seek bar in mp4 issues

[cyr0nk0r]

So I have an IP8M-2597EB-28MM, I'm shipping footage via FTP over a gigE network.
The camera is running the latest firmware (2020-03-30) and I'm recording on events with H.265 at 4k/30fps with 4096 bitrate.

The issue I'm experiencing is when I look at the MP4 video files everything is fine. The file plays correctly, its not choppy or glitchy or anything. And if I watch the video 100% from start to finish without moving around things work great. The issue is if I try and seek around using the seek bar.

I have the k-lite codec pack installed on my machine with all the codecs one could want. And I'm using media play classic for playback. What I've noticed is that if I try and seek around, the video (in this case a 57 second test video) will only 'seek' to either 20 seconds or 40 seconds into the video. So it seems there is something happening to the video every 20 seconds that allows you to seek, but anything in between you can't manually seek to.

Has anyone else experienced this or have any suggestions on how I can adjust the settings to be able to seek the MP4's to any spot in the video?

EDIT: so as a test I just installed VLC player onto my machine to try that. With VLC I am able to properly seek to any part of the video. Anyone have any idea why it works in VLC but not in MPC?
(answered: in doesn't work in MPC because I have 'fast seek' (on keyframe) enabled in the 'tweaks' section of the MPC options.)

EDIT2: So my research tells me this issue may be related to GOP size in the encoding process, or keyframes. What is the default keyframe interval for the main stream? In the sub stream for this particular camera I can specify the frame interval between 30-150 seconds, but that option is not available for the main stream.

[cyr0nk0r]

So it seems someone else has seen/requested this issue.
https://amcrest.com/forum/ip-cameras-f1 ... 13217.html
He is noticing the same behavior (keyframe interval is 10 seconds)

Question remains, is there a way to adjust the keyframe interval for the main stream? Or some FPS/bit rate combination that will increase keyframes to <10sec?

[jack7]

All my Amcrest cameras have frame interval setting. Your 4K 30fps may be pushing the limit, so maybe they turned off frame interval setting. Try setting 15 fps and see if interval setting comes back. If so, try increasing fps to see how high it will go and have interval setting.
Or just use VLC or other another capable video player.

[cyr0nk0r]

Great idea. So I've played with the settings.
First off, with 'smart codec' set to 'on', the frame interval is not available no matter what frame rate you set.
I've also tested with various settings and although the keyframe interval can only be set as low as 30, for this particular issue it doesn't seem to matter.
The culprit rests squarely with the 'smart codec'.

As soon as I turned off smart codec and rebooted the camera, all new recordings started being able to seek correctly in MPC. All other settings (frame rate, bit rate, etc) remained the same. So it seems to have something to do with the smart codec.

I am satisfied with this resolution by disabling the smart codec. So I leave this thread for anyone else with similar issues so they can find this later down the road.

EDIT:
https://support.amcrest.com/hc/en-us/ar ... art-Codec-
I wish I had seen this sooner. Apparently even Amcrest recommends you disable smart codec.