AVCHD

From Wikipedia, the free encyclopedia

AVCHD (Advanced Video Codec High Definition) is a high-definition recording format for use in digital tapeless camcorders. The format is comparable to other handheld video camera recording formats, particularly TOD, HDV and MiniDV.

Contents 1 History 2 Overview 3 Media 3.1 DVD disks 3.2 Hard disk drives 3.3 Memory cards 4 Compatibility with Blu-ray Disc players 5 Handling interlaced video 6 Hardware Products 6.1 Sony 6.2 Panasonic 6.3 Canon 6.4 JVC 7 Software 7.1 Converting 7.2 Editing 8 Authoring 8.1 Open Source Codecs 9 Specifications 10 See also 11 References 12 External links

[edit] History

In 2003 Sony introduced XDCAM, one of the first professional tapeless video systems. The format used Professional Disc as recording media. The cost of media was comparable to other professional formats that existed at that time, and was prohibitively high for a consumer version of such a camera.

In April 2004 Sony mentioned the possibility of expanding XDCAM format or its variants into consumer market. Rick Clancy, Senior Vice President of Corporate Communications at Sony stated that XDCAM is more of a higher end professional HD product, and future consumer tapeless camcorders would be based on the less expensive Blu-ray format.^[1] Similar to Professional Disc, Blu-ray Disc format is based on blue-violet laser technology, but disks are single-sided, do not have protective cartridge, made of cheaper material and deliver lower data rates.^[2]

In September 2004 Sony augmented Blu-ray Disc specification with AVC and VC-1 video codecs in addition to existing MPEG-2 codec. New codecs provided more efficient compression and allowed using lower data rates, meaning longer movies could be stored on the same disc.^[3]

In May 2006 Panasonic and Sony jointly announced AVCHD as a tapeless high definition recording format. The format was based on existing Blu-ray Disc specification and allowed recording AVC-encoded video onto optical disks. 8 cm DVD disks were chosen as recording media instead of considerably more expensive Blu-ray disks.^[4]

In July 2006 the format was amended to include other types of random-access media, like SD/SDHC memory cards, "Memory Stick" cards and hard disk drives. Blu-ray disks were not included in the list of officially supported media.^[5]

The first AVCHD camcorder, Sony Handycam HDR-UX1, went on sale in September 2006 and used 8 cm DVD media. Panasonic released its two first AVCHD camcorders in spring 2007, the HDC-DX1 used 8 cm DVD media, the HDC-SD1 became the first AVCHD camcorder to record to SD/SDHC solid-state media. Canon supported the new video format with the HR10 that recorded to 8 cm DVD media, and with the HG10 that recorded onto a built-in hard disk drive. Until recently JVC was promoting its own TOD format, but joined AVCHD camp by releasing AVCHD-capable camcorders in April 2008.

See full list of products below.

[edit] Overview

AVCHD (AVC-HD, AVC HD) employs AVC video codec with inter-frame long GOP compression, and AC-3 or PCM audio codec. A wide range of frame sizes and rates, both interlaced and progressive, is supported. Compared to HDV camcorders based on MPEG-2 codec, AVCHD camcorders achieve higher compression and lower data rates with comparable image quality.

The format supports slide shows, subtitles and menu navigation. Slide shows created out of still AVC pictures can be used for high quality image presentation with or without background audio. Subtitles are used in some camcorders to keep track of recording date/time. DVD-like menu navigation makes AVCHD a more attractive format for consumer users.

Audio, video and subtitle streams are encapsulated into MPEG-2 Transport stream and stored on media as binary files. In this regard AVCHD is similar to TOD.

AVCHD directory structure is derived from the Blu-ray Disc specification but is not identical to it. In particular, known AVCHD implementations use old-fashioned "8.3" filename convention, while Blu-ray disks utilize long filenames.

Another notable difference is location of the BDMV folder, which contains media files. On a proper Blu-ray disk and on a DVD-based camcorder the BDMV folder is placed in the root of the disk. On the HDD-based Canon HG10 camcorder the BDMV folder is located in the AVCHD folder, which is placed on the root level.^[6] On the solid-state Panasonic and Canon camcorders the AVCHD folder is nested in the PRIVATE folder.^[7] Following a standard agreed upon by many still camera manufacturers, the solid-state camcorders have a root-level DCIM folder for still images.^[8]

AVCHD media files can be copied to a computer either directly off removable media or by connecting a camera via USB. That means AVCHD files can be transferred to the computer at speeds from 5 to 30 Mbytes per second whereas DV and HDV camcorders are forced to transfer at realtime playback speed of 3.5 Mbytes per second, requiring Firewire connection and specialized capturing software.

