Stuttering Playout, Dropped Frames, Glitches

If you experience stuttering video or audio, or even small glitches during the playout, you find here some ideas to lookout for. Most likely this happens, because the system is not able to deliver the video frames fast enough for the decoding process of PLAYDECK. This mostly results in hearable stuttering of audio. If its glitches here and there, but the file runs smooth otherwise, something is interfering with the playout process, causing a bottleneck.

Quickstart: Symptoms and Fix

Please note, that if you see glitches in the PREVIEW, it doesnt mean that there are glitches in the Playout.

Constant Stuttering in Audio Output
This is a clear indicator of a system overload. Use common video codecs (H.264). Use a decent NVIDIA GPU. Avoid transcoding. Avoid HTML/Overlays. Disable Channel names in Previews. Reduce resolution. Use a dedicated SDI output card (e.g. Decklink).

Frame Drops on start playing a new Clip, otherwise ok
This indicates a bottleneck from HDD or GPU or CPU. Use SDD. Disable any form of HDD/SDD sleep. Set energy settings to maxium performance. Use lates NVIDIA driver. Play files locally instead of network or NAS. Check for possible overheating problem of GPU. Disable CPU sleep/parking (pref. on Notebooks)

Some glitches here and there, otherwise ok
There is something external interfering with the decoding process. Close all Apps, especially Broswer, or any App that has access to the GPU. Disable Anti-Virus. Check for GPU/CPU peaks in Task Manager.

Find more detailed approaches down below:

Clip as Bottleneck (DNxHD 185x, HAP or ProRes Codec + MXF files)

ProRes unfortunately is not well suited for playback on Windows-based systems. This is because Apple does not provide Windows-optimized codecs. DNxHD 185x, HAP Codecs or MXF files cant be decoded via GPU and are forced to be decoded on the CPU.

In both cases, we recommend switching to H.264 or H.265 instead. For Alpha we recommend HAP. We also recommend to use clips with the same resolution and framerate as the PLAYDECK playlist setting to avoid transcoding.

Harddisk/Network as Bottleneck

Please make sure, that the data rate of your clips can be transferred flawlessly through your system. if your clips run over the network, test them on your local harddisk.

In PLAYDECK under Workflow -> Advanced Settings, disable “Anti HDD Sleep Mechanics” and “Automatic file check and clip reloading”.

Edit your Windows Power Options and disable any HDD sleep mechanics.

GPU as Bottleneck

Since all rendering and decoding processes of PLAYDECK are executed on the GPU, a powerful graphics card is indispensable. PLAYDECK has been developed for NVIDIA graphic cards. It is very unlikely, that you get a good performance out of the CPU alone.

Also make sure, that your NVIDIA is the default graphics adapter in the system. You may have an Intel Onboard GPU. In this case, open the NVIDIA Control Panel, select “Manage 3D settings”. In the “Global Settings” Tab you set “Preferred graphics processor” to “High-performance NVIDIA processor”.

Please always use the latest NVIDIA driver.

CPU as Bottleneck

Lets assume, you have a powerfull GPU and the CPU usage % in PLAYDECK isnt rising above 70%. This still does not mean, that your CPU isnt clipping. It could be, that not all CPU cores are used.

Watch your CPU cores carefully in the task manager, while playing the glitching clip. Maybe one CPU core is clipped at 100%, while other cores are barely being used. This phenomenon is called “CPU parking”. Check, if the CPU usage goes UP, if you DONT play any clips. This indicates, that the CPU cores are been parked, because there is less activity. Here is some information on how to proceed:
https://ostoday.org/windows/how-to-unpark-cores-windows-10.html

Watch out for specific processes in the task manager, which have sudden CPU spikes and disable those processes. One known process is “Antimalware Service Executable”, which is the Windows Defender:
https://blog.emsisoft.com/en/28620/antimalware-service-executable/

Also check the energy settings and make sure, that everything is set to “High performance”.

Decklink (or other) Ouput card as Bottleneck

Since the frame rate control is handed over to the decklink device, once it has been activated, the device itself may cause the glitch and not the system. There are some cases, where customers had installed the decklink to a shared PCI slot, where bandwidth would be reduced. We recommend switching the production format to PAL for testing purposes and watch, if the glitches still appear. You could even deactivate the decklink completly and do a testrun.

Please also use the latest driver for your hardware. Some hardware even require you to apply firmware updates.

Other Apps as bottleneck

Other applications may use the harddisk, or network, or GPU/CPU. This may not be recognized as GPU/CPU peak, because the app produces only a very short burst/bottleneck. This is harder to detect. Especially if your clips run smooth most of the time and sometimes/rarely glitch or drop only few frames.

Disable any other applications, that might interfere with the clips you are playing. This would most likely to be Anti-Virus/Malware software.

Also try to create a new user within Windows and start PLAYDECK with the user, who has no administration rights. This might block other apps from interfering.

Other Hardware related bottlenecks

Sometimes you might not even realize, that even the power unit of a system can bottleneck the playout. This is especially true, even you use a powerfull graphics card and another playout card (e.g. Decklink), but only provide, lets say only 600W power, which most certainly isnt enough and would cause the graphics card to cause stuttering (especially on the start of the clip, when power is drawn).

If using several video adapters, a good airflow is also very important to prevent overheating of components, which most likely result in glitches happening more later than sooner.

You can use this Bottleneck Tester to see, if any of your components is underperforming:
https://pc-builds.com/calculator/