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25 lines
1.3 KiB
Markdown
25 lines
1.3 KiB
Markdown
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# FFmpeg wrapper
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This is a minimal FFmpeg 4.4 wrapper for use with the virtio-video device, allowing to run a virtual
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video device backed by software decoding or encoding. This is useful for development and testing in
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situations where no supported video acceleration is available on the host.
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Although several FFmpeg binding crates exist, most of them are not able to link against the system
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FFmpeg, and [the only one that does](https://crates.io/crates/ffmpeg-sys) is released under a
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software license that makes our lawyers nervous. Also they all run bindgen at build time, which is
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not possible to do under the Chrome OS build system and would require to patch the crate with fully
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generated bindings.
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So taking this in consideration, as well as the extra work that it is to depend on external Rust
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crates in Chrome OS, it is preferable to add our own simple bindings here that cover just the parts
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of FFmpeg that we need.
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This crate has minimal dependencies ; on the FFmpeg side, it just uses `libavcodec`, `libavutil` and
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`libswscale`.
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The bindings can be updated using the `bindgen.sh` script. A few elements that bindgen cannot
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generate because they are behind C macros are re-defined in `avutil.rs` and `error.rs`, as well as
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tests to ensure their correctness.
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And that's about it.
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