How to Calculate AVI Overhead
Finding the exact overhead for your AVI file is nearly impossible given all the variables involved. You can calculate a close estimate of the file size necessary to package your AVI file. When encoding a large video with audio content, the AVI container assigns space for the audio to align with each frame of the video. This assignment is the overhead of the AVI. The type of audio and the number of frames in the video will yield the overhead that will be added to the total file size after the audio and video files are muxed.
Other People Are Reading
Instructions
-
-
1
Find the frames per second for your video. Hollywood videos are shot at 24 frames per second. Find the number of frames per second for your audio, which may be one and half to two times the video rate.
-
2
Determine the number of overhead producing units in your AVI file. Each frame of audio and video produces one unit of overhead. Multiply the number of seconds in your video by the number of audio frames. Multiply the same for the video frames, then add the two products. For example, in a 10 minute video you have 600 seconds. If the video is 24 fps and the audio is 48 fps, then you would have 14,400 units of overhead for video and 28,800 for audio for a total of 43,200 units.
-
-
3
Multiply the units by 24 bytes. For example, 43,200 units would give you 1,036,800 bytes. Divide that number by 1,024 to find the number of kilobytes. For example, 1,036,800 bytes is equivalent to 1,012.5KB. Divide by 1,024 again to get the number of megabytes, which would be 0.99MB of AVI overhead.
-
1
Tips & Warnings
These calculations use the rate of 24 bytes per unit of audio that applies to MP3 audio. AC3 audio only uses about nine bytes per frame.
