Rockbox Technical Forums

Support and General Use => Recording => Topic started by: TripleKill on May 25, 2008, 09:42:43 AM

Title: Can I theoretically record video?
Post by: TripleKill on May 25, 2008, 09:42:43 AM
Hello everyone. Greetings from Russia!

I have an iAudio X5 player and I recently got a crazy idea: what if it's possible to record video on HDD if a webcam is attached to USB Host? Of course I understand that it requires a special program or addon in firmware. But there are some more questions:

1). Is the USB Host's speed enough to record stream data?
2). Can I compress video "on-the-fly" or it only can be recorded uncompressed?
3). About the size. I consider 160*128 size as uncomrehensible. So I'd record video with better resolution even if it will be unplayable on iAudio - I can easily convert it at home with JetAudio.

An uncompressed 2hrs video file with 720*576 px at 25 fps is about 18Gb in
size. I just think how much I can record having 160*128 px resolution (though I want to have 320*240 or 640*480)... And if it's possible to compress stream on-the-fly...

Any comments?

P.S. Sorry for my poor English...
Title: Re: Can I theoretically record video?
Post by: petur on May 25, 2008, 10:44:55 AM
1. usb host is not implemented (yet)
2. there is no usb driver for your webcams

once both of the above issues are solved, you can write code to record video ;)
Title: Re: Can I theoretically record video?
Post by: Davide-NYC on May 25, 2008, 11:53:51 AM
I have nothing useful to add but wanted to say that *if* this were implemented it would be a stunning achievement IMO. I would use it.
Title: Re: Can I theoretically record video?
Post by: TripleKill on May 28, 2008, 01:39:41 PM
2 petur:
Thanks for your useful information)

No, seriously, is iAudio X5 so good that there are only those obstacles you mentioned in the way?
Title: Re: Can I theoretically record video?
Post by: LambdaCalculus on May 28, 2008, 02:11:29 PM
That's about it. Once USB host is implemented, and you can get a USB driver for your webcam written, what would stop you from recording video? ;)
Title: Re: Can I theoretically record video?
Post by: AlexP on May 28, 2008, 05:06:21 PM
Can USB handle the sustained data rate (I assume the video would be uncompressed)?  I haven't looked, so the answer may well be, yes by miles, but I just thought I'd through it out there.
Title: Re: Can I theoretically record video?
Post by: TripleKill on May 29, 2008, 03:02:41 AM
Thanks to you all.
If anyone has something else to say about the problem, please post here.

A question of interest: did you try to communicate with player manufacturers and to exchange experience? Or maybe they tried? The work done here is great and some posts I have read contain brilliant ideas.
Title: Re: Can I theoretically record video?
Post by: petur on May 29, 2008, 03:37:13 AM
A question of interest: did you try to communicate with player manufacturers and to exchange experience? Or maybe they tried? The work done here is great and some posts I have read contain brilliant ideas.

Player manufacturers don't like people messing with their player and say it voids warranty. So we don't expect much help from them.

Sandisk handed some players to us but nothing more, probably to get some media attention and sell more players, not to really help us.

Title: Re: Can I theoretically record video?
Post by: TripleKill on May 30, 2008, 10:23:07 AM
That's a pity. Anyway, you do the right thing here.
Thanks everyone. Have a pleasant and productive work.
Title: Re: Can I theoretically record video?
Post by: FleetAd on June 05, 2008, 05:14:08 AM
I wonder if this could be done through the ViPods jack, or through the USB?

T'would be intresting, and helpful, though could raise legal action.
Title: Re: Can I theoretically record video?
Post by: Zardoz on June 05, 2008, 02:33:57 PM
what can the line in on the subpack handle??
just curious
Title: Re: Can I theoretically record video?
Post by: saratoga on June 07, 2008, 04:26:48 PM
what can the line in on the subpack handle??
just curious

Linein is audio.
Title: Re: Can I theoretically record video?
Post by: Zardoz on June 08, 2008, 07:34:07 AM
I don't really know how these things work but how can the input connector differentiate between data?
Title: Re: Can I theoretically record video?
Post by: saratoga on June 08, 2008, 12:18:57 PM
I don't really know how these things work but how can the input connector differentiate between data?

If you're asking if you can record video through line in, thats not going to work because sample rate is too low for video.  And anyway, the hardware needed to buffer and convert a video signal into something that could be passed through a line in would be considerably more complicated then just building a real digital video recorder.
Title: Re: Can I theoretically record video?
Post by: Zardoz on June 08, 2008, 01:01:03 PM
I figured it was not gonna work just wondered about the wherefores and whatnots. really what i was asking was whats the most can be sent thru 'line-in'