Recherche avancée

Sur d’autres sites (23386)

• High latency when reading latest frame from H264 stream with FFmpeg

  22 juin 2022, par massivemoisture

  I have an app in c# that receives a H264 video stream of Android device's screen from scrcpy-server (https://github.com/Genymobile/scrcpy).

  


  I want to continously get the latest image from the stream and send it to a web app for streaming.

  


  I created a Process for ffmpeg and gave it these arguments :

  


  -fflags -nobuffer -flags low_delay -probesize 32 -re -i pipe: -g 1 -f rawvideo -pix_fmt bgr24 -an -sn pipe:

  


  I have two threads. One thread to write to stdin of the FFmpeg process the bytes that I get from scrcpy-server. The other thread to read the stdout.

  


  But the image stream that I get has very high latency, especially if there is not much movement on the device's screen. And the latency just keeps mounting up, from a few seconds behind to a minute and more.

  


  How can I fix this issue ?

  


• My ffmpeg library is not being recognised as in inter or external command when trying to convert a video in python [duplicate]

  22 avril 2024, par Shaahid Patel

  What im trying to do in python is to convert a 4k mkv video to 1080p mp4 video using the ffmpeg library.

  


  import subprocess

def convert_4k_to_1080p(input_file, output_file):
    cmd = f'ffmpeg -i "{input_file}" -crf 18 -c:v libx264 -c:a aac -s 1920x1080 "{output_file}"'
    subprocess.run(cmd, shell=True)


input_file = "c:/Users/Shaahid/Videos/Movies/Series/Arcane.S01E02.2021.2160p.UHD.WEB.AI.AV1.Opus.MULTi5-dAV1nci.mkv"
output_file = "c:/Users/Shaahid/Videos/Movies/Series/Test.mp4"
convert_4k_to_1080p(input_file, output_file)


  


  however i have been recieving the following error :
'ffmpeg' is not recognized as an internal or external command,
operable program or batch file.

  


  I was expecting my video to be converted from 4k to 1080p however I still get errors. I have tried deleted and re installing the library through pip but unfortunately the error still occurs. Im not sure what to do and can anyone kindly assist me

  


• Wrap a stream of raw H264 NALUs into a container like MP4

  7 mai 2012, par cloudraven

  I have an application that sends raw h264 NALUs as generated from encoding on the fly using x264 x264_encoder_encode. I am getting them through plain TCP so I am not missing any frames.
  I need to be able to decode such a stream in the client using Hardware Acceleration in Windows (DXVA2). I have been struggling to find a way to get this to work using FFMPEG. Perhaps it may be easier to try Media Foundation or DirectShow, but they won't take raw H264.
  I either need to :

  1. Change the code from the server application to give back an mp4 stream. I am not that experienced with x264. I was able to get raw H264 by calling x264_encoder_encode, by following the answer to this question : How does one encode a series of images into H264 using the x264 C API ? How can I go from this to something that is wrapped in MP4 while still being able to stream it in realtime

  2. I could at the receiver wrap it with mp4 headers and feed it into something that can play it using DXVA. I wouldn't know how to do this

  3. I could find another way to accelerate it using DXVA with FFMPEG or something else that takes it in raw format.

  An important restriction is that I need to be able to pre-process each decoded frame before displaying it. Any solution that does decoding and displaying in a single step would not work for me

  I would be fine with either solution