Videos Not Recorded Completely...Last Section Doesn't Get Recorded

[Shitij]

So we are recording some videos for our educational project on MacBook. The last few minutes of our recordings are not getting recorded.
If we record something for 6 mins, only 4.5 minutes are seen in the output video. Could you kindly let me know what's the issue, would be obliged.

Here is my latest log of the recording, in case you require any other information, kindly let me know. Thanks.

 

[Shitij]

I have posted this wrongly in Linux forums, this is a Mac Issue, I will share the issue in Mac Forum.

 

[Tuna]

> output resolution: 2880x1800

Good luck with that.. I don't think any hardware encoder from 5 year so ago will like that, neither a CPU.

 

[Shitij]

> output resolution: 2880x1800

Good luck with that.. I don't think any hardware encoder from 5 year so ago will like that, neither a CPU.

Hi Tuna,
Do you mean to say that the system doesn't have the ability to handle such output resolution?...because the output video is coming, it's just that some end part of the recording is missing.

 

[Tuna]

Probably because it has a huge backlog with also high memory usage. Try 1920x1080.
Post a log after a recording session. It will probably report a huge encoder overload.

 

[AaronD]

Hi Tuna,
Do you mean to say that the system doesn't have the ability to handle such output resolution?...because the output video is coming, it's just that some end part of the recording is missing.

It's not that the hardware can't keep up. It's that the software is written with a certain maximum size in mind, and so it makes some assumptions that aren't true beyond that size. (the frame buffer will never be bigger than 'x', so I can put the next thing immediately after that in memory, for a possible example)

Getting something that big through anyway, that looks right, is kind of a lucky accident. Who knows what, if anything, has been clobbered in the process and turned out by chance not to matter...this time.

What do you need such high res for anyway? Are your viewers sitting just inches away from a massive screen?

 

[Shitij]

In 1920x1080 the videos are recorded fully with no trimming at the end, so it's probably an output resolution issue of 2K.
I have attached the log for your reference.

 

[Shitij]

It's not that the hardware can't keep up. It's that the software is written with a certain maximum size in mind, and so it makes some assumptions that aren't true beyond that size. (the frame buffer will never be bigger than 'x', so I can put the next thing immediately after that in memory, for a possible example)

Getting something that big through anyway, that looks right, is kind of a lucky accident. Who knows what, if anything, has been clobbered in the process and turned out by chance not to matter...this time.

What do you need such high res for anyway? Are your viewers sitting just inches away from a massive screen?

Hello Aaron,
Thanks for your response. As we were recording educational videos, we thought it would be better to record 2K so that we could zoom in on specific portions during the edit and explain in a better way.

Do you think this MacBook can record 2K or the system won't be able to keep up with it and it's better to go full HD 1920x1080?

 

[Tuna]

Note that 2K is 2048x1080. 2880x1800 is closer to 4K which is 3840x2160. 4K is 4(!) times the data of 2K. You would require very good or special hardware to manage that.

 

[Tuna]

You will have to find the sweet spot for your hardware. It may require turning a lot of knobs to find what fits your desired needs.

You should always check the log for these messages after the recording:

19:41:34.585: Output 'adv_file_output': Number of lagged frames due to rendering lag/stalls: 2 (0.1%)
19:41:34.695: Video stopped, number of skipped frames due to encoding lag: 48/3416 (1.4%)

Ideally they are close to 0%.

 

[AaronD]

As we were recording educational videos, we thought it would be better to record 2K so that we could zoom in on specific portions during the edit and explain in a better way.

Is it possible to zoom in live (likely following a pre-planned script, but not necessarily), and record the result in 1920x1080?

 

[Lawrence_SoCal]

Note that 2K is 2048x1080.

My understanding is that the most common 2K resolution is aka Quad HD = 2560x1440p

 

[Tuna]

2K resolution - Wikipedia

en.wikipedia.org