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• Capturing actual video stream quality using FFmpeg and FFplay – smooth recording but stuttering stream

  3 décembre 2024, par Karlitos Bemowo

  I’m trying to analyze the quality of a video stream over a local network using FFmpeg. My goal is to capture the actual streamed video (with all artifacts, stuttering, or buffering) as experienced in real-time, rather than a reconstructed, smooth output. Currently, the recorded video is perfectly smooth, but the live stream played using ffplay exhibits noticeable stuttering. Additionally, while the duration of the recording matches the original video, the live stream lasts longer, likely due to buffering caused by network instability.

  


  Here are the commands I’m using :
Sender :
ffmpeg -re -i file.mp4 -c:v libx265 -preset veryfast -f mpegts udp ://192.168.1.26:1234
Receiver :
ffmpeg -i udp ://192.168.1.10:1234 -c copy received_fhd.mp4 -fflags nobuffer

  


  The recorded file received_fhd.mp4 plays back perfectly, with no stuttering or frame drops, even though the network stream has visible issues when viewed in real-time with ffplay.The recorded file has the same duration as the original video (fhd.mp4), while the real-time stream playback with ffplay takes longer, suggesting delays caused by buffering or network issues. Same issue with with other codes for example vp9.

  


  GOAL : I want to capture the actual streamed video as experienced in real-time, with all stuttering, buffering, and artifacts included. This would allow me to analyze the network's impact on the video quality effectively.

  


  Questions :

  


  

  1. How can I modify my commands to record the video stream exactly as it is experienced in real-time, including any network-induced issues ?

  


  2. Is there a way to configure FFmpeg to behave more like ffplay in terms of handling and recording the stream ?

  


  


  Any guidance or alternative approaches would be greatly appreciated. Thank you !

  


  Experimented with different codecs (e.g., H.265, VP9) and output formats. Older codes has no delay in tranmission so I didn't notice the issue at frist.

  


  Explored various ffmpeg options like -fflags nobuffer and -c copy (as documentation says " For example, -codec copy or -codec : copy would copy all the streams without reencoding."), but it still doesn’t replicate the actual stream behavior.

  


• Playing RTP stream on Android 4.1.2 (Jelly Bean) [closed]

  27 décembre 2024, par Homie_Tomie

  I'll try to keep it quick. Using FFMPEG I started a stream on my PC. Here is the code :

  


  import subprocess

def start_stream():
    command = [
        'ffmpeg',
        '-f', 'gdigrab',  # Desktop capture (Windows)
        '-framerate', '15',  # Low framerate for higher performance
        '-i', 'desktop',  # Capture desktop
        '-c:v', 'libx264',  # Video codec (H.264)
        '-preset', 'ultrafast',  # Ultra-fast encoding preset for minimal latency
        '-tune', 'zerolatency',  # Zero latency for real-time streaming
        '-x264opts', 'keyint=15:min-keyint=15:no-scenecut',  # Frequent keyframes
        '-b:v', '500k',  # Low bitrate to minimize data usage and reduce latency
        '-s', '800x480',  # Resolution fits phone screen and helps performance
        '-max_delay', '0',  # No buffering, instant frame output
        '-flush_packets', '1',  # Flush packets immediately after encoding
        '-f', 'rtp',  # Use mpegts as the container for RTP stream
        'rtp://192.168.72.26:1234',  # Stream over UDP to localhost on port 1234
        '-sdp_file', 'stream.sdp'  # Create SDP file
    ]
    
    try:
        print("Starting stream...")
        subprocess.run(command, check=True)
    except subprocess.CalledProcessError as e:
        print(f"Error occurred: {e}")
    except KeyboardInterrupt:
        print("\nStream interrupted")

if __name__ == "__main__":
    print("Starting screen capture...")
    start_stream()


  


  Now, when I start the stream I can connect to it in VLC when I open up the stream.sdp file. Using the same method I can open up the stream on my iPhone, but when I try to open it on my old Android phone the stream connects but the screen is black. However, when I turn the screen I can see the first frame that was sent to the phone. Why does the stream not work ?

  


  I will be thankful for any and all advice :)

  


• Revision 29188 : 2 options de plus pour personnaliser la page d’activation de la mutu : * ...

  15 juin 2009, par real3t@… — Log

  2 options de plus pour personnaliser la page d’activation de la mutu :
  * ’branding’ : texte libre en HTML
  * ’branding_logo’ => logo (sous forme de HTML)