- H264 decoder uses the decoder output buffer as also the reference buffer for decoding future frames and the output buffer and reference buffer are reference counted versions of the same physical buffer
- H264 standard mandates padding the image by extending the last pixel of the image and this is required for the reference buffer for correct decoding
- The issue you are seeing is because you are displaying this decoded frame starting from (0,0). The actual image removing padding starts at (32,24) in the image. This info is exported in the frameInfo that is sent out of the decoder.
- DisplayLink doesnt handle startX,startY offset other than 0,0 so it is an issue when you connect decode output directly to display
To fix the issue you can either add a SwMs link or Scaler link before displayLink which will correctly handle the offset or modify dispalyLink to handle offset management. Modifying displayLink is not recommended.