|Developed by||Michael Niedermayer (FFmpeg)|
|Initial release||9 June 2003|
|Latest release||Version 3 (FFV1.3)|
|Type of format||Video compression format|
|Contained by||AVI, MKV, MOV, NUT, etc.|
|Website||FFV1 Video Codec Specification|
FFV1, which stands for "FF video codec 1", is a lossless intra-frame video codec. It can use either variable length coding or arithmetic coding for entropy coding. The encoder and decoder are part of the free, open-source library libavcodec in the project FFmpeg since June 2003. FFV1 is also included in ffdshow or LAV Filters, which makes the video codec available to Microsoft Windows application that support system-wide codecs over Video for Windows (VfW) or DirectShow.
For long-term preservation of digital video sustainable container formats as well as audio/video codecs are necessary. There is no consensus to date among the archival community as to which file format or codecs should be used for preservation purposes for digital video, yet the currently proclaimed codecs are Motion JPEG 2000 (lossless) and uncompressed video.
FFV1 has turned out to be a viable addition to that choice. With compression ratios comparable to JPEG 2000 lossless and its lower computing requirements, it is already being used by professional archives as their long-term storage codec.
The "Österreichische Mediathek", Austria's national audio/video archive has developed DVA-Profession, a Free Software solution for archive-suitable mass video digitization, using FFV1 for storing their videos. The City of Vancouver Archives is also using FFV1 (in a Matroska container) for long-term storage, as is Museum Victoria in Australia.
Within the video archiving domain, the interest in FFV1 is increasing, as can be seen in a thread on the AMIA-L mailing list, the PrestoCentre Forum or the Archivematica mailing list. In an interview for The New York Times magazine about "Tips on Archiving Family History", Bertram Lyons from the U.S. Library of Congress says:
"[...] for video, there are many choices when it comes to codecs (the way the bits are encoded/decoded to represent the visual data, e.g., ffv1, H.264, Apple ProRes) [...]"
"FFV1 has many beneficial technical features [...], but adoption rates are relatively low compared with alternatives, for example JPEG2000. [...] But holding back too long only serves to self-perpetuate the status of FFV1. The adoption by Archivematica and the Austrian Mediathek with their active promotion of FFV1 along with others may start to break this vicious circle. This could lead to a virtuous circle of wider take-up, to shared development, to incorporation into commercial products and a host of other benefits for the community."
Applications supporting FFV1
Here is a list of applications known to be able to read and/or write FFV1 video files, either natively or by installing codec packages.
Entries marked with "-" means that they generally only support either encoding or decoding.
The term "built-in" means that the application can handle FFV1 without the necessity to install additional codec packages. Applications that come with FFV1 support out of the box, usually use FFmpeg's or Libav's libraries in order to do so.
The list is far from being complete, and will be augmented over time:
|Adobe Premiere||Yes||Yes||DirectShow (1,2)|
|Media Player Classic||-||Yes||built-in|
|Harmonic ProMedia Carbon||Yes||Yes||DirectShow (1,2)|
|VirtualDub||Yes||Yes||Video for Windows (1)|
|VLC media player||No||Yes||built-in|
|Windows Media Player||Unknown||Yes||DirectShow (1,2)|
FFV1 is not strictly an intra-frame format; despite not using inter-frame prediction, it allows the context model to adapt over multiple frames. This can be useful for compression due to the very large size of the context table, but can be disabled to force the encoder to generate a strictly intra-frame bitstream. As the gained compression seems to decrease with later versions of FFV1 (version 2,3), the use of GOP size greater than "1" might disappear in the future.
During progressive scanning of a frame, the difference between a current pixel and its predicted value, judging by neighboring pixels, is sent to the entropy-coding process. The prediction is done as follows:
- Prediction = Median( Top, Left, Top + Left - TopLeft )
The third value, "Top + Left - TopLeft", is effectively equivalent to applying the top predictor to the current and the left sample, followed by applying the left predictor to the prediction residual of the top predictor.[note 1] This method, also known as the gradient, exploits both horizontal and vertical redundancy. So in simple terms the prediction is the median of the top, left, and gradient prediction methods. For improved performance and simplicity, the edges of the frame are assumed to be zero to avoid special cases. The prediction in encoding and decoding is managed using a ring buffer.
