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TOPIC: LWKS for research - syncronizing larger amounts of video material

LWKS for research - syncronizing larger amounts of video material 6 years, 11 months ago #43523

  • Hillnhutter
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Hello!
I started using lwks for my research. We are interested in how people behave when they walk to public transport stops. Especially in busy urban areas it is impossible to trace them, they just pop up from the crowd at the stop. Therefore I had the idea to film the environment around public transport stops to trace back those who approach the stop. It works, but is technical challenging. Therefore I seek for advice here.

The technical matters:
Film material: I have 6 wide angle cameras (small “action cameras” from drift innovation) that produce each 2 hours of HD film. I need HD, otherwise you don’t see much due to the wide angle of the cameras. Cameras produce mpg4 files with an h.264 codec. The cameras split up the film data in 4GB packages. After one session of filming I have about 6x 2h of video material. Each camera produces about 10GB data. Each camera captures a timestamp on the video which enables synchronization.
Computer: I’ll get fundet a new laptop: Windows 7 64bit, Intel Core i7-3520M, 8GB 1600MHZ DDR3, 128GB SATA III Solid State Disc for the operation system, AMD FirePro M4000 Graphics Card (?). I attach an 1,5 TB external hdd with two discs (7200 RPM operating in Raid 0) via an eSATA port with the computer. The external disc has also a Fire Wire 800 port (preferable?).

My problem (you may all have seen it coming!):

Obviously, I do not do much editing. I just cut the films to have the same length. The reason why I started with LWKS was the possibility to synchronize films for reviewing. When a person walks over from one camera (the captured area) to the next, I save much scrolling forth and back to find the exact time when the person appears in the next camera. Synchronization shortens significantly the process.

But as all of you saw already, the amount of data and the need for high resolution represents a challenge – or perhaps an impossibility?

I converted shorter film sections with Eye frame (format for uploading: H264 MP4 Profile High; Format for editing: Matrox I frame HD Proxy quater size). And that works great for shorter film clips. I can play 3 films parallel even on the laptop I use now.

But for the amount of data I have, the conversion of 12 hours HD video material produces some 600GB data (in 8h converting time). Further it takes ages to import so much data into LWKS. I intend to produce about 15 of such sessions (min 12 TB data!). I’m not sure either if I can work with the video material in LWKS without sitting and waiting hours - already when importing. I have no need to export something.

You are all more experienced with film than I. Do you have any suggestions … ?

Is there another converting option in Eye Frame converter I could choose?

Should I rather use the files I get from the cameras (Mpg4 h.264)? It would help if I could just link two films and so having 3 pairs. My current computer does not handle that, video just stops after 5 sec. Is there a chance that the new does better?

I do not need sound – how much would it help to delete the sound tracks?

I do not need to review each film parallel. The main advance is to open a second film in the viewer that starts at the same time I left the previous film. Are there possibilities I have not seen? Is perhaps LWKS not the right tool for me?

Any suggestions are very welcome! Thanks for reading until here!
With best regards, H.
Last Edit: 6 years, 11 months ago by Hillnhutter.

Re: LWKS for research - syncronizing larger amounts of video material 6 years, 11 months ago #43557

  • donkpow
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Is there another converting option in Eye Frame converter I could choose?

If you use ffmbc from the command line, you can cut a little overhead and time without the GUI. You can also convert the media without sound, if you like.

Do you have a second computer you can use just for converting to an editable format? Even a slow computer will free up your editing machine for work, letting the converter run unattended.

If you have lots of material you know you will not need, you can cut the clips during pre-processing.
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Last Edit: 6 years, 11 months ago by donkpow.

Re: LWKS for research - syncronizing larger amounts of video material 6 years, 11 months ago #43559

  • Hillnhutter
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Thanks for you reply,
I'm not sure what you mean with using the "ffmbc" and "cut overhad and time without the GUI". Could you explain?

Yes, a second computer would be handy. But my computer does the conversion of one film session (60GB video data) over night, which I found ok. My biggest problem is that the conversion results in 600GB data, as mentioned.

There is no vidoe material that I do not need - well, ofcourse most of it is not relevant, but that's not the point. To find the things that are relevant, and to document it (in writing), I have to rewiew all the video Material. Thats the job - not any cutting
I need to be able to review all material, play it forward and backward. Syncronizing the material from the 6 cameras that filmed simultaneous would help a lot...
Sorry, perhaps I have not been clear enough in my explanations.

