FFmpeg Examples using Software Filters

The examples/ffmpeg/filters/ folder contains different examples showing how to use FFmpeg combining both Xilinx accelerated functions and software filters. In all these examples, the Xilinx device is used to decode the input stream, the decoded frames are transfered back to the host using the xvbm_convert filter, one of more software filters are applied to the decoded frames and the filtered frames are transfered back to the Xilinx device for encoding.

For more details about implicit and explicit data transfers between FFmpeg and Xilinx devices, refer to the documentation about Moving Data through the Video Pipeline.

IMPORTANT: There are two scripts for each example: one for 8-bit streams and one for 10-bit streams. This is because FFmpeg SW filters do not handle pixel formats consistently. When working with 10-bit streams, it is often required to explicitly specify the pixel format for the filter to function correctly.


Environment Setup

  1. The Xilinx Video SDK examples can be found in the /opt/xilinx/examples/u30 folder of your system. If this folder is not present, first make sure your package management client points to the remote package repository for the Xilinx Video SDK. Then install the xilinx-alveo-u30-examples package:

    • Ubuntu

    sudo apt-get install xilinx-alveo-u30-example

    • RHEL and Amazon Linux 2

    sudo yum install xilinx-alveo-u30-example

  2. Configure the environment to use the Xilinx Video SDK:

    source /opt/xilinx/xcdr/setup.sh

Video Rotation

This example accepts an 8-bit or 10-bit, YUV420, pre-encoded h264 file and will send the rotated, encoded h.264 output to /tmp/xil_rotate_<N>.mp4 at a rate of 8Mbps.

Logo Overlay

This example accepts an 8-bit or 10-bit, YUV420, pre-encoded h264 file and an image file (“logo”). It will scale the logo to 500x100, place it 16 pixels right and 16 pixels down from the top-left corner of the output video file, which will be an encoded h.264 output saved to /tmp/xil_logo_overlay.mp4 at a rate of 8Mbps.

Crop and Zoom

This example accepts an 8-bit or 10-bit, YUV420, pre-encoded h264 file and will crop a 300x200 sized section of the original video. The section’s top left corner begins at 20 pixels to the right, and 10 pixels down from the top-left corner of the original video. The output video is encoded in 8Mbps, and is saved to /tmp/xil_crop_zoom.mp4

Video Composition

This example accepts 4 8-bit or 10-bit, YUV420, pre-encoded h264 files of equal dimensions, and will create an output 2x2 composite video which will be an encoded h.264 output saved to /tmp/xil_2x2_composite.mp4 at a rate of 8Mbps. The output resolution will be equal to the original input.