When in Builder, make sure to check the Estimated Initial and Full Weight of your creative. For each unit variant, these values allow you to monitor the recommended weight at build time.
Creatives use smart loading, so each page is loaded progressively as the user interacts with the creative. For the most efficient use of pre-loading, keep the creative flow linear.
When using platform fonts in your creative, Celtra will subset fonts for most components in order to minimize creative weight.
For user-uploaded (custom) fonts, Celtra will try to subset the provided font. In case subsetting is not available for the custom uploaded font, we will serve the full font file size.
When the creative contains any custom code, the entire creative is excluded from subsetting benefits, because there is no way of determining what has been dynamically defined in text-based components within the custom code. In other words, if any custom code (using Frame, or custom code hosting) is present in your creative, fonts will not be subsetted.
Subsetting is supported for the following components:
Button
Texty
Click here for general information on fonts.
By default, large PNG images that are uploaded to the Assets panel are converted to JPEG, which can significantly decrease the creative's weight without affecting the visual quality of the image. You can always switch them back to PNG with the Image Optimization tool.
Supported image files | PNG, GIF, JPG, and SVG image files.
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For best results | Use PNG or GIF files at 72 dpi, unless your image fills the entire creative, then use JPG. Use PNG files for transparency and Animatey animations. |
Do not use | TIFF files. They are too large and will cause your creatives to load very slowly. |
If your image is superimposed over other content, use PNG with a transparent background.
When you import assets into Builder, they are automatically compressed (85% for JPEG, 256 colors for PNG images). However, we recommend choosing by default the lossless compression option in Builder for general use case.Learn more about image optimization in Builder.
If you need to use Retina sized images, make them twice the size you'll need in the creative before uploading it as an asset. Avoid uploading large images and resizing them in Celtra.
If you need to use an image more than once in a single creative, use it from the assets panel. Don't upload it again.
The recommended specifications for video files are different for the Inline Video component and the Play Video action.
See asset specifications for the Inline Video component.
Video used with the Inline Video component is automatically encoded by Celtra into multiple streams of varying quality. The stream chosen for display is dependent on the device and the environment in which the ad is running. Therefore, you can upload a source video file and not encode it yourself.
We recommend that you upload the highest quality video possible, with a maximum size of 60mb.
Source Video File Specifications:
Accepted video formats: MOV, 3GP, MP4, or WebM.
File size: Up to 60 MB for each upload.
Length: Minimum 3 seconds.
All video content that you upload should be in the MPEG-4 (.mp4) video format.
If you own Adobe Media Encoder, you can download and use this one of the following presets, based on your device:
When preparing video for Celtra, use de-interlacing on .mov source files before compressing to .mp4.
Codec | H.264 |
Profile | Main, level 2.1 (Main@2.1) |
Width | 320 or 360 px |
Height | Dependent on video aspect ratio |
Max. File Size | 10mb |
Frame rate | 15, 25, 30 fps. Use the lowest value that looks acceptable to help reduce file sizes. |
Bit rate | 200-250 kbps. Use the lowest value that looks acceptable to help reduce file sizes. |
Format | MP3 |
Channels | mono |
Bit rate | 32 or 64 kbps. Use the lowest value that looks acceptable to help reduce file sizes. |
Generated video files must be streaming compatible. Some encoders do this by default, others (such as ffmpeg) require you to post-process the files using
qt-faststart.
Codec | H.264 |
Profile | Main, level 2.1 (Main@2.1) |
Dimensions | 640 x 360 px. |
Max. File Size | 10mb |
Frame rate | 15, 25, 30 fps. Use the lowest value that looks acceptable to help reduce file sizes. |
Bit rate | Up to 768kbps, however, between 350 and 500 kbps is usually sufficient. Use the lowest value that looks acceptable to help reduce file sizes. |
Format | MP3 |
Channels | mono |
Bit rate | 32 or 64 kbps. Use the lowest value that looks acceptable to help reduce file sizes. |
Generated video files must be streaming compatible. Some encoders do this by default, others (such as ffmpeg) require you to post-process the files using
qt-faststart.
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