Re: LWKS for research - syncronizing larger amounts of video material 6 years, 11 months ago #43562

  • donkpow
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I'm not sure what you mean with using the "ffmbc" and "cut overhad and time without the GUI". Could you explain?

EyeFrame Converter is a user interface for the ffmbc utility. It is ffmbc that does all the work when you command it from the UI. It can also be run from a command line in the Windows' terminal. Without the user interface running you can save a small amount processing power an d apply it to the processing. EFC provides you with the means to adapt the command line to ffmbc (i.e. remove audio while processing). Similar command lines can be developed and run directly from the terminal.

I am surprised suggestions on workflow have not been offered to you by the professionals.

If you are able to get rid of material you don't need, you can reduce storage needs and reduce demand for processing the preview in lwks.

If I am understanding you now, you don't need to edit video. You need to see people approaching and entering (seen from multiple cameras) the bus stop. Can you just bring up two players with time codes and make notes? Players allow "scrubbing" of the video along the time line. If you can do the job without an editor, you don't need to convert the files to an edit friendly format.
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Re: LWKS for research - syncronizing larger amounts of video material 6 years, 11 months ago #43568

  • donkpow
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Maybe you just need video mixing software. I have a discontinued program that lets me synchronize and view 4 videos at once. It will output one stream. People use similar programs for live streaming, VJ'ing, conference calls, etc. Since it doesn't do frame by frame editing, the conversion to edit friendly format is unnecessary.
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Re: LWKS for research - syncronizing larger amounts of video material 6 years, 11 months ago #43570

  • Hillnhutter
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Thank you for your Explanation, and sory for the stupid questions.
I am a professional, (just not in filming). Part of the research job is to develop a method - or you may call it 'workflow'. I work in urban planning and transportation - not with film. No one from my profession can help me with the film - unfortunately there are just no film people.
But filming helps me to see and document what I'm looking for. That¨s why I'm here

Yes, I need to see people entering and exiting the bus ... and in which directions they disapear. I film how they walk. I let 6 camers film simultaneously, as one can not capture the whole surrounding of the public transport stop.

I could do "scrubbing" in a video player - if I understand you right. But it would be very handy if all 6 films would scrub forward and backward simultaneously. When I scrub in video 2 to the time 1:23:45, I would like all other videos to scrub simultaneously as well to 1:23:45. Then I can switch between videos and see what hapens at exactly 1:23:45 - just filmed from different angels. But I haven't found a video player that synconizes (is that the right word?)these 6 films. If I got you right - syncronizing is not scrubbing - right?

Re: LWKS for research - syncronizing larger amounts of video material 6 years, 11 months ago #43571

  • donkpow
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Yes, I see. I am an amateur hobbyist with video. Others on the forum have professional film backgrounds.

I believe what you want is as I mentioned, a video mixer. The videos are synchronized in your preview window. You can move backwards and forwards in the timeline with all the synchronized videos or individually if you wish. Most also add special effects, etc. As I was considering your question I opened my tool, opened three videos, synchronized them from the start, and played all of them at once. The software is supposed to allow you to move forward and backwards under your control. It doesn't work well because it was a program under development when it was released.

A quick internet search yields several tools that do that. It allows people to live stream multiple camera inputs, or files, at once. If you don't need a finished video created in a frame by frame editor, it may be a tool worth your consideration. Mine outputs to capture software that produces a video. The transitions, between input streams, in the output are not as precise as a film editor. There is a fade transition. Still, for viewing the multiple input streams, from multiple files in your case, the preview screen provides the information you seek. Most of the paid versions have a free trial, if you want to try one.
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Re: LWKS for research - syncronizing larger amounts of video material 6 years, 11 months ago #43575

  • RWAV
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There will be a few assumptions which require testing in your exact circumstances but here's a possible workflow for you.

For $50 a year buy a LW Pro licence so you can use H.264 / AVCHD without transcoding. You will have to test that the above is true for your cameras. So spend your pennies before all is confirmed to work for you.

You won’t be able to play multiple streams on the system you describe but you should be able to view one at a time in real time. Test with your footage

Assuming you camera writes metadata that LW recognses as picture timecode and if the time on each of your cameras has been synchronised your timecodes should be close enough for your purposes – there is no way they will be frame accurate.

