Target Size, CRF, or Bitrate? Choosing Video Compression Settings

Video compression is a tradeoff between file size, visual quality, encoding time, and compatibility. The best setting depends less on the file extension and more on what you need to do with the finished video.

MyVideoCompress provides three rate-control modes because each answers a different question.

Use target size when a service has a file limit

Choose Target size when the result needs to fit under an email attachment, messaging, learning-management, or upload limit. The encoder estimates a total bitrate from the requested size and the video's duration, reserves space for audio and container overhead, then runs a two-pass H.264 encode.

Two-pass encoding first studies the video's complexity and then spends bits where they are most useful. The final size should be close to the target, but it cannot be exact to the byte. MP4 metadata, audio, and encoder behavior all add a small amount of variation. If the requested target leaves too little bitrate for a playable video, MyVideoCompress stops and asks for a larger target instead of producing a misleading result.

The 30%, 50%, 70%, and 90% presets are shortcuts that derive a target from the source file. A larger reduction is not always better: a 90% reduction can be too aggressive for a short, already-compressed clip.

Use CRF when visual quality matters most

Choose Quality (CRF) when there is no strict file-size ceiling. CRF asks the H.264 encoder to maintain a broadly consistent visual quality while allowing the bitrate to rise for complex scenes and fall for simple ones.

Lower CRF values keep more detail and usually create larger files. Higher values compress more aggressively. A middle value is a good starting point, followed by a quick visual check of motion, text, faces, gradients, and dark scenes.

CRF does not promise that the output will be smaller. A source that is already efficiently encoded may stay similar in size—or even grow—at a quality-focused setting. MyVideoCompress reports the actual output size and does not label a larger result as a saving.

Use fixed bitrate for a predictable data rate

Choose Bitrate when a downstream workflow expects a particular video data rate. This can be useful for matching an existing delivery profile or keeping several clips broadly consistent.

A fixed bitrate is not the same as a target file size: duration still determines the total bytes, and audio consumes additional bitrate. For most people with a hard upload limit, target-size mode is the clearer choice.

Resolution and frame rate change the amount of work

Resolution controls how many pixels each frame contains. Reducing a 4K source to 1080p or 720p can save more space than pushing the encoder to preserve every pixel at very low quality. MyVideoCompress preserves the aspect ratio and never upscales a smaller source.

Frame-rate reduction can help high-frame-rate recordings. A 60 fps clip can be reduced to 30 fps when smooth slow motion is not needed. The service will not invent extra frames when the source frame rate is already lower.

Audio is part of the size budget

Speech often remains clear at a lower audio bitrate than music. If the video has no useful sound, removing audio gives the video encoder more of the size budget. When audio is kept, MyVideoCompress outputs AAC inside the MP4 file for broad browser and device compatibility.

A practical starting point

Start with the 50% target-size preset for ordinary sharing. Use CRF when you care more about appearance than a precise limit. Lower the resolution before choosing an extreme reduction, and always preview the downloaded result before deleting the source.

Compression is most successful when the setting matches the destination. The goal is not the smallest possible file—it is the smallest file that still works for its intended use.

Sources and further reading

• FFmpeg codec documentation — encoder, bitrate, and codec options used in video workflows.
• MDN guide to media container formats — browser-oriented details about MP4, WebM, and other containers.