Question

I’m using FrameGrabber.cs and I added its dll as reference: JockerSoft.Media.dll and Interop.qedit.

Now in Form1 code in the constructor I’m trying to retrieve all the frames in their position and save each frame to a new bitmap file on the hard disk but I can’t figure out how to do it.

I don’t know how to loop through all frames/double[] position I also wanted to see get information about how many frames there are I could get the framerate which is 17.8….

I want to get a list/array of all frames and then save each frame to hard disk and then do another manipulations on the frames.

This is the site i got the example from. Tried to look there and on source code but couldn’t figure out how to do it.

** I also have a trackBar1 in the designer I wanted to be able to scroll through all frames which also doesn’t work good.

This is my Form1 code which doesn’t work good I can get only one frame.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using ExtractFrames.Properties;
using ExtractFrames;
using JockerSoft.Media;
using JockerSoft;
using Interop.qedit;
using Interop;
using System.Runtime.InteropServices;

namespace ExtractFrames
{
    public partial class Form1 : Form
    {
        double x;
        string sf;
        double[] streamDouble ;
        string strVideoFile;
        public Form1()
        {
            InitializeComponent();
            sf = @"d:\Frames\";
            strVideoFile = @"d:\My Movie.wmv";
            for (int x = 0; x < 40; x++)
            {
                streamDouble = new double[x];
                SaveFramesFromVideo(strVideoFile, streamDouble, sf + x.ToString("D6") + ".bmp");
            }
            //getFrameRate();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private  void getFrameRate()
        {
            // Get framerate
            MediaDet md = new MediaDet();
            md.Filename = strVideoFile;
            //md.CurrentStream = 0;                     // choose the video stream
            x = md.FrameRate;
            double i = md.StreamLength;

        }

        public static void SaveFramesFromVideo(string videoFile, double[] positions, string outputBitmapFiles)
        {
            if (videoFile == null)
                throw new ArgumentNullException("videoFile");

            double streamLength;

            IMediaDet mediaDet = null;
            try
            {
                _AMMediaType mediaType;
                if (openVideoStream(videoFile, out mediaDet, out mediaType))
                {
                    streamLength = mediaDet.StreamLength;
                    Size target = getVideoSize(mediaType);
                    int iteration = 0;
                    foreach (double position in positions)
                    {
                        iteration++;
                        string outputBitmapFile = string.Format(outputBitmapFiles, iteration);
                        mediaDet.WriteBitmapBits(position, target.Width, target.Height, outputBitmapFile);
                    }
                    return;
                }
            }
            catch (COMException ex)
            {
                throw new InvalidVideoFileException();
            }
            finally
            {
                if (mediaDet != null)
                    Marshal.ReleaseComObject(mediaDet);
            }

            throw new InvalidVideoFileException("No video stream was found");
        }


        private static Size getVideoSize(_AMMediaType mediaType)
        {
            WinStructs.VIDEOINFOHEADER videoInfo = (WinStructs.VIDEOINFOHEADER)Marshal.PtrToStructure(mediaType.pbFormat, typeof(WinStructs.VIDEOINFOHEADER));

            return new Size(videoInfo.bmiHeader.biWidth, videoInfo.bmiHeader.biHeight);
        }

        private static Size scaleToFit(Size target, Size original)
        {
            if (target.Height * original.Width > target.Width * original.Height)
                target.Height = target.Width * original.Height / original.Width;
            else
                target.Width = target.Height * original.Width / original.Height;

            return target;
        }
        private static Size scaleToFitSmart(Size target, Size original)
        {
            target = scaleToFit(target, original);

            if (target.Width > original.Width || target.Height > original.Height)
                return original;

            return target;
        }


        private static bool openVideoStream(string videoFile, out IMediaDet mediaDet, out _AMMediaType aMMediaType)
        {
            mediaDet = new MediaDet();

            //loads file
            mediaDet.Filename = videoFile;

            //gets # of streams
            int streamsNumber = mediaDet.OutputStreams;

            //finds a video stream
            for (int i = 0; i < streamsNumber; i++)
            {
                mediaDet.CurrentStream = i;
                _AMMediaType mediaType = mediaDet.StreamMediaType;

                if (mediaType.majortype == JockerSoft.Media.MayorTypes.MEDIATYPE_Video)
                {
                    //video stream found
                    aMMediaType = mediaType;
                    return true;
                }
            }

            //no video stream found
            Marshal.ReleaseComObject(mediaDet);
            mediaDet = null;
            aMMediaType = new _AMMediaType();
            return false;
        }



    }


}

Answer 1

The SaveFramesFromVideo() method expects a double array filled with the percentage position in the file in seconds – since you don’t know how this relates to the length of the video you cannot use the frame rate alone. You can however save a frame at each full percentage into the file:

var streamDouble = new double[1];
for (int x = 0; x < 100; x++)
{
    streamDouble[0] = x;
    SaveFramesFromVideo(strVideoFile, streamDouble, sf + x.ToString("D6") + ".bmp");
}

If you just need that for WMV files you could also use AsfMojo instead – a complete solution would then look like this:

AsfFile asfFile = new AsfFile(@"D:\samples\sample.wmv");
AsfFileProperties fileProperties = asfFile.GetAsfObject<AsfFileProperties>();
TimeSpan duration = TimeSpan.FromTicks((long)fileProperties.PlayDuration) - TimeSpan.FromMilliseconds(fileProperties.Preroll);

var streamProps = asfFile.GetAsfObjects<AsfExtendedStreamProperties>()
                         .SingleOrDefault(x => x.StreamNumber == asfFile.PacketConfiguration.AsfVideoStreamId);

double timePerFrame = streamProps.AvgTimePerFrame / (double) 10000000 ;

double offset = 0;
while (offset < duration.TotalSeconds)
{
    using (var bitmap = AsfImage.FromFile(@"D:\samples\sample.wmv").AtOffset(offset))
    {
        if(bitmap!=null)
            bitmap.Save(string.Format(@"d:\Frames\{0}.jpg", offset.ToString("N")), ImageFormat.Jpeg);
    }
    offset += timePerFrame;
}