Console - Playback

The Camera streams sub-forum puts into practice the Camera streams framework. It takes into account the video pipeline in order to quickly troubleshoot various streaming issues:

My video on my console is choppy. What should I do?
My recordings always show a black screen. What should I do?
I cannot see video on my iPhone/Android/Tablet. What should I do?
Post Reply
varghesesa
Posts: 90
Joined: Thu Jul 11, 2019 9:52 pm

Console - Playback

Post by varghesesa »

Introduction
This article focuses on resolving video quality issues of a camera during playback at the console. For example, the screen is black when trying to playback a recording. Once you know the video pipeline, it becomes easy to understand and troubleshoot the issue. The Camera streams article explains all the video pipelines.

For playback at the console, the video path is:
Video path: Recording (BVR) -> Decode -> Playback window

This article explains how to resolve many playback issues by knowing the video pipeline.

Playback Issues
Video path for console playback: Recording (BVR) -> Decode -> Playback window.

The biggest difference between Playback vs Live view is the video source is coming from the recording. Make sure Live view is working first.
Garbage in = Garbage recorded.

This means the recording format (Re-encode / D2D) comes into play. This also means the hard drive is also in play since the feed comes from a file recording.


Gotcha 1: Playback is a black screen.

playback black screen.png
playback black screen.png (16.47 KiB) Viewed 24407 times

Reported issue: Usual ticket states Live view is fine but playback has a black screen.

Decode node: Hardware acceleration
Starting with the Decode node because easy to test. HA is frequently the biggest difference between live view and playback.
Live view: Camera feed -> Decode (usually on) -> Console
Playback: Recording (BVR file) -> Decode (usually off) -> Console.

Keep in mind, D2D recording is very popular due to CPU savings. Thus the Recording content is often the same content as the Camera feed. Therefore, the biggest difference between live view and playback is frequently HA.

If live view works, turn HA on/off during playback (select/unselect Also BVR). Also BVR is unselected by default. HA works well with steady streams (live view) because the GPU buffer can fill up and the hardware can process frames at a steady rate. With playback, users can go back and forth in the video using the playback controls. This use case is not conducive in general for HA so HA is frequently off during playback.
If Also BVR is selected test exhaustively. First, see if playback works at all. Then test playback by scrubbing back and forth in the recording to make sure playback works fine with Also BVR selected.

Record settings
Camera settings -> Record tab -> Video file format and compression

D2D
If your record settings are set to D2D (very popular due to CPU savings), the camera feed is saved directly to disk. D2D should work with playback if live view works.
D2D and Key frames
If you are recording Direct to Disk (D2D) and the key frame interval is sub-par, e.g. <1, then it is possible the bvr file is open for recording, but no key frames have actually been recorded yet so BI cannot play back. See Camera setup article -> Key frame section for details.

Changing the encoding settings on the camera affects the contents being saved to the file. This is how you indirectly fix playback by altering the content being recorded. See camera setup article for ideal encoding settings.

Re-encode
If you cannot get playback working with D2D, then switch to Re-encode. If playback works, you may take a CPU hit, but at least the recording can be played back on the media player on your server.

The Fix:
Change the Recording from D2D to Re-encode.
Camera settings -> Record tab -> Video file format and compression.
Create the BVR file using BI software for decoding/encoding instead of saving the camera's video.
This will lead to a bump in CPU. Monitor usage.

Playback summary
The quick fix is to switch from D2D to Re-encode. This tells BI to save the camera video stream using BI's decoding/encoding. This almost always works, but you will get the CPU bump.
If you want to troubleshoot D2D, the levers to pull are as follow
Maybe Also BVR will work.
Maybe the key frame issue resolves the problem.
Maybe simplifying your camera encoding resolves the problem


Disk issues
It goes without saying that playback will not work if you have hard disk issues. Look for Storage and Record errors in the logs. Another test is to turn the shield to red to stop recordings temporarily. Click on alerts and see if playbacks start working again.


Submitting a ticket
Summary
Effects of turning Also BVR on/off.
Screenshot of camera stats. Camera settings -> General tab.
Server health
Confirm any and all errors in the logs were addressed and resolved prior to submitting a ticket.

Remote testing
If you cannot resolve on your own, put the camera on the WAN for Remote testing.


Post Reply