Lookahead requires examining frame data over a large number of frames,
so when pkv added the change to fully reset the encoder when the bitrate
changes, nvenc will invalidate all buffers and basically starts over
from a completely clean slate.
It's possible to make lookahead work when changing the bitrate, but due
to how lookahead seems to works internally in nvenc, it will cause
continually increasing latency every time the bitrate is updated, which
is unideal.
Additionally, when lookahead is enabled, deadlocks can occur when
changing the bitrate in a thread other than the graphics thread.
Currently we allow it to be reset outside of the graphics thread. From
limited investigating, it would appear this deadlock occurs because
nvenc is locking and releasing old textures.
So instead of dealing with all these potential issues, disable the
ability to adjust bitrate when the user has lookahead enabled on nvenc.
It's not really worth implementing dynamic bitrate support when
lookahead is enabled if the latency is just going to continually
increase for every bitrate adjustment anyway.
Code submissions have continually suffered from formatting
inconsistencies that constantly have to be addressed. Using
clang-format simplifies this by making code formatting more consistent,
and allows automation of the code formatting so that maintainers can
focus more on the code itself instead of code formatting.
The initial DTS for non-fractional framerates was being incorrectly
calculated. It assumed that the time base was in frames when it was
not.
Closesobsproject/obs-studio#1857
According to nvidia's documentation using b-frames as reference results in
a slight quality improvement with no/negligible performance impact and is
recommended to be enabled by default when using multiple b-frames.
Because the new NVENC implementation requires texture sharing, if the
user chooses to use a secondary GPU, fall back to the old implementation
instead.
Adds a texture-based NVENC implementation which passes OBS NV12 output
textures directly to NVENC without downloading them off of the GPU,
increasing NVENC performance by a significant margin.
If NV12 textures are unavailable or the new encoder fails to initialize
for whatever reason, it will fall back to the FFmpeg NVENC
implementation safely.
Richard Stanway
Richard Stanway
jp9000
pkv
Gol-D-Ace
Colin Edwards
derrod