Entropy coding process
The residuals are coded using either variable-length coding or arithmetic coding. Both options use a very large context model. The "small" context model uses (11*11*11+1)/2=666 contexts based on the neighboring values of (Left-TopLeft), (TopLeft-Top), and (Top-TopRight). The "large" context model uses (11*11*5*5*5+1)/2=7563 contexts based on the same values as before, but also (TopTop - Top) and (LeftLeft-Left), where "TopTop" is the pixel two above the current one vertically, and "LeftLeft" is the pixel two to the left of the current one. In arithmetic coding, each "context" actually has 32 sub-contexts used for various portions of coding each residual, resulting in a grand total of 242,016 contexts for the "large" model. The arithmetic coder of FFV1 is very similar to (and based on) that of H.264.
On April 16, 2006, a commit-message by Michael Niedermayer confirmed that the bitstream of FFV1 (version 1) is frozen:
"ffv1 and ffvhuff havnt changed since a long time and noone proposed any changes within 1 month after my warning so they are officially no longer experimental and we will gurantee decodeability of files encoded with the currenzt ffv1/ffvhuff in the future"
- Version 1 (FFV1.1)
- Version 2 (FFV1.2)
Version 2 was an intermediate version, that was never officially released and should not be used for production purpose.
- Version 3 (FFV1.3)
Although its documentation remains incomplete, starting April 2012, efforts are being undertaken in order to improve its documentation. The current version of FFV1's technical specification document can be found on GitHub.
- Because the top and left predictor are both linear, their order can be swapped, so the "Top + Left - TopLeft" predictor is also equivalent to first applying the left predictor to the current and the top sample, followed by applying the top predictor to the prediction residual of the left predictor.
- "Repository history of FFV1's sourcecode in FFMPEG repository". Michael Niedermayer. Retrieved 21 October 2010.
- "Formats and codecs for digital video preservation (Guideline 22)". NSW State Records. August 2013. Retrieved 10 November 2013.
- "Motion JPEG 2000 at digitalpreservation.gov". U.S. Library of Congress. Retrieved 6 March 2013.
- Fleischhauer, Carl; Frost, Hannah; Beard, Isaiah (November 2010). "AMIA/IASA 2010 - Wrappers and Codecs: A Survey of Selection Strategies". AMIA/IASA. Retrieved 6 October 2013.
- "FFV1 at digitalpreservation.gov". U.S. Library of Congress. 29 May 2012. Retrieved 10 November 2013.
- "Matroska video container information at digitalpreservation.gov". U.S. Library of Congress. Retrieved 10 May 2012.
- "A City of Vancouver Archives' blog post mentioning their use of FFV1". City of Vancouver Archives. Retrieved 10 May 2012.
- "FFV1 discussion on AMIA-L mailing list". Association of Moving Image Archivists (AMIA). December 2012. Retrieved 6 March 2013.
- "Digital master archive format". PrestoCentre Forums. 26 October 2012. Retrieved 6 March 2013.
- "FFV1 vs other formats for preservation". Archivematica mailing list. 24 September 2012. Retrieved 6 March 2013.
- "Digital film archiving in big scale". Archivematica mailing list. 29 January 2013. Retrieved 6 March 2013.
- Lyons, Bertram (2013). "Ask an Expert: Tips on Archiving Family History, Part 3". The New York Times Magazine (online) (The New York Times).
- Addis, Matthew (2013). "Crossing the Chasm (From Research Results to Sustainable Tools and Services for AV)". AV Insider Magazine (PrestoCentre) (#3): p14–15.
- "Company announcement confirming FFV1 support". NOA Audio Solutions. 10 July 2013. Retrieved 29 August 2013.
- "Blender v2.6 Manual: Render/Output/Video". Blender Foundation. 18 November 2011. Retrieved 4 August 2013.
- "Message on FFmpeg developer mailing list about the impact of GOP size parameter of FFV1". Retrieved 10 May 2012.
- "Repository commit message: Bitstream FFV1.1 frozen". Michael Niedermayer. 14 April 2006. Retrieved 8 May 2012.
- "Repository commit message". Michael Niedermayer. 22 March 2010. Retrieved 21 October 2010.
- "Mailing list post: Bitstream FFV1.3 frozen". Michael Niedermayer. 3 August 2013. Retrieved 29 August 2013.
- "Repository commit message: FFV1.3 released as stable". Michael Niedermayer. 26 August 2013. Retrieved 29 August 2013.
- Source code of FFV1 codec for libavcodec — Git access
- Technical Description of the FFV1 Video Codec
- Comparison of different lossless video codecs (2007)