FORMAT



Cinema DNG

CinemaDNG (Cinema Digital Negative) is an opened standard for video rawdata by Adobe.

Introduction

CinemaDNG (Cinema Digital Negative) is the result of an Adobe-led initiative to define an open, freely-usable standard for video raw data. Adobe submitted DNG 2007 as a standard file format to the International Standards Organization (ISO).
It is based on the concept of a digital negative and is a file format suitable for storing raw digital camera information.

CinemaDNG can contain directories for video and audio data (including multichannel), metadata and 3D. Requirements for the Digital Negative DNG, TIFF, XMP, and / or MXF in these directories are specified.
To encode the individual images of the video clips, CinemaDNG uses the DNG already familiar from still photography, where the image sequences are either "frame" -based packaged in an MXF file or stored as a sequence of DNG image files in a file directory.

Basics DNG

By and large, there are three types of DNG files: in-camera, converted DNG / RAW files, and converted DNG, linear.

1. In-Camera DNG

Some camera manufacturers have adopted the DNG format as their own camera raw format.

2. Converted DNG file, RAW

When you create a DNG file from a RAW file, you usually have the ability to take the original raw image data lossless.

3. Converted DNG, linear

It is also possible to save a DNG, with part of the file being processed externally. This is called linear DNG. These can be helpful for improved compatibility. It is also possible to convert a JPEG or TIFF format to DNG, creating a linear DNG file.

To understand DNG, it is helpful to compare it with a camera raw file. There are some similarities and some important differences.

Similarities

Camera RAW files are typically a variant of the TIFF / EP format, which is a TIFF file designed specifically for electronic photography. The basic file structure is the same.

Both DNG and RAW data can store the raw image data of your camera.

Both Raw and DNG can save a full-color JPEG version of your raw file. This allows the image to be easily previewed.

RAW and DNG can each store metadata.

Differences

While RAW and DNG are similar in structure, DNG has a well-documented and published file specification. This openly documented structure also makes it possible to use DNG in third-party software.
Most proprietary RAW files are not documented. This means that any software not specifically licensed for a format may also damage the raw data information during editing.

As imaging technology evolves, new software features may become incompatible with legacy software. DNG predicted this and used version compatibility tags to manage the process.

It is possible to store almost any kind and any amount of metadata in a DNG file. That way, you can easily label your images by topic, ownership and license information, and other useful information.

DNG has a very robust metadata storage feature. This means that the settings you use to render your images can be embedded in the DNG file for added security and portability. You can even save multiple sets of settings or settings from more than one program.

DNG Anticipates Imaging Requirements - The DNG specification has a very robust "tag" structure that allows for the orderly storage of all types of image processing data. These tags anticipate new developments in image processing, often long before software is needed.

DNG enables embedded profiles - All raw files must be decoded with a color profile to convert the raw data to standard colors. The DNG specification requires that at least one color profile is embedded in the file. This allows a long decoding of the file. In addition to standard Adobe profiles, DNG provides storage for custom camera profiles and third-party profiles.

DNG allows you to embed rendered versions - While proprietary raw files have an embedded JPEG preview format, this file generally can not be updated because the file is edited. This means that the original version will be previewed, not the version after it has been optimized. Because the DNG structure is openly documented, it is easily possible to embed an optimized version of the file. The specification even allows multiple versions to be embedded.

DNG has an embedded verification tool. This is especially important for long-term archiving. There is an embedded checksum in the DNG file to help you determine if the RAW image has been damaged in any way. In this way, the state of a very large image collection can be easily checked automatically.

The embedded checksum

One of the most valuable features of DNG is the embedded checksum - a tool that allows you to verify the integrity of the image data at any point in the life of the file. In this way, the data validation is performed even if the file has been edited and the metadata has been reinserted into the file.

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