A significant issue with editing and converting AVCHD media files is the amount of memory and processing resources required. Decoding and re-encoding AVC is more resource-intensive than similar processing of MPEG-2 video, for example. Even playing back AVCHD video can be impossible on older computers.

However, just as MPEG-2 was originally taxing to home PCs, AVC challenges are being overcome. Improvements in multi-core computing make possible watching and editing AVCHD video on a mainstream desktop computer or even a laptop.

[edit] Media

AVCHD specification allows using several kinds of recording media, in particular recordable DVD disks, memory cards and hard disk drives.

[edit] DVD disks

DVD disks is the original media specified in AVCHD standard. To reduce camcorder size, only smaller 8 cm disks, sometimes called miniDVDs, are allowed. Recording capacity ranges from 1.4 GB for a single-sided single layer disk to 5.2 GB for a double-sided double layer disk.

Pros:

• DVDs are familiar to most consumers, thus considered user-friendly
• Recordable DVDs are relatively cheap
• Recorded disk can be played back in a Blu-ray player
• Disks can be used as immediate backup media, can be stored separately from a camcorder

Cons:

• The longevity of recordable DVDs is argued to be much shorter than expected^[9]
• Rewritable DVDs cost more than write-once disks
• DVDs have to be "closed" to be played back on set-top players
• Recording rate for DVD-based camcorders is limited to 18 Mbit/s
• A single-sided single-layer 8 cm DVD can fit only 15 minutes of video at 12 Mbit/s data rate, 10 minutes at 18 Mbit/s data rate

[edit] Hard disk drives

HDD was added as a possible media to AVCHD specification shortly after the new video standard has been announced. Capacity ranges from 30 GB to 120 GB.

Pros:

• Capacity is enough for several hours of high quality recording
• Allow faster recording data rate up to 24 Mbit/s

Cons:

• Can fail at low atmospheric pressure; most HDD-based camcorders are not allowed to be used at altitudes higher than 10,000 feet (3,000 m)
• Can be damaged from shock or fast movement
• To transfer video to a computer one has to connect the camera with USB cable; other media types do not require presence of the camera to capture recorded video
• Recorded video must be backed up on alternative media as the built-in HDD is not removable

[edit] Memory cards

Memory cards are a promising media for tapeless camcorders. The capacity of memory cards is constantly increasing, while prices are falling. AVCHD supports SD/SDHC memory cards, and "Memory Stick" cards.

Pros:

• Newer high capacity cards can be used in existing equipment
• Memory cards are removable media and can be read in most modern computers
• Not susceptible to low atmospheric pressure like HDDs
• Have no moving parts
• Compact and lightweight
• Rewritable
• Can be easily backed up to DVD disks for viewing on a Blu-ray player and for long-term archiving^[7]
• Some TVs and Blu-ray players have built-in card readers and can play AVCHD video directly off a card

Cons:

• Not all devices support Memory Stick cards; not all devices that support SD cards can read SDHC cards
• More expensive than recordable DVDs
• Can be damaged electrically or broken mechanically
• Not proven for archival purposes
• Class 4 cards or better required for data rates of 16 Mbit/s and faster

[edit] Compatibility with Blu-ray Disc players

Before AVCHD standard has been finalized, end users could master high definition content in Blu-ray format (BDMV) on either BD-R/BD-RE disks or regular DVD disks. At one point Blu-ray Disc Association was considering separating studio content and home-made content using different folders, namely BDMV for studios and HDMV or BDAV for home use. This idea did not seem to get a lot of traction.^[10] Instead, AVCHD is being offered as the means of creating and recording home videos in high definition.

Being creators of AVCHD, Sony and Panasonic are keen to support AVCHD disks in their Blu-ray players. In particular, Sony BDP-S1, Panasonic DMP-BD10, Panasonic DMP-BD30 and the PLAYSTATION 3 computer entertainment system can play AVCHD video recorded onto a DVD disk. PLAYSTATION 3 can also play AVCHD content from connected USB storage devices. Select Panasonic players and television sets are capable of playing AVCHD content off SDHC memory cards.

Not all manufacturers provide reliable AVCHD support in their products. For example, Samsung removed support for both "BDMV on DVD" and "AVCHD on DVD" in a recent firmware release 2.3 for the BD-P1200 player.^[11]

[edit] Handling interlaced video

Despite that AVCHD specification supports 720p progressive recording mode, most AVCHD camcorders released to date record 1080i interlaced video. This creates issues when such video is watched on a computer or when it is rescaled. Computer monitors as well as plasma and LCD televisions are inherently progressive. Watching interlaced video on a progressive display device may produce horizontal ripples known as combing artifacts.

