time -= base_time;
^
First of all, all the HD and UHD modes should be top-field-first, as
also returned by the Decklink mode iterator API.
Then we should include the caps field "field-order" in the caps of the
source (not the sink due to negotiation problems with optional fields).
And finally we should set the TFF flag on interlaced buffers that are
top-field-first.
The hardware timestamps have no relation to when frames were produced,
only when frames arrived somewhere in the hardware. Especially there is
no guarantee that audio and video will have the same hardware timestamps
although they belong together, and even more important: the rate with
which the hardware timestamps increase is completely unrelated to the
rate with which the frames are captured!
As such we can as well use the pipeline clock directly and stop doing
complicated calculations. Also as a side effect this allows now running
without any pipeline clock, by directly making use of the stream times
as reported by the driver.
https://bugzilla.gnome.org/show_bug.cgi?id=774850
When the mode of decklinkvideosink is set to "auto", the sink claims to
support the full set of caps that it can support for all modes. Then, every
time new caps are set, the sink will automatically find the correct mode for
these caps and set it.
Caveat: We have no way to know whether a specific mode will actually work for
your hardware. Therefore, if you try sending 4K video to a 1080 screen, it
will silently fail, we have no way to know that in advance. Manually setting
that mode at least gave the user a way to double-check what they are doing.
https://bugzilla.gnome.org/show_bug.cgi?id=759600
Otherwise we're going to return times starting at 0 again after shutting down
an element for a specific input/output and then using it again later.
https://bugzilla.gnome.org/show_bug.cgi?id=755426
gstdecklink.cpp: In member function 'virtual HRESULT GStreamerDecklinkInputCallback::VideoInputFrameArrived(IDeckLinkVideoInputFrame*, IDeckLinkAudioInputPacket*)':
gstdecklink.cpp:498:22: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
if (capture_time > m_input->clock_start_time)
^
gstdecklink.cpp:503:22: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
if (capture_time > m_input->clock_offset)
^