If LW does not see timecode – for each clip - if you can identify the camera timestamp which is not necessarily regular timecode – you can enter that manually into the LW timecode field.

Put your six matching shots with more or less matching timecodes into a LW sync group (from memory in current versions you can still elect to only update when stopped and not have the system try to play the unplayable in real time).

Setup the sync group to sync on timecode.

Now when you select any one clip to play – all the others will update to the position of the one being played - when you stop.

That seems to cover your needs?
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Re: LWKS for research - syncronizing larger amounts of video material 6 years, 11 months ago #43578

  • fischerb
Hillnhutter wrote:
I could do "scrubbing" in a video player - if I understand you right. But it would be very handy if all 6 films would scrub forward and backward simultaneously. When I scrub in video 2 to the time 1:23:45, I would like all other videos to scrub simultaneously as well to 1:23:45. Then I can switch between videos and see what hapens at exactly 1:23:45 - just filmed from different angels. But I haven't found a video player that synconizes (is that the right word?)these 6 films. If I got you right - syncronizing is not scrubbing - right?


on linux you can synchronize multimedia applications / videoplayers with jack transport mechanism to some given time code. this could work on windows too. (for example "shotcut" is available on this platform and supports jack transport synchronization -- www.shotcut.org/bin/view/Shotcut/Features)

Re: LWKS for research - syncronizing larger amounts of video material 6 years, 11 months ago #43580

  • RWAV
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Sync Groups have been part of LW for I'd guess about eight years.
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Re: LWKS for research - syncronizing larger amounts of video material 6 years, 11 months ago #43581

  • fischerb
RWAV wrote:
Setup the sync group to sync on timecode.

Now when you select any one clip to play – all the others will update to the position of the one being played - when you stop.


i don't think, this will work very well out of the box with 6 channels of raw H.264 / AVCHD material on a usual workstation, but there are some options in lightworks to optimize it a little bit. so it is very useful to suppress the synchronized playback of all sources at the same time. you can use it to preview only one source -- that will save a lot of computing power! --, but the other sources in the sync group will share the position whenever you stop the playback and change the source clip. another very helpful feature is the shortcut "Ctrl M" to resync the members of a sync group to some given position in the recording...

Re: LWKS for research - syncronizing larger amounts of video material 6 years, 11 months ago #43584

  • Hillnhutter
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To donkpow
"I believe what you want is as I mentioned, a video mixer."

Probably I just need a video mixer. I'll have a look at this option when I do not procede with LWKS. Thank you for your help!
Last Edit: 6 years, 11 months ago by Hillnhutter.

Re: LWKS for research - syncronizing larger amounts of video material 6 years, 11 months ago #43585

  • RWAV
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If you have six long AVCHD clips you want to keep in sync at all times and manipulate only one at a time but don't want to have significant transcode time then you have to either add computer grunt to the equation or accept some performance difficulties.

Anyway - no need to blindly speculate - I note now that @Hillnhutter already has a Pro Licence so she/he can simply try it and work out how to best overcome any concerns. Overcome the practicalities and the concept would certainly work like a charm.
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Re: LWKS for research - syncronizing larger amounts of video material 6 years, 11 months ago #43587

  • fischerb
RWAV wrote:
Sync Groups have been part of LW for I'd guess about eight years.


yes -- you are right! -- sometimes lightworks looks really old fashioned and not very open minded concerning much newer innovative technology

Re: LWKS for research - syncronizing larger amounts of video material 6 years, 11 months ago #43588

  • Hillnhutter
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Thank you RWAV and fischerb,
I do not yet know how to practically procede with your suggestions, but I wil consult the forum on timecodes and so on.
If I can supress that al videos that playback paralell, and just the time code updates the rest of the films when the revived video stops - perhaps that might work.
I used Sync Groups, and realized that all the previews are running when I start one video. Accepting performace limitations might be ok when it results in waiting for the computer to finish a command, but when the video playback just stops while the time line runs, I just can't see what I need to see

RWAV, you quite got it right, I have 6 long clips. Perhaps I can get around it when I split them up into chops of a quater of an hour, for example. Than I have shorter packages to syncronize. Yes, I have a licence and can just try.
But at some point the editing work might become more than I save with the syncronization...
Tahnks!
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