XAVC
XAVC and XAVC S are video compression formats introduced by Sony and registered trademarks that are based on the H.264 / MPEG-4 AVC standard . The formats were introduced in October 2012 and are licensed to other companies by Sony. As a recording format, XAVC has so far only been used by Sony cameras (as of Nov. 2015), but many manufacturers support the format in the processing chain.
variants
There are several variants that differ in the coding effort and in the container format.
- XAVC Intra (XAVC-I): Intra-frame coding in which each image is encoded individually, without reference to previous or subsequent images.
- XAVC Long GOP (XAVC-L): Picture group coding that can include data from other pictures in the coding of each individual picture . This type of coding is much more efficient, but also requires significantly more computing power and storage space during the coding.
- XAVC S (XAVC-S): picture group coding, the data are saved with 8 bits and a color subsampling of 4.2.0 in an MP4 format.
The container format for the XAVC and XAVC-L data stream is MXF , with audio files in the lossless AES3 format. The XAVC-S format is specified for the consumer sector, which uses the MP4 container and records audio data in the AAC or LPCM formats .
specification
Depending on the resolution, the XAVC standard defines various minimum requirements for bit rate , color depth and color subsampling , based on the H.264 profiles and levels .
- 4K : High Profile , Level 4.2 or higher
- HD : Main Profile or High 10 Intra Profile , Level 4 or higher
The color sub-sampling can be used in 4: 2: 0 or 4: 2: 2 take place, but not in 4: 4: 4th The color depth can be 8 or 10 bits, depending on the operating point .
A number of operating points are defined which specify the resolution and the bit rate.
| XAVC Intra | XAVC Long GOP | ||||
|---|---|---|---|---|---|
| resolution | Full name | Abbr. | resolution | Full name | Abbr. |
| 4K (4096 × 2160) |
XAVC 4K Intra Class480 CBG | XAVC-I 4K 480 | 4K | ||
| XAVC 4K Intra Class480 VBR | |||||
| XAVC 4K Intra Class300 CBG | XAVC-I 4K 480 | ||||
| XAVC 4K Intra Class300 VBR | |||||
| QFHD (3840 × 2160) |
XAVC QFHD Intra Class480 CBG | XAVC-I QFHD 480 | QFHD 4: 2: 2 10 bit (future) |
XAVC QFHD Long 422 200 | XAVC-L422 QFHD 200 |
| XAVC QFHD Intra Class480 VBR | XAVC QFHD Long 422 140 | XAVC-L422 QFHD 140 | |||
| XAVC QFHD Intra Class300 CBG | XAVC-I QFHD 300 | QFHD 4: 2: 0 8 bit |
XAVC QFHD Long 150 | XAVC-L QFHD 150 | |
| XAVC QFHD Intra Class300 VBR | XAVC QFHD Long 100 | XAVC-L QFHD 100 | |||
| XAVC QFHD Long 60 | XAVC-L QFHD 60 | ||||
| 2K (2048 × 1080) |
XAVC 2K Intra Class100 CBG | XAVC-I 2K 100 | 2K | ||
| XAVC 2K Intra Class100 VBR | |||||
| HD (1920 × 1080, 1280 × 720) |
XAVC HD Intra Class200 | XAVC-I HD 200 | HD 4: 2: 2 10 bit |
XAVC HD Long422 50 | XAVC-L422 HD 50 |
| XAVC HD Intra Class100 | XAVC-I HD 100 | XAVC HD Long422 35 | XAVC-L422 HD 35 | ||
| XAVC HD Intra Class50 | XAVC-I HD 50 | XAVC HD Long422 25 | XAVC-L422 HD 25 | ||
VBR (Variable Bit Rate) and CBG (Constrained Bytes per GOP) stand for the type of bit rate control , the class for the bit rate in Mbit.
Alternatives
The H.264 standard is supported by most current cameras, whereby mostly only the container format and the bit rate are specified, e.g. B. as "MP4 50MBit". Many manufacturers also give their coding protected names as trademarks, or use one of the industry standards. Here is a brief overview:
- AVCHD Advanced Video Codec High Definition : a format and trademark introduced by Sony and Panasonic that is also based on H.264 and uses an MPEG transport stream .
- CinemaDNG : A manufacturer-independent raw data format that compresses the sensor data without loss.
- DNxHD : an HD intraframe video codec from Avid for video editing in post production.
- MPEG-2 : One of the predecessor formats of H.264.
- ProRes : Video format originally introduced by Apple as a processing or intermediate format with intra-frame coding .
- XF-AVC : Trademark used by Canon in the EOS-C range that is very similar to XAVC and was introduced in 2015. The data stream is encoded with H.264 and delivered in an MXF container.
Individual evidence
- ↑ Sony introduces new XAVC recording format to accelerate 4K development in the professional and consumer markets , Sony. October 30, 2012. Retrieved November 1, 2012.
- ↑ a b http://www.xavc-info.org/ , official Sony XAVC page (accessed on September 2, 2015)
- ↑ XAVC_SpecificationOverview_Rev2_2.pdf (accessed on September 2, 2015)
- ↑ XAVC_Profiles_and_OperatingPoints_110.pdf ( Memento of October 3, 2015 in the Internet Archive ) (accessed on September 2, 2015)
- ↑ XAVC_Naming_per_OperatingPoints.pdf (accessed on September 2, 2015)