It's not ergonomic for the calling code to pass in an array of references. Just take ownership of that array, as it's not going to be used again when the calling code succeeds in creating the wrapper. BUG=b:214478588 TEST="cargo build --features=video-decoder,vaapi" successfully builds the libva crate Change-Id: I97d91f9f996c298450e65c21c126a9739ec4615f Reviewed-on: https://chromium-review.googlesource.com/c/crosvm/crosvm/+/3900314 Commit-Queue: Alexandre Courbot <acourbot@chromium.org> Reviewed-by: Alexandre Courbot <acourbot@chromium.org> Reviewed-by: Keiichi Watanabe <keiichiw@chromium.org> |
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.. | ||
src | ||
bindgen.sh | ||
build.rs | ||
Cargo.toml | ||
libva-wrapper.h | ||
README.md |
Libva Rust wrapper
Rust wrapper for libva. Provides safe libva abstractions for use within Rust code using its own bindgen-generated bindings.
This crate is used as part of the VirtIO Video VA-API backend. VA-API uses the GPU to perform the actual decoding/encoding of frames. In doing so, it frees the CPU for other uses and reduces power usage in the system. Hardware accelerated media workflows also tend to be faster than their software counterparts.
Note: This create requires the native libva library at link time. It also requires a VA-API driver to be installed on the system. The VA-API driver to use depends on the underlying hardware, e.g.: the implementation for Intel hardware is in intel-media-driver, whereas AMD hardware will depend on Mesa.
An easy way to see whether everything is in order is to run the vainfo
utility. This is usually
packaged with libva-utils
or as a standalone package in some distributions. vainfo
will print
the VA-API version, the driver string, and a list of supported profiles and endpoints, i.e.:
vainfo: VA-API version: 1.13 (libva 2.13.0)
vainfo: Driver version: Intel iHD driver for Intel(R) Gen Graphics - 22.2.2 ()
vainfo: Supported profile and entrypoints
VAProfileNone : VAEntrypointVideoProc
VAProfileNone : VAEntrypointStats
VAProfileMPEG2Simple : VAEntrypointVLD
VAProfileMPEG2Simple : VAEntrypointEncSlice
VAProfileMPEG2Main : VAEntrypointVLD
VAProfileMPEG2Main : VAEntrypointEncSlice
VAProfileH264Main : VAEntrypointVLD
etc
For decoding, the desired profile must be supported under VAEntrypointVLD
. For example, in order
to decode VP8 media, this line must be present in the output of vainfo
:
VAProfileVP8Version0_3 : VAEntrypointVLD
Whereas to decode H264 Main profile media, this line must be present:
VAProfileH264Main : VAEntrypointVLD
For more information on VA-API and its usage within ChromeOS, see this guide.
For a brief introduction on how to use this crate, see the libva_utils_mpeg2vldemo
test under
src/lib.rs.