Conversion options

Conversion engine

Although all files can be converted by open-source projects, we reserved some conversions performed by the formats' developers' official software. For example, your Word, Excel or PowerPoint files will be converted by Microsoft Office Word, Excel or PowerPoint software by default. If the "Always use open-source projects to convert documents" option is checked, your files will be converted by LibreOffice software instead of Microsoft Office.

Image quality

Image quality ranges from 1 (lowest image quality and highest compression) to 100 (best quality but least effective compression). If this value is blank, the converter will use the estimated quality of your input image if it can be determined, otherwise 92. When the quality is greater than 90, then the chroma channels are not downsampled. This option only works on a few image formats such as JPG, WEBP, AVIF or PNG etc. For the MNG and PNG image formats, the image quality value sets the zlib compression level (image quality / 10) and filter-type (image quality % 10).

Image size

The output image will keep the resolution (number of pixels per real world length) of the input image by default. If "Change width and height" option is selected, the converter will force to ignore the aspect ratio and distort the input image so it generates an output image exactly the size specified. If "Preserve original aspect ratio" option is checked, the input image will not be squashed or squeezed, only resized.

Video size

Set video frame size. Frame Size describes the size of a single video frame: width x height, measured in pixels. For example: 480p (640 x 480), 720p (1080 x 720) or 1080p (1920 x 1080). The converter keeps the frame size of input video by default, you can manually enter width and height by selecting "Customize video size" option.

Video bitrate

Video bitrate is the number of bits per second. The symbol is bit/s. It generally determines the size and quality of video and audio files: the higher the bitrate, the better the quality, and the larger the file size because of File size = bitrate (kilobits per second) x duration. In most cases, 1 byte per second (1 B/s) corresponds to 8 bit/s.

Video frame rate

Video frame rate tells you how many frames per second there are when recording or playing video. Video cameras in Europe use 25 frames per second (fps). In USA & Japan 29.97fps or 30fps is used. Animators often work with a lower frame rate (e.g. 12fps) so less frames are needed for the same length video clip. If you change the frame rate of a 12fps video clip to 25fps, e.g. by adding it to a 25fps editing project, each frame will be repeated to keep the clip the same duration.

Video aspect

Set the video frame aspect ratio. Frame aspect ratio describes the relationship between the width and height of a single video frame. Typical frame aspect ratios for video are "4:3 (1.3333)" and "16:9 (1.7777)".

Mute

If "Remove all audio streams" option is checked, all audio streams will be removed from the video file. This usually significantly reduces video file size.

Audio bitrate

Audio bitrate is the term used to describe the amount of data being transferred into audio. A higher bitrate generally means better audio quality. For music, 64k (AAC)/96k (MP3) kbps is a good general-purpose setting that will sound good most listeners. This is the standard bitrate for podcasts, and it sounds great on most contemporary devices, including smart speakers and mobile devices.

Sample rate

The Sample rate refers to the number of samples of audio recorded every second. It is measured in samples per second or Hertz (abbreviated as Hz or kHz, with one kHz being 1000 Hz). The most common audio sample rate you'll see is 44.1 kHz, or 44,100 samples per second. This is the standard for most consumer audio, used for formats like CDs. 48 kHz is another common audio sample rate. The higher sample rate technically leads to more measurements per second and a closer recreation of the original audio, so 48 kHz is often used in "professional audio" contexts more than music contexts. For instance, it's the standard sample rate in audio for video.