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• avcodec/vvcdec : refact out deblock boundary strength stage

  4 octobre 2024, par Nuo Mi

  avcodec/vvcdec : refact out deblock boundary strength stage
  The deblock boundary strength stage utilizes 5% of CPU resources for 8K clips.
  
  It's worth considering it as a standalone stage. This stage has been relocated
  
  to follow the parser process, allowing us to reuse CUs and TUs before releasing them.
  

  • [DH] libavcodec/vvc/filter.c
  • [DH] libavcodec/vvc/filter.h
  • [DH] libavcodec/vvc/thread.c

• avcodec/vvcdec : schedule next stage only if the current stage reports no error

  23 novembre 2024, par Nuo Mi

  avcodec/vvcdec : schedule next stage only if the current stage reports no error
  If the current stage reports an error, some variables may not be correctly initialized.
  
  Scheduling the next stage could lead to the use of uninitialized variables.
  

  • [DH] libavcodec/vvc/thread.c

• Decoding the h.264 stream from a COM port

  18 mars, par Peter

  I would like to know if there is a reliable way to decode an H.264 NAL stream coming through a serial port using software.

  


  So far, I have managed to decode a single frame using a python script. In this script, I first write the incoming data to a file, and when the end-of-frame marker 00_00_00_01 appears, I display the frame using ffplay.

  


  import serial
import subprocess
import os
import time

ser = serial.Serial('COM3', 115200, timeout=1)
output_file = "output.264"

# Variable to store the ffplay process
ffplay_process = None

# Open the file for writing in binary mode
with open(output_file, "wb") as file:

    print("Writing bytes to output.264. Waiting for the end-of-frame marker 0x00000001.")

    buffer = bytearray()
    marker = b'\x00\x00\x00\x01'

    try:
        while True:
            if ser.in_waiting:  # If there is data in the buffer
                data = ser.read(ser.in_waiting)  # Read all available bytes
                buffer.extend(data)

                # Check if the end-of-frame marker is in the buffer
                while marker in buffer:
                    index = buffer.index(marker) + len(marker)  # Position after the marker
                    frame = buffer[:index]  # Extract the frame
                    buffer = buffer[index:]  # Keep the remaining data

                    print(f"Frame recorded: {len(frame)} bytes")
                    file.write(frame)  # Write the frame to the file
                    file.flush()  # Force writing to disk

                    # Close the ffplay window if it is already open
                    if ffplay_process and ffplay_process.poll() is None:
                        ffplay_process.terminate()
                        ffplay_process.wait()  # Wait for the process to terminate

                    # Play the recorded frame, reopening the window
                    ffplay_process = subprocess.Popen(["ffplay", "-f", "h264", "-i", output_file])

    except KeyboardInterrupt:
        print("\nRecording stopped.")
    finally:
        # Close the serial port and the ffplay process
        ser.close()


  


  However, each time a new end-of-frame marker is detected, the ffplay window closes and reopens to show the next frame. It will flicker when transferring the video. Is there a way to display the frames in the same window for seamless playback when streaming video ?

  


  Or is there a better approach or software that is more suited for this task ? I do not know where to start, so I will be glad for any hints.