Merge file

[skidrow]

I write a small application to merge file, current it merge text file, audio file but not work with video file. I don't know why. this's code:

public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
		JFileChooser F = new JFileChooser();
		String[] Path = new String[2];
		for(int i=0;i<=1;i++){
			int t = F.showOpenDialog(null);
			if(t==F.APPROVE_OPTION){
				File F1 = F.getSelectedFile();
				Path[i] = F1.getPath();
			}
		}
		if(F.showSaveDialog(null)==JFileChooser.APPROVE_OPTION){
			FileOutputStream out = new FileOutputStream(F.getSelectedFile());
			for(int i=0; i<=1;i++){
				FileInputStream F1 = new FileInputStream(Path[i]);
				int n = F1.available();
				while(n>0){
					byte[] B = new byte[n];
					int k = F1.read(B);
					if(k==-1) break;
					out.write(B);
				}
				F1.close();
			}
			out.close();
		}
		JOptionPane.showMessageDialog(null, "Merge Successful...!");
	}

[Norm]

What do you mean by merge? Do you mean: Copy the contents of one file after the contents of another file so that the new file has the contents of one file in front followed by the data from the second file.

If their is a program that reads a specific type of file and processes it, like a video that is displayed, why do you think that program will understand finding more data following the contents of what it thinks is a single file?

[skidrow]

I think copy the contents of one file after the contents of another file so that the new file. I don't understand you. Can you explain to me?

[dlorde]

It's possible that a video file will have a header at the start that gives information about the video, such as the length, or number of frames, etc. Appending another file on the end wouldn't change this header information, so the merged section might not be recognised (also, the merged file might have its own header information).

I'm not a video guru, so I don't know, but it strikes me as likely. I suggest you find out how commercial video editing applications merge videos.

[skidrow]

Thanhks to dlorde, because i want to try code myself.

[Tolls]

int n = F1.available();

Quoting from the API:

Returns an estimate of the number of remaining bytes that can be read...

Bolding mine.

It would be more reliable for you to read in a loop storing into a byte buffer of some size (8k is the norm).

That said, as already mentioned there may well be header information in a video file. To be honest, I'm surprised it worked for some audio files (unless they're wav).

[skidrow]

int n = F1.available();

Quoting from the API:

Bolding mine.

It would be more reliable for you to read in a loop storing into a byte buffer of some size (8k is the norm).

That said, as already mentioned there may well be header information in a video file. To be honest, I'm surprised it worked for some audio files (unless they're wav).

I think it work with small file.
What can i do?

[Tolls]

Probably, but then it can probably read in the whole of the small file quite easily.
The usual way is something along the lines of:

byte[] buffer = new byte[about 8k];
while ((n = in.read(buffer)) > -1) {
    out.write(buffer, n);
}

That reads from in, and writes to out.
You'll have to check the API for exact details as I've done this off the top of my head, which invariably means I've got something wrong.

[skidrow]

I try, thanks to Tolls

[Tolls]

Note, this isn't going to help you at all if the file format involves headers...which is likely.

[skidrow]

I know, if i do with file format involves headers as video file,..what can i do?

[Tolls]

Leanr the file formats and see if you can do stuff involving merging the file data and relevant parts of the header.
But that involves knowing the stuff you're working with.

[skidrow]

ok, thanks you very much