About Video Codecs
Within the lifetime of a video production the actual media files being used often pass between several different formats that are best suited for the task at hand. For event production, digital signage, film production and other areas where HD and ultra high resolution video is being used, three of the most commonly used compression formats are H.264, ProRes and HAP.
Supported Video Codecs in VDMX
VDMX uses AVFoundation for playback and encoding of media files, plus support for the HAP codecs.
The most commonly used codecs are:
|HAP||All variations of the HAP codecs are supported for playback and encoding.|
|h.264||Playback and encoding are supported and hardware accelerated when possible.|
|ProRes||Playback and encoding are supported with and without alpha channels. Requires additional install of Apple Pro Video Formats.|
|PhotoJPEG||A legacy codec that still widely supported and commonly used.|
Each of these has pros and cons, and often it is recommended to use the codec that best suits your needs:
- HAP: Optimized for real-time playback, low to good quality, optional alpha channel, medium to large file sizes. Use for smooth playback of HD and ultra-high resolution video files (4k and larger) and to reduce file size when an alpha channel is needed.
- h.264: Smallest file size, low to good quality, fewest number of concurrent movies, maximum specification resolution of 4k. Good codec choice for backup, normal speed playback, mobile device recording, streaming and other low bandwidth situations.
- ProRes: Very good quality, optional alpha channel, medium to large file sizes. Good choice for video editing, archiving and basic high quality playback.
While other codecs may be supported through AVFoundation, we typically suggest using one of these three options whenever possible.
Recommended Codecs for Movie Playback
For movie you will typically get the best performance when using HAP or one of its variations, particularly when playing three or more layers of HD (or larger) video files.
For situations with one or two layers it is okay to use h.264 or ProRes files.
Recommended Codecs for Movie Recording
When using the Movie Recorder plugin in VDMX, depending on the use case the recommended choice for codec can vary.
- Video uploads: For recording videos that are to be used for video uploads (e.g. YouTube, Vimeo, social media), it is usually best to capture to h.264; the small file size is ideal for low bandwidth situations and has a good trade off in quality.
- Live remixing: For live remixing, depending on the playback situation you may want to use HAP, PhotoJPEG, h.264 or ProRes for capture.
- Documentation: For documentation of shows (such as the main output, or a camera feed), the h.264 (low to mid quality) or ProRes (high quality) codecs are the best options.
- Capture of footage to use in editing software: When recording video that will be later used in editing software it is recommended to use ProRes as a high quality intermediate format.
- Alpha channels: If the transparency of the video source being capture needs to be recorded the HAP Alpha, HAP Q Alpha or ProRes 4444 codecs can be used.
- Recording to h.264: Many Macs have hardware encoders for h.264 that are automatically used by VDMX during capture when possible. The caveat is that this will typically provide hardware acceleration for only one or two streams at a time; after that it may fall back on the CPU to encode.
Transcoding Media Files
If you need to change movie files between video codec formats, it is always recommended that you start with the highest quality version available. Additional loss in quality can happen if you transcode media files between different lossy formats. Whenever possible you should keep an archive of your original file exports in their lossless formats.
To convert movie files that are already in an AVFoundation supported format, the free AVF Batch Exporter can be used to transcode to different audio/video formats.
For other video codecs, you can use a toolset such as FFmpeg or QuickTime to either directly transcode into one of the recommended formats, or to convert into an intermediate format that is supported by AVFoundation.
Additional tips for transcoding to HAP can be found on the HAP Video Codecs website.