image: create from Picture methods Move the Image constructors to methods of Picture<PictureSync>, since it is the only source for images. Split into two methods for construction instead of relying on a boolean to try and derive the image. The problem with the boolean was that there was no way to know whether the derive operation succeeded or not.
This crate provides lightweight and (hopefully) safe libva abstractions for use within Rust code with minimal dependencies. It is developed for use in ChromeOS, but has no ChromeOS specifics or dependencies and should thus be usable anywhere.
The first version was written by Daniel Almeida and hosted in the crosvm repository before being split out here.
The native libva library is required at link time, so make sure to have the libva-dev or equivalent package for your distribution installed. The VA-API driver corresponding to your hardware is also required: for Intel hardware it will be intel-media-driver, whereas AMD hardware relies on Mesa.
An easy way to see whether everything is in order is to run the vainfo utility packaged with libva-utils or as a standalone package in some distributions. vainfo will print the VA-API version, 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.
The name of this crate is cros-libva to highlight the fact that it originates from ChromeOS and it not an official bindings. For ease of use, it is recommended to rename it to just libva in your project by using the following line in your Cargo.toml:
libva = { package = "cros-libva", version = "0.0.1" }
For a brief introduction on how to use this crate, see the libva_utils_mpeg2vldemo test under src/lib.rs. You can also quickly test MPEG2 decoding by running it:
cargo test -- --ignored libva_utils_mpeg2vldemo