Hey TwentyStudios,

Thanks for the feedback. We are recording in 1080p Filmscan 1 quality.

I am going to go forward and proceed with some tests.. and also try setting Real-Time Priority in the task manager.

However as far as internal PC recording goes (which is a very convenient / viable thing to do), I am still missing a "Consistent timing with frame dropping if needed" flag in the recording settings, as timing accuracy is critical for our studio environment.. because without this we are just waiting for an accidental PC processing glitch to throw the timing off, no matter how light the environment is (Windows starts a random process in the background etc.)

Is Aximmetry using ffmpeg for encoding video? If so, couldn't a " -vsync drop " parameter potentially fix the issue?

If so adding custom ffmpeg encoding parameters would be highly appreciated.

Hi Speakerbee,

I attempted to recreate your issue but was unsuccessful.

Please note that Cineform Filmscans heavily utilize your CPU. But even so, if for example, your capture card misses some frames, your recording shouldn't skip any frame:

Nevertheless, this may result in some form of stretching.

If you want to ensure absolute frame accuracy in post-production, it's advisable to use a timecode generator connected to your cameras, and record each timecode with each video:

To accurately reproduce your issue, we would require detailed information about your setup, especially in the Flow Editor of Aximmetry. You can share your compound or even a screenshot of it would help greatly. Please also provide details about the testing setup you used to examine the difference in timings of the recordings and mention any messages you received in the logs of Aximmetry during the recording.

NOTE: The Video Recorder module's Frame Rate pin must be kept in Realtime when you are recording a live production, like your test, more on this here.

Aximmetry does utilize FFmpeg, but that parameter is probably not related at all to the issue if one exists.

Warmest regards,

Thanks for the response Eifert!

This issue happens to us during very simple productions too, throughout multiple machines as well.

Here is a documented case of it happening (let me know if you want moore info)

This project is as simple as possible pretty much:
MOV file input -> Keyer -> Cineform out.

The bottom part is a real quick progress bar.

Running on a 11th gen i7-11700K 3.6 GHz / RTX 4090 Combo

I imported the exported file into the timeline using Davinci Resolve, and synced the footage against the original camera recording (same file that was loaded by Aximmetry)

Frame 1: Sync

2 minutes in: Recording is already stretching.

At 34 minutes we are off by 58 frames! (Over 2 seconds)

Happened all in all with little GPU / CPU utilization, system locked at 25 FPS

For comparison we have been using VMIX (uses FFMPEG too) for many years and honestly we have done productions where the system was super loaded etc., even then we haven't had any timing issues of this nature.
Resolve is also unable to time sync the footage based on waveform information 

So we have to meticulously, manually find the missing frames and move them 1 by 1.. until it matches.

Here is a glitch happening: https://www.youtube.com/watch?v=IagL4GGAzQ0

Looking forward your answer, let me know if you need any more info!

We haven’t experienced any sync issues on our end either. Maybe your hard drive isn’t fast enough to handle the relatively high data throughput of the Cineform codec. That would explain why it’s dropping frames without anything indicating it in Aximmetry. Did you try recording at a lower codec bandwidth option? Did you try other codecs than Cineform? 

Hi Speakerbee,

Thank you for your detailed response.
I could not recreate the issue with a similar setup.

From your description, it seemed that you were engaged in a live production due to the mention of output settings being synchronized to a 25p SDI port and the genlock consideration. However, upon reviewing your Flow Editor setup, I see no Video Input, which led me to infer that your setup might be geared toward post-production.
In such cases, it's possible that the video you're attempting to record already contains inconsistencies, such as deviating from the exact 25 FPS. If possible, I would recommend forwarding the video file to sales@aximmetry.com and referencing this forum post. This will enable us to explore this possibility further.

If your operations are confined to post-production, you could set the Video Recorder module's Frame Rate pin to a fixed frame rate instead of Realtime. This could fix performance-induced irregularities and potentially speed up your video rendering.
Note, that in the case of recording videos or playback of videos, the CPU utilization meter within Aximmetry might not provide the most accurate readings. Nevertheless, the FPS meter should always display correct values.

Additionally, I'm curious to know whether you experience this issue when the Timecode is disconnected. Or when using Timecode during your recordings, have you encountered any specific errors related to Timecode?

Warmest regards,