FFmpeg/vaapi Sample Player (ffvademo)
Copyright (C) 2014 Intel Corporation Author: Gwenole Beauchesne [email protected]
The FFmpeg/vaapi Sample Player (ffvademo) and its associated helper library are available available under the terms of the GNU Lesser General Public License v2.1+
This project consists in a simple FFmpeg/vaapi based video player, and an associated helper library, that demonstrate how to use FFmpeg with Video Acceleration (VA) APIs.
- FFmpeg decoder with VA-API support
- Native X11 renderer through vaPutSurface()
- EGL renderer showing off VA/EGL interop capabilities
Non-goals
- A full-blown player supporting every possible codec
- A player that supports audio decoding
- A player that supports software decoding
Software requirements
- VA-API (>= 0.36.0 for VA/EGL interop)
- FFmpeg (>= 2.1)
-
Play an H.264 video with an MP4 container $ ffvademo /path/to/video.mp4
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Play a VC-1 video while converting the output to I420 format $ ffvademo -f yuv420p /path/to/video.wmv
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Play an H.264 video while rendering with EGL/GLESv2 $ ffvademo -r egl -f argb /path/to/video.mp4
- sudo apt install libva-dev libegl-dev，安装编译依赖。
- 使用cmake . 在本地生成Makefile
- make编译，得到ffvademo可执行程序。
- 执行./ffvademo a.mp4 -r egl，使用egl渲染视频。
- 假如没有找到 vaapi 后端库，试试 export LIBVA_DRIVER_NAME=jmgpu，然后再运行ffvademo程序。
- ffmpeg调用vaapi解码，得到一个AVFrame
- 取AVFrame的data[3]，得到一个VASurfaceID
- 通过vaDeriveImage将VASurfaceID转换成一个VAImage
- 通过avAcquireBufferHandle将AVImage的信息提取出来，得到VABufferInfo
- 通过eglCreateImageKHR，将VABufferInfo的内容填充到attributes中，根据这个信息创建衣蛾EGLImageKHR
- 使用eglImageTargetTexture2DOES，将EGLImageKHR附加到opengl的texture上。
- 之后就是正常的opengl纹理操作。
以上就是vaapi解码的数据，是如何与opengl结合，显示在界面上的。其他的细节这里忽略。在贴纹理显示视频之前，需要调用 vaSyncSurface，来保证解码已经处理完，否则可能会出现绿色的墙砖一样的问题。