Creating MJPEG-stream/video with servlet, is this even possible?

[Nems Vedek]

Hello all,

I've created a servlet that fetches single images outside the servlet container/web server based on the parameters I give it and it works like this

            resp.setContentType("image/jpeg");
        
            File file = new File(camdir+"/"+savedir+"/"+date+"/"+hour+"/"+list.get(offset));
            resp.setContentLength((int)file.length());
        
            FileInputStream in = new FileInputStream(file);
            OutputStream out = resp.getOutputStream();
        
            byte[] buf = new byte[1024];
            int count = 0;
            
            while ((count = in.read(buf)) >= 0) {
                out.write(buf, 0, count);
            }    
 
            in.close();
            out.close();

The thing I was wondering could it be possible to create a somekind of a continuous stream by modifying the MIME content type and outputting all the images in the ...

            File file = new File(camdir+"/"+savedir+"/"+date+"/"+hour+"/"+list.get(offset));    

... directory?

If not, any ideas how to create a stream/video from n+1 jpeg-images?

Thanks.

[dema rogatkin]

It's quite possible and will work. What kind of clients do you expect? If just a regular browser, then mozila based browsers will be the best. I use a similar technology for a chat program:
http://7bee.j2ee.us/chathouse/readme.htm
For content type look here: http://www.ltsw.se/knbase/internet/multipart.htp

[Nems Vedek]

Originally posted by dema rogatkin:
It's quite possible and will work. What kind of clients do you expect? If just a regular browser, then mozila based browsers will be the best. I use a similar technology for a chat program:
http://7bee.j2ee.us/chathouse/readme.htm

Thanks for the reply. Yes, I'm using browser as a client. Checked out your URL but every link gives me 404 on that page (?)
[ January 23, 2006: Message edited by: Nems Vedek ]

[dema rogatkin]

Sorry it was awhile, so some links may not work anymore. Generally do search on multipart/x-mixed-replace content type. It allows <b>server push</b> model, so for mozila browsers you can just continuously send jpegs and one will be replaced by another.

[Nems Vedek]

Originally posted by dema rogatkin:
It allows <b>server push</b> model, so for mozila browsers you can just continuously send jpegs and one will be replaced by another.

Yeah, been reading about the "server push"-technology and it seems it is just the thing I need.

But then I found out a page that said "IE doesn't support server push and NN6 has severe bugs in this area."

Aarggh. Sadly IE is still the most popular browser and I really would like to have an feature that worked with IE also.

[dema rogatkin]

Actually IE supports it nicely. However it won't work for you since new pages just appended.

[Nems Vedek]

Originally posted by dema rogatkin:
Actually IE supports it nicely. However it won't work for you since new pages just appended.

Hmm, do you know is there a way to send n+1 images without appending new pages?

The servlet I wrote works just fine. Although for some reason I must hit refresh/F5 with firefox in order to get it started. With Opera it works just fine. Any idea what's wrong?

Here's some code:

        if (mode.equals("video")) {
                  
            MultipartResponse multi = new MultipartResponse(res);
    
            for (int i = 0; i < list.size(); i++) {
              multi.startResponse("image/jpeg");
              ServletUtils.returnFile(camdir+"/"+savedir+"/"+date+"/"+hour+"/"+list.get(i), out);
              multi.endResponse();
              try { Thread.sleep(250); } catch (InterruptedException e) { }
            }
    
            multi.finish();
        }    

[dema rogatkin]

Where did you get implementation of MultipartResponse? Many of them are floating around. I do not need to refresh first page for FF. Regarding IE, check HTTP spec, I remember there were some refresh headers, so maybe you can enforce IE to start from begining every part adding such headers in a part headers.