Created attachment 122663 [details] Sample frame SUMMARY If its parameters are animated, the DeFish filter produces very interesting results when rendered with parallel processing enabled. Apparently, the settings get overwritten mid-frame by competing threads, resulting in different zones being rendered with the settings from different frames. STEPS TO REPRODUCE 1. Add a clip to the timeline. 2. Add the DeFish filter to the clip. 3. Set the Type to Stereographic (this probably isn't important to the bug, but it affects the interpretation of the Amount value). 4. Add a key frame to the end of the clip's range. 5. Within the DeFish filter, set the key frame at the start to Amount = 0 and the key frame at the end to Amount = 930. 6. Render the video with Parallel processing enabled and with Threads set to 1. OBSERVED RESULT Frames are rendered with different DeFish filter Amount values for different scanlines. This becomes more noticeable near the end of the animation, when the change in Amount produces a more pronounced change in the distortion. EXPECTED RESULT The rendered video frames should be effectively the same as shown in the preview window, with a smooth change in the distortion over the course of the animation. SOFTWARE/OS VERSIONS Windows: Windows 10 1903 KDE Frameworks Version: 5.61.0 Qt Version: 5.13.0 MLT Version: 6.16.0
Created attachment 122664 [details] Sample frame
Created attachment 122665 [details] Sample frame
Created attachment 122666 [details] Sample frame
Work-around: Disable parallel processing.
Rendering is done via MLT and MLT has problems with parallel processing. So it's an upstream problem Kdenlive cannot solve.
Perhaps it would make sense, then, for Kdenlive to know which filters have this upstream problem and either warn the user or refuse to use parallel processing if the render will be affected.
Hi and thank you for your patience. Can you please check whether this issue still exists in the latest version 24.12.0? If yes, please update this report to reflect the new version and set the status to CONFIRMED. If it works now like you expect it would, you may change the status of this report to RESOLVED - FIXED. At any rate, this report will be closed if there is no activity for the next 30 days.
🐛🧹 ⚠️ This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information, then set the bug status to REPORTED. If there is no change for at least 30 days, it will be automatically closed as RESOLVED WORKSFORME. For more information about our bug triaging procedures, please read https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging. Thank you for helping us make KDE software even better for everyone!
🐛🧹 This bug has been in NEEDSINFO status with no change for at least 30 days. Closing as RESOLVED WORKSFORME.
Sorry for the delay. I repeated by reproduction steps with 24.12.1 and it appears the issue has been fixed. No rendering error occurred. Tried with both 1 and 4 threads with parallel processing enabled. The Resolved state of the bug thus seems to be correct.
Thank you for the feedback