Video
Converting video from one codex to another such as a film post-production team that converts from an editing format such as Apple ProRes to a distribution format such as H.264.Images
Converting from one image format to another such as a graphics designer who converts from a format used by their image editor to an open format such as JPEG 2000 in order to send a mockup to a client.Audio
Converting between audio codecs. It should be noted that video files also contain audio tracks that have their own codecs. As such it is common for the audio to be converted from one codex to another when you convert video. For example, a sound editor for a film may convert from a production audio codex that contains copious amounts of metadata to a distribution format such as MP4 to build a version of the film that can be distributed.Analog
It is possible to transcode from analog to digital. For example, a film restoration effort that converts from 50mm film to an 8K digital format.Lossy
Lossy transcoding is any encoding that loses information such that the resulting media is lower quality. For example, a photographer who reduces an image from 18 megabytes to 2 megabytes using compression with a lossy JPEG 2000 image as output.Lossless
Lossless transcoding converts from one format to another without any loss of information. For example, a musician who converts from FLAC audio to a sound production format designed to capture more metadata that uses a lossless compression algorithm.Decoding & Re-encoding
The process of transcoding has two distinct phases: decoding into an intermediate lossless format and re-encoding in the target format.Master Copy
When transcoding it is a good practice to retain your original files as a master copy. This is particularly important for transcoding to a lossy format. In the event that a master copy is lost, it is possible to transcode back to a higher quality format but the damage will still be done. For example, a musician who transcodes from FLAC to MP3 and losses their master copy may transcode back from MP3 to FLAC but quality will be reduced.Transrating
Transrating is transcoding into the same media format with a reduced bit rate. For example, transcoding from a 320 kbit/s MP3 to a 128 kbit/s MP3.Trans-sizing
Trans-sizing is transcoding that involves reducing the size of media such as a photographer who reduces images from 8000 pixels in width to 1200 pixels in width for their blog.Transmuxing
Transmuxing is the process of repacking the same video and audio files in a different packaging format. This is not technically considered transcoding. For example, repackaging a 256 kbit/s MP3 into a streaming format without changing the MP3 itself.Streaming
It is common for video streaming services to transcode a source video into multiple formats for delivery to different types of clients such as an 8k television on a fiber connection versus an old mobile phone in an area with slow and expensive mobile services. These formats may include security features that make it difficult for clients to download a copy of the video.Live Streaming
Streaming video in real time often requires conversion of a high quality source version to dozens of distribution formats for different devices and regions. These converted files then need to be distributed to data centers close to audiences using techniques such as a content delivery network. Doing this in near real time requires significant resources such as a cloud platform that can be scaled to use a large number of computers.| Overview: Transcoding | ||
Type | ||
Definition | The process of converting media from one format to another. | |
Related Concepts | ||
