Random Freeze Frames in Movie or Film Video Due To Conversion Error

Yesterday at QC Central we were doing a QC report for a movie on a UHD SDR Pro-Res File. I immediately noticed a slightly choppy motion to the action. As an inspection I started going frame by frame though the video. on the 4th frame the video froze, meaning it was the exact same frame as the previous frame, this is known as a freeze frame.

Sometimes a freeze frame will occur as a one off occurrence, in which it is just be one, other times there will be what appears to be random freeze frames, but they will often come in a pattern. Sometimes there will be one freeze frame every 4th or 5th frame. There might also be freeze frames that appear in as 3:2 pull down configuration in which there will be 3 frames of action followed by 2 freeze frames.

These random or patterned freeze frames usually occur due to what is known as conversion error. When this situation occurs it is usually from a video that was converted from a different time code. Distributors or networks will often demand a specific time code for the project, often 23.976 frames per second. If the footage was shot in a different time code (or if different cameras on the shoot were shooting at different time codes the footage will have to be converted.

The Freeze frames happen during the conversion when a software based conversion is used. (such as a computer editing program) In order to do time code conversions properly a hardware conversion must be performed using equipment that most post facilities possess. The two main brands are the Teranex, or the Alchemist. These are also available for purchase.

If your QC is rejected for freeze frames and they must be fixed the video will have to be re-converted using a hardware conversion, this will remove the random freeze frames that were induced in the initial conversion. Please contact us if you would like more information.