> ## Documentation Index > This page is part of the Image and Video APIs product. Fetch the complete documentation index for Image and Video APIs at: https://cloudinary.com/documentation/llms-image-and-video-apis.txt?referrer=docpage and then use it to discover all relevant pages before exploring further. > If your task extends beyond this product, fetch the top-level index covering all Cloudinary products and topics at: https://cloudinary.com/documentation/llms.txt?referrer=docpage # Conditional transformations Cloudinary supports conditional transformations for videos, where a transformation is only applied if a specified condition is met, for example, if a video's width is greater than 300 pixels, apply a certain transformation. **See also**: [Conditional transformations for images](conditional_transformations). This page covers the condition syntax and the video characteristics and operators you can use. To learn how to apply a transformation when a condition is met, see [Specifying transformations for a condition](using_video_conditional_expressions). For multiple AND/OR conditions and else branches, see [Advanced conditional transformations for video](advanced_video_conditional_expressions). ## Specifying conditions To specify a condition to be met before applying a transformation, use the `if` parameter (also `if` in URLs). The `if` parameter accepts a string value detailing the condition to evaluate, and is specified in the URL in the following format: if\_\\_\\_\ **Where:** * video characteristic: The video parameter representing the characteristic to evaluate, for example `w` (or `width` in SDKs). * `operator`: The comparison operator for the comparison, for example `lt` for 'less than' (or `video characteristic value: A hard coded value to check against, a supported user-defined variable containing a value to check against, or a different video characteristic you want to compare to. For example, if you only want to apply a transformation to non-square videos, you could check if the width characteristic of your video is not equal to its height characteristic: `if_w_ne_h` > **TIP**: > > :title=Tips > * Specify strings for a characteristic sub-element or value surrounded by `! !`. For example, `if_ if_ctx:!productType!_eq_!shoes!`. > * You can check whether a string characteristic currently has no value using `!!`. > For example: `if some-condition_eq_!!` See [examples](using_video_conditional_expressions#conditional_transformation_examples). ### Supported video characteristics Characteristic | Description ---|--- `w` | (also `width` in SDKs) The asset's current width. `iw` | The asset's initial width. `h` | (also `height` in SDKs) The asset's current height. `ih` | The asset's initial height. `ar` | (also `aspect_ratio` in SDKs) The aspect ratio of the asset. The compared value can be either decimal (e.g., 1.5) or a ratio (e.g., 3:4). `iar` | The asset's initial aspect ratio. `ctx` | A contextual metadata value assigned to an asset. `md` | A structured metadata value assigned to an asset. `tags` | The set of tags assigned to the asset. `du` | (also `duration` in SDKs) The current duration of the video. `idu` | The video's initial duration. ### Supported operators URL | SDK symbol | Description ---|---|--- `eq` | `=` | Equal to `ne` | `!=` |Not equal to `lt` | `` |Greater than `lte` | `=` |Greater than or equal to `in`|`nin` | `in`|`nin` | Included in | Not included inCompares a set of strings against another set of strings. See [Using the in and nin operators](#using_the_in_and_nin_operators) for examples. When working with the Cloudinary SDKs, you can specify the condition using the SDK characteristic names and operator symbols, or you can specify it using the URL format. For example, both of the following are valid: * { if: "w\_gt\_1000"},... * { if: "width > 1000"},... #### Using the in and nin operators The `in` and `nin` operators compare two sets of strings. The `:` delimiter between strings denotes **AND**. String sets can include **tags**, **contextual metadata** or **structured metadata** values, for example: * To determine if `sale` and `in_stock` are present in the tags of a particular asset, use: `if_!sale:in_stock!_in_tags`. * To determine if the key named `color` exists in the contextual metadata of a particular asset, use: `if_!color!_in_ctx`. * To determine if a structured metadata field with external ID, `color-id`, has been set for a particular asset, use: `if_!color-id!_in_md`. * To determine if a list value with external ID, `green-id`, has been selected from a multiple-selection structured metadata field with external ID, `colors-id`, for a particular asset, use: `if_!green-id!_in_md:!colors-id!`. ### Supported conditional video transformation parameters and flags * **All video transformation parameters** can be assigned in conditions **except**: * You cannot assign transformation parameters for the `format`, `fetch_format`, `color_space`, `delay`, `video_codec`, `audio_codec`, `start_offset`, `end_offset`, or `duration` parameters. * The `angle` parameter cannot be set to `ignore`. * **Only the following flags** are supported inside conditional video transformations: `layer_apply`, `relative`, `attachment`, `awebp` ### Notes * For the `w`, `h`, and `ar` parameters, the values refer to the current video status in the transformation chain (i.e., if transformations have already been applied to the video), while `iw`, `ih`, `iar` always refer to the original video. * `dpr` is not supported as a conditional transformation with the `ar` characteristic. Additionally, `w` and `h` are supported with `dpr` as long as they are still equal to `iw` or `ih` when the condition is evaluated. If `dpr` is specified in the transformation as a whole, and one of the conditional branches includes a resizing transformation, you need to specify a resize transformation in all the other branches too. * The `ar` (aspect ratio) parameter should be compared using 'greater than' or 'less than' rather than with 'equals'. This is because the width and height values are given as integers and not floating point values, leading to an "almost exact" calculated aspect ratio. * Contextual metadata values are always stored as strings, even if the value is numeric, therefore you cannot use the `lt`, `gt`, `lte` and `gte` operators to compare contextual metadata values numerically. You can, however, use these operators with numeric structured metadata values - [see an example](using_video_conditional_expressions#conditional_image_overlay_based_on_structured_metadata_value). * You can test whether or not a variable has been defined using the parameters `if_isdef_$` and `if_isndef_$` (see [Testing whether a variable has been defined](video_user_defined_variables#testing_whether_a_variable_has_been_defined)). > **READING**: > > * [Specifying transformations for a condition](using_video_conditional_expressions): Learn the syntax for applying transformations when a condition is met, including chained transformations and worked examples. > * [Advanced conditional transformations for video](advanced_video_conditional_expressions): Combine multiple conditions with AND/OR logic and define fallback transformations using else branches.