20 sec delayed replay

[sportsman]

hi,guys.

my goal:
To support and help the student in learning and teaching movements and techniques in physical education lessons or training sessions.
The vlc-player delays the playback of a recorded performance by the amount of time (20 sec) required by an athlete to get to the computer screen. The athlete can then watch the technique he has just practised on the screen and receives scientifically proven, efficient feedback about his performance of the movement. While one athlete is watching his own performance, the next person can be performing the test.

my equipment:
vlc player Version 1.1.12 The Luggage (Intel 64bit)
MacBook Pro OS X Version 10.7.2 2,53 GHZ Intel Core 2 Duo; 4GB 1067 MHz DDR3
I am looking for a appropriate webcam (maybe with firewire), any suggestions?
ideally waterproof for the swim lessons.

my first trial:
1.Command+R iSght input: qtcapture://
preferences (all) -> Sout-Stream -> Display -> Delay 20000
I can see me , but without delay. I suggest the number limited to four-digits

2.

Code: Select all

/Applications/Video/VLC.app/Contents/MacOS/VLC qtcapture:// --sout-display-delay=20000

But the output is the same as with the normal GUI.

Any suggestions are appreciated
Merry Christmas!
jens

[sportsman]

and a happy new year

[crackstone]

I just tried to achieve what you described. I guess you'll need to stream your iSight or camera device and set a dts delay on the one side and play the stream with a udp caching value high enough. I got a 21 second delay working. Maybe there's a better way to do this - but this one worked.

Try the following:
(1) Stream with dts-delay

Code: Select all

/Applications/VLC.app/Contents/MacOS/VLC -vv qtcapture:// --sout='#transcode{vcodec=h264,vb=768,fps=25.0,scale=1}:standard{access=udp,mux=ts{dts-delay=9000},dst=239.0.0.5}'

(2) Play with udp-caching

Code: Select all

/Applications/VLC.app/Contents/MacOS/VLC udp://@239.0.0.5 --udp-caching=9000

All together this should add up to a 21 second delay.

Concerning your other question on an appropriate webcam/waterproof thingy.
My first though: those GoPro helmet camera - but i never used one and am not sure if they can act as a live cam
My second thought: right now with VLC 1.1.12 you can only access your iSight camera as a video device, hence you're stuck with iSight. This will change with the new upcoming VLC. However you can try and build VLC from the latest source and test qtcapture with a video device other than your iSight cam.

//crackstone

[sportsman]

Hi crackstone,
thank you very much für your suggestions
I tried your code and it works

GREAT!!!!

You are my hero!

many thanks
jens