Part 1: Factors Affecting Video File Size
First, we should understand the factors that affect video file size before compressing video with the specific software. Simply, to compress video is to adjust the video duration, bit rate, frame rate, resolution and format.
1. Duration of Video Playback
Basically, the time length is the duration of a video playback. You can cut off the unnecessary part to reduce the file size. It is a way to compress video.
There are a variety of video formats, such as MP4, MOV, AVI and WMV. Next, we simply introduce their features.
ASF (Advanced Streaming Format) is the compressed format developed by Microsoft who wants to compete with Real Player for the media streaming market. This format is suitable for the online video to be watched in the real time. With the application of MPEG4 compression algorithm, it can contain well video quality with high compression rate.
WMV (Windows Media Video) is the streaming media format introduced by Microsoft. It is the upgrade of ASF. A WMV video is smaller than that of ASF even though they share with the same quality. Therefore, it is suitable for online playback and transmission.
AVI is the abbreviation for Audio Video Interleave. As the name suggests, it can play video and audio simultaneously. Here are its features: it has good compatibility, high image quality, but its file size is large.
MP4 is a set of standards used for audio and video compression, implemented by the Moving Picture Experts Group (MPEG) under the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). MP4 is mainly used for streaming media, optical discs, voice transmission, video telephony and television broadcasting, etc. Since it can use the narrow bandwidth and frame reconstruction to compress and transmit data, MP4 can output the best image quality with the less data.
MOV is the audio and video format developed by Apple. QuickTime is the media player specifically designed for this format. MOV supports 25-bit colors, various video effects and multiple compatible MIDI audios. Due to such well quality, it is generally used in films.
The video resolution is a parameter used to measure the amount of data in an image. The higher the resolution, the better the video screen. Of course, the file size will be larger. Therefore, you can compress a video by reducing its resolution.
4. Bit Rate and Frame Rate
Bit rate (symbol: bps) is the number of bits that are conveyed or processed per unit of time. The quality will be clearer when it transfer much data in a second. Frame rate (symbol: fps) is the frequency at which the graphics processor display images in a second. If the frame rate is high, the playback will be smooth and clear. However, similar with video resolution, the higher bit rate and frame rate mean the larger video size. You can reduce these two parameters to compress a video. But it is noted that the video screen will be degraded.
After understanding these factors, we recommend you use the Renee Video Editor Pro to compress video.