Play 16 videoclips at once, acting interactively (Like a Rolling Stone)

[jairovital]

Recently, I watched a very interesting video clip.
This one:
http://video.bobdylan.com/desktop.html

As you can see, you can interact with it, changing channel with up/down keys.

I downloaded all 16 individual subclips.

Now, the challenge is to find a player, or another solution like flash, javascript, whatelse workaround to play locally, standalone, offline, here in my desktop computer, acting interactively.

I do not know any player that could do that. So, I ask if somebody has an idea to find a way to play interactively all that 16 subclips, able to "change channels", like the online versions does.

Anybody?

[jairovital]

I forgot to say, but it's obvious: it has to keep syncing, video and audio, as the music goes on, while the channel changes.

[DB83]

IMHO NO server could stream 16 videos simulaneously for a potentially un-limited audience and NO player could playback 16 videos simulaneously.

So.

If you have an intimate knowledge of javascript (which I do not have) you could probably work out how this visual trickery is done. Needless to say that these videos, or atleast very small chunks are stored in your cache and the script prepares the next or previous chunk while the current one plays - that minute delay while you change channels may be enough to locate that chunk giving the illusion of continuity.

Just my 2 cents.

[Bjs]

This use's ActionScript ... have a read of this link from adobe

[jairovital]

This use's ActionScript ... have a read of this link from adobe

I see it's quite complicated to do!
Nevertheless, I'll have a look on it, try to understand and duplicate here, with my videos.

Thx, Bjs.


Meanwhile, if someone has another idea... It's time to bring it to us.

Here, myself, I play with some Pascal code, and I was thinking if it's possible to write a small program to read all subclips with video component and show them as a mosaic, assigning hotkeys to change screen between mosaic and one video by time. Right now, I never wrote a program to handle videos yet and I'll study video components on Delphi first, but I guess that it's quite possible.

If someone is more experienced with Pascal/videoComponents, feel free to give me 2 cents.

[jagabo]

How it's done appears to be pretty simple. The player opens multiiple video files. But it only reads one stream to the ~3 second read-ahead buffer. When you press a channel button it switches the read-ahead to a different stream at the next i-frame. That's why there's a ~3 second delay between the time you press the button and the time the video changes. And why you can't change by more than one channel by quickly pressing the button multiple times.

[_Al_]

DVD and Blu-Ray structure was designed with this feature also.

[jairovital]

DVD and Blu-Ray structure was designed with this feature also.

DVD???

How it could be done?
How to "change channels" on DVD?

[Cornucopia]

What _Al_ was referring to is the "Multi-angle" feature. And yes, DVD/BD titles could be devised to imitate what you've seen, though there would need to be some "Button-On-Video" operations going on also to make is work more like you are thinking. While multi-angle is usually thought of as different perspectives of the same scene, it could certainly also be used for totally different images, or images where the object of focus changes. You could even get fancy with the Opcode and program it to see which stream is active and have only certain button(s) be usable based on the stream.

Note however, that DVD/BD multi-anlge maxes out at 9 different views, and there are additional bitrate and GOP structure restrictions when they are used. So 16 different images wouldn't work using this feature.

Of course, for BD, there's nothing stopping you from programming some complicated scripts using BD-J and a combination of "subtitle" graphic overlays (and the subs max stream count is 32, IIRC)...

Scott

[_Al_]

Not 16 "channels" but maximum is 8 tracks I think, it is called tracks. You can switch tracks with remote control if it has that button using HW player.

Switching those tracks with software players might not be that visually effective with up and down button, but I never tried dedicated, commercial software DVD or BD player. They might have some buttons for it. Or it is within menu.

[jairovital]

Yeah, Scott and _Al_. Good point! Multi-angle feature!
I haven't remind on that!

May you explain a little bit more? Even with just 9 video tracks.
Or point out some tutorial to work multi-angle thing?

[_Al_]

first you pick up DVD Authoring software, then google for tutorial.
DVD Lab Pro, DVD Architect, Adobe Encore, those are not free , ... I do not know if other free DVD authorings have multi-angle feature

[jairovital]

Great!

DVDLab has Multi-Angle feature and I'll look closer on it.
Now, reading the Help from the program to get better understanding...

[jairovital]

But, at the same time, I'm trying to write a small program in Delphi to read all 16 tracks at once and put some hotkeys to change the screen layout.

[_Al_]

Choosing DVD Lab Pro - You have to create those videos with care, you set GOP closed, they have to have exact same length.

Also I frame on the same position I think, never tried it though.

.. so thinking of it, Architect or Encore could be more simple solution for you, they can encode video for you.

[jairovital]

You're saying that all subclips must have the same GOP count and all segments must have same length?
And the point of each GOP must be at the same position for all subclips?

[_Al_]

Yes
never tried that mind you, using HCencoder I'd first press DVD compliant button, then check closed GOP, fixed GOP length (uncheck autogop and leave same number there) , unchecked scene change

I edited post above, Encore or Architect might encode your video with those specs (hopefully)

I would not call it subclip, it is somehow misleading, those are simple video tracks muxed together on DVD

[jairovital]

Thx, _Al_. I'll try it later, tracking your advices. Good tips!

[Cornucopia]

There are a number of restrictions with multiangle, as I mentioned earlier. Gop structure, Gop length, Closed GOP, Total length - all matching. Bitrate lower ceiling restrictions, etc. Have done about ~15-20 MA titles before. Requires great control over encoder, and authoring app that understands MA. I used Spruce DVDMaestro & Scenarist, possibly DVDArchitect on one, for them. You should get sufficient info from the authoring app about all those encoding parameters.

MA clips are all muxed together in a checkerboard fashion on the DVD to where the DVD leapfrogs to each successive GOP in the particular chosen stream.

Scott

[jairovital]

I have news.
As said before, I wrote a small program to load the videos and show them in a mosaic. This is the first step toward to the feature to "change channels".
I'm using DSPack components, which uses DirectShow and Direct9 libraries.



As seen on picture, 12 videos were loaded. I noticed some lag from 4th video ahead. The last one, 12th, were very lagged.
I checked the Task Manager and saw that the program is using only 50-55% of the CPU, not 100% as I suspected. CPU is working with idleness. So, what the problem? I don't think this is the video card. I have a nVidia GeForce 8600GT.
When the videos are running, the system tray shows too many ffdshow icons, as seen on picture below.



I'm planning to turn off visible property for all other videos, when seeing a video by time, when implementing feature "change channels", to alleviate the system. But when in mosaic layout, it's not possible.

What do you suggest to fix the lag among videos?

[jairovital]

Also, I'm planning to turn off all audio from other clips, keeping just the first one. But how to do that using DirectShow? It loads video and audio at same time, isn't it?

[jagabo]

Try playing the same video files in all windows. That will eliminate disk I/O as a possible source of problems.

[jairovital]

Try playing the same video files in all windows. That will eliminate disk I/O as a possible source of problems.

I did. And the clip runs well.

But I played again with different clips and I could see that the disk I/O's stress is just at the beginning. Now, I leave the clips playing more time and, after few seconds later, the syncing problem had gone away.

Do you know how to detach the audio from the video using DirectShow filter? I need that to play just only one audio. Bad idea to run all audio tracks if I need just one of them. I have to mute the other ones.