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• fftools/ffmpeg_mux_init : apply encoder options manually

  9 avril 2024, par Anton Khirnov

  fftools/ffmpeg_mux_init : apply encoder options manually
  Do not pass an options dictionary to the avcodec_open2() in enc_open().
  This is cleaner and more robust, as previously various bits of code
  
  would try to interpret the contents of the options dictionary, with
  
  varying degrees of correctness. Now they can just access the encoder
  
  AVCodecContext directly.
  Cf. 372c78dd42f2b1ca743473b9c32fad71c65919e0 - analogous change for
  
  decoding.
  A non-progressive field order is now written on the container level in
  
  interlaced ProRes encoding tests.
  

  • [DH] fftools/ffmpeg_enc.c
  • [DH] fftools/ffmpeg_mux_init.c
  • [DH] tests/ref/vsynth/vsynth1-prores_444_int
  • [DH] tests/ref/vsynth/vsynth1-prores_int
  • [DH] tests/ref/vsynth/vsynth2-prores_444_int
  • [DH] tests/ref/vsynth/vsynth2-prores_int
  • [DH] tests/ref/vsynth/vsynth3-prores_444_int
  • [DH] tests/ref/vsynth/vsynth3-prores_int
  • [DH] tests/ref/vsynth/vsynth_lena-prores_444_int
  • [DH] tests/ref/vsynth/vsynth_lena-prores_int

• Can't view and record graph at the same time using FFMpegWriter [closed]

  7 juillet 2024, par Barkın Özer

  So this code is used for graphing and logging sensor data coming from bluetooth ports. I wanted to add an function that will record the graph in mp4 format. In order to achieve this I used ffmpegWriter. The issue is while this code records the graph I can't view the graph at the same time.

  


  import serial
import matplotlib.pyplot as plt
from matplotlib.animation import FuncAnimation, FFMpegWriter
import openpyxl
from datetime import datetime

# Constants
GRAVITY = 9.81  # Standard gravity in m/s²

# Initialize serial connections to HC-06 devices
ser_x_accel = serial.Serial('COM4', 9600, timeout=1)  # X-axis acceleration data
ser_y_angle = serial.Serial('COM11', 9600, timeout=1)  # Y-axis angle data

# Initialize empty lists to store data
x_accel_data = []
y_angle_data = []
timestamps = []

# Initialize Excel workbook
wb = openpyxl.Workbook()
ws = wb.active
ws.title = "Sensor Data"
ws.append(["Timestamp", "X Acceleration (m/s²)", "Y Angle (degrees)"])

# Function to update the plot and log data
def update(frame):
    # Read data from serial connections
    line_x_accel = ser_x_accel.readline().decode('utf-8').strip()
    line_y_angle = ser_y_angle.readline().decode('utf-8').strip()
    
    try:
        # Parse and process X-axis acceleration data
        x_accel_g = float(line_x_accel)  # Acceleration in g read from serial
        x_accel_ms2 = x_accel_g * GRAVITY  # Convert from g to m/s²
        x_accel_data.append(x_accel_ms2)
        
        # Parse and process Y-axis angle data
        y_angle = float(line_y_angle)
        y_angle_data.append(y_angle)
        
        # Append timestamp
        timestamps.append(datetime.now())

        # Limit data points to show only the latest 100
        if len(x_accel_data) > 100:
            x_accel_data.pop(0)
            y_angle_data.pop(0)
            timestamps.pop(0)

        # Log data to Excel with timestamp
        timestamp_str = timestamps[-1].strftime("%H:%M:%S")
        ws.append([timestamp_str, x_accel_data[-1], y_angle_data[-1]])

        # Clear and update plots
        ax1.clear()
        ax1.plot(timestamps, x_accel_data, label='X Acceleration', color='b')
        ax1.legend(loc='upper left')
        ax1.set_ylim([-20, 20])  # Adjust based on expected acceleration range in m/s²
        ax1.set_title('Real-time X Acceleration Data')
        ax1.set_xlabel('Time')
        ax1.set_ylabel('Acceleration (m/s²)')
        ax1.grid(True)

        ax2.clear()
        ax2.plot(timestamps, y_angle_data, label='Y Angle', color='g')
        ax2.legend(loc='upper left')
        ax2.set_ylim([-180, 180])
        ax2.set_title('Real-time Y Angle Data')
        ax2.set_xlabel('Time')
        ax2.set_ylabel('Angle (degrees)')
        ax2.grid(True)

        # Update text boxes with latest values
        text_box.set_text(f'X Acceleration: {x_accel_data[-1]:.2f} m/s²')
        text_box2.set_text(f'Y Angle: {y_angle_data[-1]:.2f}°')
        
        # Save the workbook periodically (every 100 updates)
        if frame % 100 == 0:
            wb.save("sensor_data.xlsx")
        
    except ValueError:
        pass  # Ignore lines that are not properly formatted

# Setup the plots
fig, (ax1, ax2) = plt.subplots(2, 1, figsize=(10, 8))
text_box = ax1.text(0.05, 0.95, '', transform=ax1.transAxes, fontsize=12, verticalalignment='top', bbox=dict(boxstyle='round', facecolor='wheat', alpha=0.5))
text_box2 = ax2.text(0.05, 0.95, '', transform=ax2.transAxes, fontsize=12, verticalalignment='top', bbox=dict(boxstyle='round', facecolor='wheat', alpha=0.5))

# Animate the plots
ani = FuncAnimation(fig, update, interval=100)  # Update interval of 100ms

# Save the animation as a video file
writer = FFMpegWriter(fps=10, metadata=dict(artist='Me'), bitrate=1800)
ani.save("sensor_data.mp4", writer=writer)

plt.tight_layout()
plt.show()

# Save the workbook at the end of the session
wb.save("sensor_data.xlsx")



  


  I tried using OpenCV to record the graph but then I didn't even got any recording. I think solving this issue with my original code would be a better approach.

  


• washed out colors when converting h264 into vp9 using ffmpeg [closed]

  31 juillet 2024, par apes-together-strong

  I'm trying to convert an h264 video to vp9/opus webm.
Every attempt so far has had washed out colors.
Is there a fix for this issue or is it just the way h264->vp9 conversion is ?

  


  ffprobe of the source file :

  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test1.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    creation_time   : 2024-07-30T17:03:10.000000Z
    com.android.version: 10
  Duration: 00:01:04.07, start: 0.000000, bitrate: 20198 kb/s
  Stream #0:0[0x1](eng): Video: h264 (High) (avc1 / 0x31637661), yuvj420p(pc, bt470bg/bt470bg/smpte170m, progressive), 1920x1080, 20001 kb/s, SAR 1:1 DAR 16:9, 30 fps, 30 tbr, 90k tbn (default)
    Metadata:
      creation_time   : 2024-07-30T17:03:10.000000Z
      handler_name    : VideoHandle
      vendor_id       : [0][0][0][0]
    Side data:
      displaymatrix: rotation of -90.00 degrees
  Stream #0:1[0x2](eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 96 kb/s (default)
    Metadata:
      creation_time   : 2024-07-30T17:03:10.000000Z
      handler_name    : SoundHandle
      vendor_id       : [0][0][0][0]