Video Transformation

URL-based parameters to manipulate videos in real-time.

URL Based transformations

Using, you can perform real-time transformations to deliver perfect videos to the end-users. These transformations can be performed by using the URL-based transformation parameters.

        URL-endpoint        transformation   video path                                    

These transformation parameters w-300,h-300 can be added in the URL as path params or as query parameters.


  • Input video upto 300MB in size is supported for transformations. This limit can be adjusted based on your pricing plan.

  • Video transformation happens asynchronously. ImageKit internally polls at a fixed interval of 5 seconds up to 3 times by default, i.e., 15 seconds. If the asset is not prepared by this time, ImageKit gives a 302 and serves the original video. You can change the polling attempt count setting from the dashboard to change this behavior.

Within a few seconds, optimized transformations are generated and stored in our caches. From that point onwards, we will serve the actual transformed video.

Supported codecs for inputs

The following table lists the codecs that ImageKit supports in input for resizing and optimization.

Container formatVideo codecAudio codec


h264, mpeg4, hevc, av1

aac, opus


mpeg4, h264



vp8, vp9, av1



mpeg1video, mpeg2video















Supporting files without mp4 extension

For video transformation and optimization to work, the file extension should be mp4. If your resource doesn't have an mp4 extension, you can add /ik-video.mp4 suffix at the end. ImageKit will ignore that suffix while fetching the original asset from your media library or origin, and video transformation/optimization will work as expected. You can further append /ik-thumbnai.jpg, /ik-master.mpd, /ik-master.m3u8 to generate thumbnail, DASH, and HLS playlist, respectively.


Original asset - (resource has no file extension)

DASH playlist -

Thumbnail -

Simple optimization -


Every new video transformation that has never been done before will contribute toward video processing units using the below definition. Subsequent views of the same video transformation only count towards bandwidth.

Video processing units used depends on output video codec, duration and resolution:

Calculation of units for resolution:

  • 1 second of SD video output = 1 unit

  • 1 second of HD video output = 2 units

  • 1 second of 4K video output = 4 units

  • 1 second of 8K video output = 8 units

  • 1 second of 16K video output = 16 units

Calculation of units for video codec:

  • 1 second of video output in H.264 codec = 1 unit

  • 1 second of video output in VP9 codec = 1 unit

  • 1 second of video output in AV1 codec = 10 units

VPU (Video Processing Unit) usage = Duration (in seconds) x Resolution (in units) x Video Codec (in units)

Special operations:

  • Audio extraction - Using vc-none transformation results in audio output. This operation is equal to processing the input video in SD output resolution for the duration of the output audio.

  • Adaptive bitrate streaming - This operation is equal to processing a 30 seconds SD resolution video. In addition, all generated representations are charged based on requested resolutions.

  • Get thumbnail - This operation is equal to processing a 30 seconds SD resolution video.

We define resolutions in terms of total pixel count as the following.



Less than 921,600 total pixels, i.e., less than 1280 x 720.


Greater than or equal to 1280 x 720 but less than 3840 x 2160.


Greater than or equal to 3840 x 2160 but less than 7680 x 4320.


Greater than or equal to 7680 x 4320 but less than 15360 x 8640.


Greater than or equal to 15360 x 8640.


Here are a few recommendations you should follow while using video API in a live environment.

Eagerly generate transformation

Whether a video is optimized or transformed, a new video(s) is generated and saved internally by ImageKit. This process could take a few seconds, depending on the video duration, output format, and transformation parameters. Therefore, you should eagerly generate the transformation before using the video URL in a live environment to ensure it works as expected. It guarantees that all necessary transformations are prepared and ready to be served. This avoids unnecessary data transfer costs on your origin. You can listen to video webhook events to get updates on asset transformations.

Check assets in Chrome and Safari

ImageKit prepares a webm and mp4 variant of the video to serve optimized video to your users. In a few cases, for specific input videos, the encoding could permanently fail for one or both formats. In this case, you will always get 302 instead of 200. Using such a URL in a live environment would result in repeated transformation attempts. This will unnecessarily increase origin data transfer at your end. To ensure that the video is ready in both formats, always fetch the same URL in both Chrome and Safari.

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