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• mpegvideo : allocate sufficiently large scratch buffer for interlaced vid

  16 mai 2013, par Jindrich Makovicka

  mpegvideo : allocate sufficiently large scratch buffer for interlaced vid
  MPV_decode_mb_internal needs 3 * 16 * linesize bytes of scratch buffer
  For interlaced content, linesize is multiplied by two after the allocation
  
  of the scratch buffer, and the dest_cr pointer ends past the buffer.
  This patch makes ff_mpv_frame_size_alloc allocate a total of
  
  (aligned line_size) * 2 * 16 * 3 bytes, which suffices even for the
  
  interlaced case.
  CC:libav-stable@libav.org
  Signed-off-by : Jindrich Makovicka <makovick@gmail.com>
  
  Signed-off-by : Anton Khirnov <anton@khirnov.net>
  

  • [DBH] libavcodec/mpegvideo.c

• How to capture desktop using ffmpeg ? getting error when stop recording : System.InvalidOperationException : 'StandardIn has not been redirected.'

  4 octobre 2023, par SharonHemed

  I want it to record the entire desktop then when stopping to save the file to the hard drive. and to hide without the console window of the ffmpeg.

  


  but getting this exception error. and i'm setting the RedirectStandardInput to true.
so i'm not sure why it's showing this error.

  


  The exception error is on the line

  


  process.StandardInput.BaseStream.Write(qKey, 0, 1);


  


  The full code

  


  using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using NAudio.CoreAudioApi;
using NAudio.Wave;

namespace Desktop_Recorder
{
    public partial class Form1 : Form
    {
        Process process;

        public Form1()
        {
            InitializeComponent();

            process = new Process();
            Start(@"d:\test.mp4", 30);
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            
        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            Stop();
        }

        public void Start(string FileName, int Framerate)
        {
            process.StartInfo.FileName = @"d:\ffmpeg\ffmpeg.exe"; // Change the directory where ffmpeg.exe is.  
            process.EnableRaisingEvents = false;
            process.StartInfo.WorkingDirectory = @"D:\"; // The output directory  
            process.StartInfo.Arguments = @"-y -f gdigrab -framerate " + Framerate +
                " -i desktop -preset ultrafast -pix_fmt yuv420p " + FileName;
            process.StartInfo.UseShellExecute = false;
            process.StartInfo.CreateNoWindow = false;
            process.StartInfo.RedirectStandardInput = true; //Redirect stdin
            process.StartInfo.RedirectStandardError = true;
            process.Start();
            System.Threading.Thread.Sleep(3000);  //Wait 3 seconds (for testing).
            Stop();
        }

        public void Stop()
        {
            byte[] qKey = Encoding.GetEncoding("gbk").GetBytes("q"); //Get encoding of 'q' key
            process.StandardInput.BaseStream.Write(qKey, 0, 1); //Write 'q' key to stdin of FFmpeg sub-processs
            process.StandardInput.BaseStream.Flush(); //Flush stdin (just in case).
            process.Close();
        }


        private void btnStartRecording_Click(object sender, EventArgs e)
        {

        }
    }
}


  


• FFmpeg, animation types : How to move the video screen along the large images ? [duplicate]

  18 décembre 2019, par ArmKh

  This question already has an answer here :

  • generate video containing scrolling image
    
    1 answer
    

  My output video sizes are 1280x720. And I have an images with these sizes

  1. 3000x1200
  2. 1200x2000

  So, I need to animate the large images inside the small video frames. The first image should be animated from right to left and the second one from top to bottom. In other words it will be something like moving screen along the pictures

  In this video example you can see the animations like that.
  So, how I can do it ?