File structure for dual camera recordings

[klatch]

Pardon my ignorance but I was wondering how the dual cameras recorded in terms of file structure etc. I assume they start recording at the exact same times and are separate files of equal length - are they in the same folder but named distinctively for the different files, in different folders, or something else? Perhaps a screenshot of the file structure would assist me. Thanks.

 

[kamkar]

The DC put the files in the same folder ( Movie ) this folder also contain the RO folder ( Read Only )

But as you might know you cant have 2 files with the same name in a folder, so on this model a "A" or "B" are added to the files to tell the front from rear camera footage.
Also the files are still numbered so the "A" file might be numbered 081 and the B file 082, here is a pic of the memory card from my DC.

 

[kamkar]

Tptally the folder structure are:

DCIM -> movie & photo
Movie -> RO & video clips
RO-> video clips

Photo -> photps

 

[klatch]

Thanks for that. Do they sync up exactly such that the audio is the same on both and that, if you were editing and flipping between video tracks, that they would be in sync from the beginning of the video files or would a person need to manually sync the files? I'm noticing that most of the files seem to have the same timestamp but some have the camera B being a second later, leading me to suspect that camera B starts recording slightly after camera A does.

 

[kamkar]

Two corresponding video files from the 2 cameras dont have to be the same size, but its close,,,, this have to do with VBR ( Variable Bit Rate )

 

[kamkar]

there are just 1 MIC in the main unit, but both feeds have the sound from that one MIC.
Both feeds / videos start and stop at the same time, so only difference is the X time it take for something to pass from being in the front camera view until it come into view in the rear.
If you dont want that split second in a output video of or made with the 2 cameras, then you will have to compensate for that in editing ( my editing also can sync videos by sound / clapper ) but thats not needed as the 2 videos are in sync

 

[kamkar]

If you want i can give you for DL 4 consecutive files you can examine / play with

 

[klatch]

there are just 1 MIC in the main unit, but both feeds have the sound from that one MIC.

One mic wouldn't really affect it but I guess the answer is that the cameras might have slightly different recording start and stop times (fractions of a second) so that the audio would be slightly different if I were changing from one video track to another in a video editing program. I guess I could either try to manually sync the videos (some programs will do this by sound so that could work) if I needed to.

 

[klatch]

If you want i can give you for DL 4 consecutive files you can examine / play with

Yes, please.

 

[kamkar]

If you pointed both cameras in the same direction they will be 100% in sync, but when they point in 2 directions there are the time in between, so you will have to loose a little of the start of the rear camera if you want a output where as the oncoming car go out of view of front camera it come into view of the rear camera.

Personally i leave that split second there cuz at 50 - 80 km/h speeds on both cars it is a pretty short time where the subject are out of frame on both cameras.

You can see it in this video where i use pip and change between the 2 camera feeds.
I have not cut anything out just change winch pic are big and which one are in the little window.

 

[kamkar]

Here you go, 1.5GB ready for download.
https://mega.nz/#!f8ZknApb!41htwL9fmxpTXEVHM8Uz-ayx0wSGKhC3GZs4NxMBans

 

[klatch]

Here you go, 1.5GB ready for download.
https://mega.nz/#!f8ZknApb!41htwL9fmxpTXEVHM8Uz-ayx0wSGKhC3GZs4NxMBans

Thanks. I'll try to grab it tonight from home.

 

[kamkar]

No problemo

It is just 2 consecutive files, but from each camera, so 4 files in total.