Ask a Question
GoPro Support Hub Ask a question. Share an answer. Find a solution. Stay stoked.
Announcements
Is your GoPro gear up to date? Check to see If it is on our Update page.
Cameras
Reply
Tourist
Posts: 5

why are timewarp videos so big

[ New ]

I have a Hero7 Black. I just tried out timewarp and it seems to be a really nice feature. That is until I looked at the file sizes.
For a 1 minute, 17 second recording, the file size was 568MB
For a 44 second recording, the file size was 327MB
I recorded these timewarps at 10x and 15x.

My expectancy was that the camera would strip out unused frames leaving reasonable file sizes. What seems to be happening here is that all the frames are being stored and only a fraction viewed.

Can you clarify what is happening please and how I might be able to make these recordings smaller.

Backpacker
Posts: 7,581

Re: why are timewarp videos so big

[ New ]

If you're recording the timewarp at 4K, then those sizes look about right.  I just made a highly compressed 4K clip that lasted 1 minute and it's 372MB in size.  Yet if I drop the resolution to 1080P it's only 93MB in size.

 

So, if you want smaller clips you can always drop the resolution to 1080P.  

Tourist
Posts: 5

Re: why are timewarp videos so big

[ New ]

Apologies, more questions....


Should have mentioned that I recorded timewarp at a resolution of 1440. The max resolution of the camera for timewarp (at 4:3) is 2.7K at this aspect ratio.


The concern I have is that at this resolution, the file sizes are approximately 500MB per 60 seconds or 30GB for an hour of recording. This still seems a little large. Maybe its because gopro doesnt compress the images, in saying that the file sizes are approximately 10 times bigger than I would expect from a compressed video (very roughly)?


I purchased a 32GB card thinking that it would be big enough after looking at this, I think I should start looking at 256GB card.


Maybe gopro should consider having an additional mode/setting that compresses videos for people that are not likly to edit them afterwards??


Does anyone know of software that can take these videos and compress them on a PC. This would at least reduce the storage space needed?

 

 

 

 

 

Backpacker
Posts: 7,581

Re: why are timewarp videos so big

[ New ]

The filesize is about right considering what you are recording and the format you are recording in.  When you can pickup an 8TB hard disc for under $150, 500mb doesn't seem all that big.  If you do decide to compress your video's, you will lose a lot of quality, so keep that in mind.  For fast easy video compression you can always use a tool like "Handbrake".  It's free and comes with plenty of options.   Yes, I would definitly upgrade from a 32gb memory card.  I use 128gb cards in my camera's and off load footage on a regular basis.

Tourist
Posts: 5

Re: why are timewarp videos so big

[ New ]

You nearly had me convinced until I did the following test...

I recorded a 5 minute time warp video in 1080 = 2.3GB
I recorded a 5 minute video in standard 1080 (50fps) = 0.9GB

These video sizes should be the same, timewarp looks like its more than double the size it should be. Why are they not the same.

It still looks to me that the file sizes are too big.

Explorer
Posts: 13,055

Re: why are timewarp videos so big

[ New ]
TimeWarp is using Photos and then merging them into a video. Video is just video, so it will be smaller. You can't compare the two thinking you should get the same result.

One photo has a size of about 4.8 MB. A frame grab from a 4K video is about 2MB, so no, they are not the same. I'm not sure if the TimeWarp compresses to a 24fps or 30fps, but lets use the smaller number to determine expected file size.

A 5 minute TimeWarp at 10x will give you 30 seconds of video
At 24fps the 30 second video clip will have 720 photos
720 photos x 4.8 MB = 3456 MB (3.456 GB)
Compression is then applied based on the resolution you are using.

If you don't want to higher quality, then just record in 1080p video and then speed it up in post.
Tourist
Posts: 5

Re: why are timewarp videos so big

[ New ]

1080p defines the number of pixels (https://en.wikipedia.org/wiki/1080p). I think its misleading by confusing the difference between photos and videos. Put simply, timewarp 1080p (16:9) and normal video 1080p (16:9) should cause the camera to capture the same number of pixels from the sensor. At least thats my understanding of it because if it captures and saves data from a different number of pixels, its not 1080p.

 

There may be a discrepancy in whatever framerate that the timewarp saves videos in? I captured the comparative 1080p video at 50fps. I cant find any details on what framerate timewarp videos are captured at. You suggest 24fps so this should lead to even smaller file sizes than the 1080p video I captured.

 

The bottom line is that assuming the framerate is the same, then the video size should also be the same but its not.

 

Maybe this is a firmware bug?

Explorer
Posts: 13,055

Re: why are timewarp videos so big

[ New ]
It's not a firmware bug.
Tourist
Posts: 5

Re: why are timewarp videos so big

[ New ]

I still think its a firmware bug.

 

Assuming that the color depth is the same in both cases and the camera captures data from only 1920x1080 pixels as the settings dictate, then the video sizes should be the same. Looking at the file properties, the data rate is unexpectedly high for the timewarp video. This is unusual since the frame rate in timewarp is less than half of that of the standard video.

 

Just to clarify, a picture taken at 1920x1080 should be the same as a framegrab at 1920x1080. Its the same number of pixels!

 

This is a bug!

 

Does anyone know how do I go about reporting bugs in the firmware?

 

For a standard video:
Resolution: 1920*1080
Data Rate: 24007kpbs
Frame rate: 50fps
Audio bit rate: 189kpbs
Audio sample rate: 48kHz

 

For a timewarp video:
Resolution: 1920*1080
Data Rate: 60010kbps
Frame rate: 25fps
Audio bit rate: NA
Audio sample rate: NA

Explorer
Posts: 13,055

Re: why are timewarp videos so big

[ New ]
Your wrong. What you are not taking into account is the bitrate.

We can go round and round with this forever, but you need to do more research. What you are proposing is that every camera taking a 1080p video will have the same file size based on the number of pixels. This has very little to do with the file size.

It's not a bug.

Do yourself a favor and just enjoy the camera.