Advanced Video Codec High Definition

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AVCHD (Advanced Video Codec High Definition) is a high-definition recording format introduced by Sony and Panasonic mid-2006. It can use various storage media, including 8 cm recordable DVD discs, a hard disk, or flash memory cards. The format competes with other handheld video camera recording formats, particularly HDV and MiniDV.

1 Technical details
2 AVCHD Controversy
3 Hardware Products
4 Software Products
- 4.1 Video Editing software that supports the AVCHD format:
- 4.2 Software that converts the AVCHD format to other formats:
5 References
6 External links

[edit] Technical details

As its name implies, AVCHD uses an MPEG-4 AVC (H.264) video codec. AVC's better compression (compared to the older MPEG-2 codec, HDV) lets a user record video at the same quality of MPEG-2 but in less space. The audio track can be stored as uncompressed 7.1 linear PCM or compressed AC-3 5.1. The compressed audio and video data are encapsulated in an MPEG-2 Transport stream called BDAV. This stream format and most of the structure of AVCHD are derived from the Blu-ray Disc BDMV format. Consequently, AVCHD recordings can be played without modification in most set-top Blu-ray Disc players, such as the Sony BDP-S1, Panasonic DMP-BD10, and the PlayStation 3.

AVCHD supports a variety of resolutions and aspect ratios, all the way from 480/60i to 1080/24p "Full HD" with 1920x1080 pixels in 16:9 aspect ratio. The typical maximum bit rate for HD recordings is ~24 Mbps when recording to hard disk or flash memory and ~18 Mbps for when recording to DVD. This results in 3 MB or 2.25 MB used per second respectively. (This is about 6 minutes of recording for every GB of storage)

Sony claims the format has a total storage time on a MiniDVD of about 20 minutes of high-definition video using "average" bitrates. By comparison, today's 8 cm discs can store 30 minutes of standard-definition MPEG-2 video, and MiniDV tapes can store a full 60 minutes of either standard-definition DV or high-definition (HDV) video. At the maximum resolution, a standard 8cm DVD will hold just 15 minutes of material. The newer dual layer disks will hold 27 minutes. AVCHD camcorders using hard disks or flash memory such as SD or MemoryStick overcome this constraint and typically offer USB connections to access their content.

Among the touted advantages of AVCHD over MiniDV tapes is random access, since AVCHD does not need to be fast-forwarded or rewound as on tape formats such as MiniDV. For advanced users, however, digital video-footage is rarely edited in-camera anyway; instead, it is transferred entirely to a computer, where the operator uses video editing software. Consequently, random access is less important to some professional users but may prove valuable to professionals in electronic news gathering.

The biggest problem with editing and converting these files is the sheer amount of resources they require—decoding and re-encoding AVC is much more intensive than, say, MPEG-2. Furthermore, AVCHD employs long-GOP frame storage, which while space-efficient, introduces problems into editing and decoding of material. Even so, just as MPEG-2 was originally taxing to home PCs, even needing special PCI decoder cards, AVC's challenges will be overcome with time, especially on multi-core CPUs.

[edit] AVCHD Controversy

Not all manufacturers or consumers accept AVCHD's reasons for existence. The disbelief in AVCHD format is partly encouraged by camcorder manufacturers. So far there is no equipment that utilizes full 24Mbps potential of AVCHD. Instead of using bitrates comparable to HDV and achieving better video quality, the camcorder manufacturers use reduced bitrates (~12Mpbs to ~16Mbps). Most reviewers agree, that while the resulting video quality is comparable to HDV, it is still inferior.^[1]

The lower bitrate makes sense for DVD-based camcorders as well as for solid-state camcorders. Both type of media are limited in capacity and write speed. A single-layer mini-DVD holds only 1.4GB of data, which translates into 15 minutes of video at 12Mbps. The solid-state camcorders are limited by the write speed of a memory card. Presently there are three classes of Secure Digital High-Capacity cards: Class 2 (2 MB/s or 16 Mbps), Class 4 (4 MB/s or 32 Mbps) and Class 6 (6 MB/s or 48 Mbps). Using low bitrate in card-based camcorders ensures that even a slowest memory card has enough throughput for recording video without skipping frames.

There is less practical sense for using lower bitrates in case of HDD-based camcorders, which are routinely equipped with 30GB or 40GB hard drives. There are even models that boast 100GB hard drives. Realizing that file size is not an issue, JVC is marketing the HDD-based GZ-HD7 camcorder, which has 60GB HDD and records in three different types of high-definition MPEG-2 format. One of these types can be loosely called "HDV on disk".^[2] Such equipment preserves compatibility with the proven HDV format, while giving an opportunity for recording onto a hard drive instead of tape.

Another controversial topic is AVCHD compatibility with high-definition players and its role in the HD optical disc format war. Currently available HD-DVD players are not capable of reproducing AVCHD content. On the contrary, Blu-Ray players accept AVCHD video without re-encoding. Further, it is possible to author and distribute high-definition material using readily available and inexpensive DVD disks. The playback time is limited to about 30 minutes, which is enough for amateur video or for business presentations.

[edit] Hardware Products

Sony has released several AVCHD camcorders, the HDR-UX1, UX3/UX5, and UX7 (with recordable MiniDVD and xvYCC recording (no xvYCC on the UX1 and SR1 models), and the HDR-SR1 (with 30 GB hard disk) available since September and October 2006, respectively. In addition, Sony's HDR-SR5 (with 40 GB hard disk), and the HDR-SR7 (with 60 GB hard disk) were released on June 20 2007, followed by the HDR-SR5C and the HDR-SR8 (both with upgraded 100 GB hard disk) a month later. The HDR-CX7 was also released in the summer of 2007 and is flash based, storing video on Memory Stick Duo cards.

