| Daala | |
|---|---|
 | |
| Filename extension | .ogv |
| Internet media type | video/ogg |
| Developed by | Xiph.Org,Mozilla,IETF |
| Type of format | Compressed Video |
| Contained by | Ogg |
| Extended to | AV1 |
| Open format? | Yes |
| Website | xiph |
Daala is avideo coding format under development by theXiph.Org Foundation under the lead of Timothy B. Terriberry mainly sponsored by theMozilla Corporation.[1] LikeTheora andOpus, Daala is available free of any royalties and its reference implementation is being developed asfree and open-source software. The name is taken from the fictional character ofAdmiral Natasi Daala from theStar Wars universe.
Thereference implementation is written inC and published, together with itssource code, asfree software under the terms of aBSD-like license.Software patents are being filed for techniques used in and developed for Daala. Those patents are freely licensed to everybody to use for any purpose.[2] However, the patent holders reserve the right to use them to counter patent infringement lawsuits filed by others.
Since June 20, 2013, the development is accompanied by a series of sporadically published posts on the underlying technology on the website of the Xiph.Org Foundation.[3][4][5] The Daala project is one of the collaborators in theIETF'sNETVC project.
Daala is aimed to be a suitable proposal for a new video coding standard for theInternet andreal-time applications.Therefore, it is meant to be usable free frompatent licensing constraints and to be openly documented to enable widespread adoption.[6] Also, it is being designed to cover a broad spectrum of use cases.
Daala was projected to eventually perform as well as if not better than other modern formats. The developers want to rely less on improving traditional design principles incrementally as such effort is observed to deliver decreasing returns after many years, and tends to grow complexity. (All widely adopted designs to date share the same basic design that dates back toH.261 from three decades ago.)[7] Instead, the higher risk of researching and trying new basic techniques is expected to yield unprecedented and potentially more useful algorithms. Such an approach also makes software patent infringement less likely.
Moreover, possibilities for parallel processing are considered and hardware support[8] is being pursued.
Daala is intended to be a high-efficiency video coding format for use cases similar to those ofHigh Efficiency Video Coding (HEVC or H.265) andVP9.[9]It has been stated that the performance goal is to be a generation beyond HEVC and VP9.[10]
As a basic technology Daala uses an unconventionaldiscrete cosine transform with overlapping blocks. This reduces theblocking artifacts characteristic of other video codecs that use thediscrete cosine transform (DCT) directly, without the need foradditional filtering against blocking artifacts.[11]
The coefficients are coded byPerceptual Vector Quantisation (PVQ, a sphericalvector quantisation), which models human perception.
All substreams that the encoder produces are coded to one bitstream by arange encoder.
Within the family of Xiph.Org multimedia formats, Daala is the successor toTheora from 2004.[6] Problems with agreeing on video formats forWebRTC and successes in the development of the audio coding standardOpus are being cited as motivations for developing a video coding standard.[6] Following up on the successful standardisation of Opus at theInternet Engineering Task Force (IETF), it was planned to also develop a worldwide video coding standard there.[6] The purpose of Daala is to provide an initial proposal for the development of that standard. Therefore, it is hoped to be transformed by or reassembled with a lot of useful contributions by other parties.
First experimental code already existed in 2010.[12]First steps in moving from merely investigating coding techniques to having a functional prototype were planned to start on May 27, 2013.[13]On May 30 analpha prototype of Daala was used tostream video over the Internet.[3]
On September 17, 2014, it was generally stated that it could produce better results than its peers up to about 0.5 bits per pixel.[14]
According to Timothy Terriberry, another year of development is needed as of January 2015.[15]
After several preliminary meetings, a respective working group with the mission to develop an Internet Video Codec (NetVC) officially commenced activity on May 18, 2015.[16]Among other contributions, a series of coding techniques from Daala were officially proposed to the group.[17]
On September 1, 2015, Mozilla announced that theAlliance for Open Media would use elements of Daala to develop a royalty free video format,AOMedia Video 1.[18][19][20]
On March 24, 2015, Daala was presented to the IETF as a candidate for their Internet Video Codec (NETVC) video standard.[6][21][22] Daala coding techniques have been proposed to the IETF for inclusion into NETVC.[17]
