Video playback is based on the principle of frequent periodic change of still images, called frames. The more often the frames are changed, the smoother the movement of objects captured in the video clip looks. Unlike film cinematography, where the rate is standard at 24 frames per second, digital video can use different values for this parameter. Typically, video files contain the correct frame rate values in their headers. But sometimes, for one reason or another, the frame rate needs to be changed.
Necessary
VirtualDub 1.9.9 is a free video editing software available for download from virtualdub.org
Instructions
Step 1
Open the video file in VirtualDub software. In the menu, click on the "File" item, and then select the "Open video file …" item, or press the Ctrl + O keys. A file selection dialog will be displayed. Go to the directory with the file whose frame rate you want to change. Highlight the file in the list. Click the "Open" button.
Step 2
Open the dialog for changing the video frame rate. Select "Video" from the menu, and then click on "Frame Rate …".
Step 3
Change the frame rate. In the "Video frame rate control" dialog, in the "Source rate adjustment" group of controls, activate the "Change frame rate to (fps):" radio button. The field to the right of the radio button will become editable. Enter the new frame rate in this field. Click the "OK" button.
Step 4
Enable direct copying of the video data stream. To do this, select the "Video" item in the main menu. In the menu that appears, click on the "Direct stream copy" item. In this mode, the video data will not be processed, which will ensure the preservation of the original video quality, as well as greatly increase the file processing speed.
Step 5
Activate the direct copy audio stream mode. In the main menu of the application, click on the "Audio" item. Next select "Direct stream copy". Similar to direct copying of video data, enabling this mode will increase the speed of file processing and allow you to keep the sound in its original quality.
Step 6
Save a copy of the file with the changed frame rate. Click on the "File" menu item, and then on the "Save as AVI …" item, or simply press the F7 key. In the dialog that appears, select the path to save and the name of the copy file. Click the "Save" button. Don't try to overwrite the original file. The program will give an access error.
Step 7
Wait for the end of the recording. Status information during the saving process will be displayed in the "VirtualDub Status" dialog. If you need to interrupt the file generation process, click the "Abort" button.