Panasonic has released five AVCHD camcorders, the HDC-SD1 (with SDHC), the HDC-DX1 (with recordable MiniDVD), the HDC-SD3, the AG-HSC1U (with portable 40 GB hard disk and SDHC), and the HDC-SD5 and HDC-SD7 (world's smallest HD camcorder, both with SDHC). The HDC-SD3 is available in Japan and offers full 1920x1080 (interlaced) video capture.

Canon has released the HR10 (with recordable MiniDVD), its first AVCHD camcorder, and the HG10 which features a 40 GB hard drive. Both cameras have the similar optics and imager as the tape-based HV20 camcorder.

Panasonic is also working on a professional version of AVCHD called AVC-Intra found on the AJ-HPX2000.

Other companies may be releasing AVCHD camcorders too. However, a trend is emerging towards using ISO standard MPEG-4 AVC/H.264 (.MP4), which is likely to be more attractive to companies like Toshiba, as they support the HD-DVD standard.

Samsung has now released its first (memory card/flash based) high definition camcorder, the SC-HMX10[1]. Instead of using AVCHD, it uses H.264, MP4.

Sanyo has also released a non-AVCHD, 1080i, flashed based camcorder, the Xacti DMX-HD1000[2] which uses ISO standard MPEG-4 AVC/H.264 (.MP4).

[edit] Software Products

[edit] Video Editing software that supports the AVCHD format:

Apple's Final Cut Express 4, Final Cut 6.01, CyberLink's PowerDirector 6, Sony Vegas 7.0e, Vegas Pro 8, and Vegas Movie Studio Platinum 8, Corel's Ulead VideoStudio 11 Plus, Pinnacle's Studio Plus 11, and Avid Xpress Pro and Avid Media Composer, Canopus' EDIUS Pro 4.5.
Nero 7 Ultra Edition Enhanced and Nero 8 Ultra Edition are a software suites which contains the AVCHD editor, found in Nero Vision. Also included in this suite is Nero Showtime, which plays AVCHD files natively. Edited video can also be burned to DVD discs in AVCHD format for playback on hardware players or in Blu-ray format.
iMovie '08 allows you to convert AVCHD to the Apple Intermediate Codec format, but does not support AVCHD directly.
Other developers have pledged their support but it may still take some time for the implementation.

[edit] Software that converts the AVCHD format to other formats:

Canopus's AVCHD Converter can convert AVCHD clips into a format which can be edited using Canopus' EDIUS 3/4.
A related tool, Canopus' ProCoder, can perform conversions that produce files which are usable by other video editing applications that do not support AVCHD natively.
Cineform also offers the Neo HDV product that allows AVCHD clips to be converted into I-frame wavelet .avi files designed for editing and post-production. These .avi files can be accepted by many popular consumer non-linear video editors, including those from Sony, Adobe and Corel, which has acquired Ulead.
Another useful product is CoreAVC, a reasonably cheap and quick h.264 decoder for Windows, which can decode AVCHD as well as a variety of other h.264 formats.
Nero Vision can convert AVCHD files to other formats such as MPEG-2 or AVI and can import them for use in video editing projects. Nero Vision can also export Sony's M2TS format to MPEG-4 files that can be viewed by Quicktime 7.
PowerDVD Ultra comes with an AVCHD codec that can be used with AVISynth [3] and VirtualDubMod [4] as described here[5].

[edit] References

[edit] External links

v • d • e

Industrial & home video media

Magnetic tape

Analog

VERA (1952) • 2 inch Quadruplex videotape (1956) • 1 inch type A videotape (1965) • 1/4 inch Akai (1967) • U-matic (1969) • EIAJ-1 (1969) • Cartrivision (1972) • Video Cassette Recording (aka VCR) (1972) • V-Cord (1974) • VX (aka "The Great Time Machine") (1974) • Betamax (1975) • IVC 2 inch Helical scan (1975) - 1 inch type B videotape (1976) • 1 inch type C videotape (1976) • VHS (1976) • VK (1977) • SVR (1979) • Video 2000 (1980) • CVC (1980) • VHS-C (1982) • M (1982) • Betacam (1982) • Video8 (1985) • MII (1986) • S-VHS (1987) • Hi8 (1989) • S-VHS-C (1987) • W-VHS (1994)

Digital

D1 (1986) • D2 (1988) • D3 (1991) • D5 (1994) • Digital Betacam (1993) • DV (1995) • Digital-S (D9) (1995) • DVCPRO (1995) • DVCAM (1996) • HDCAM (1997) • DVCPRO50 (1998) • D-VHS (1998) • Digital8 (1999) • DVCPRO HD (2000) • D6 HDTV VTR (2000) • MicroMV (2001) • HDV (2003)• HDCAM SR (2003)

Optical disc

Analog

Laserdisc (1978) • Laserfilm (1984) • CD Video (1986?)

Digital

VCD (1993) • MovieCD (1995?) • DVD-Video (1995) • MiniDVD • CVD (1998) • SVCD (1998) • FMD (2000) • EVD (2003) • HVD (2004) • FVD (2005) • UMD (2005) • VMD (2006) • HD DVD (2006) • Blu-ray Disc (BD) (2006) • DMD (2006?) • AVCHD (2006) • Tapestry Media (2007) • Total Hi Def (2008) • HVD (TBA) • PH-DVD (TBA) • SVOD (TBA) • Protein-coated disc (TBA) 3D disc (TBA)