Deinterlacing allows getting rid of combing artifacts, but reduces vertical resolution. Interlaced video can be deinterlaced in post-production and delivered as progressive, or it can be deinterlaced on playback.^[12] All modern flat-panel televisions have a built-in deinterlacing engine. The efficiency of deinterlacing depends on used algorithms and on video itself, video with lots of movement is harder to deinterlace.

There is a technique that allows capturing and transmitting progressive video using interlaced equipment. This technique is borrowed from television industry and has two major flavors depending on whether a particular video system utilizes 50 Hz or 60 Hz scanning.

Progressive segmented frame (PsF) recording scheme originates from 2-2 pulldown technique, which is commonly used in 50 Hz systems to broadcast movies. This scheme is utilized in the Canon HG10 camcorder for 50 Hz market ("PF25" mode, 25 frame/s) and in the Canon HF10/HF100 camcorders for 60 Hz market ("PF30" mode, 30 frame/s). Such a video can be processed with standard interlaced hardware and software, it retains full vertical resolution, scales well and does not require deinterlacing. Currently available Sony AVCHD camcorders do not offer PsF-like recording option, though some older Sony MiniDV models did.

Another approach to package progressive material into interlaced video stream has been borrowed from the 60 Hz television system, which uses 2-3 pulldown to broadcast movies. This recording scheme is meant to add cinematic flavor to interlaced video and is not relevant to 50 Hz systems. Select camcorders from Canon (HG10, HF10, HF100) and from Panasonic (SD9, HDC-SD100, HDC-HS100) are capable of recording 24 frame/s progressive video using this scheme. To achieve full 1080 lines of vertical resolution a display device or an editing system must recognize the pulldown pattern and recover the original frames. This process is known as inverse telecine or film-mode deinterlacing.

[edit] Hardware Products

[edit] Sony

• September 2006: HDR-UX1 (DVD), HDR-UX3/UX5 (DVD), HDR-UX7 (DVD)
• October 2006: HDR-SR1 (30 GB HDD)
• June 2007: HDR-SR5 (40 GB HDD), HDR-SR7 (60 GB HDD)
• July 2007: HDR-SR5C (100 GB HDD), HDR-SR8 (100 GB HDD)
• Summer 2007: HDR-CX7 (Memory Stick Duo)
• March 2008: HDR-SR10 (40GB HDD, Memory Stick), HDR-SR11 (60 GB HDD, Memory Stick), HDR-SR12 (120 GB HDD, Memory Stick)
• HDR-TG1/TG3 (Memory Stick Duo)

[edit] Panasonic

• HDC-DX1 (MiniDVD), HDC-SD1 (SDHC)
• HDC-SD3 (SDHC, available in Japan only)
• AG-HSC1U (SDHC, comes with portable 40 GB HDD storage)
• July 2007: HDC-SD5 (SDHC), HDC-SX5 (MiniDVD, SDHC)^[13]
• HDC-SD7 (SDHC)
• January 2008: HDC-SD9 (SDHC), HDC-HS9 (60 GB HDD, SDHC)^[14]
• April 2008: AG-HMC70 series (SDHC)^[15]
• June 2008: HDC-SD100 (SDHC), HDC-HS100 (60 GB HDD, SDHC)^[16]

[edit] Canon

• HR10 (MiniDVD)
• 2007: HG10 (40 GB HDD)
• April 2008: HF10, HF100 (SDHC)

[edit] JVC

• June 2008: GZ-HD10 (HDD, MicroSDHC), GZ-HD30/GZ-HD40 (HDD, MicroSDHC card, dual AVCHD and TOD recording)

[edit] Software

[edit] Converting

• 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.
• MainConcept sells a codec that is recommended for Adobe Premier users.
• 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 and VirtualDubMod as described here.^[17]
• There is a transcoder to convert AVCHD into P2, which is a format you can import into Avid's MXF file format. The transcoder was created by Main Concept and is distributed free of charge by Panasonic. Version 1.1 and earlier will convert AVCHD media from any camera, while version 1.2 and higher is locked to only work with AVCHD media created with Panasonic cameras. You can download the file from here.
• Latest version VAIO Editing Components that pre-loaded with Sony VAIO PCs can serve as a plug-in for Adobe Premiere Pro 2 to support AVC-HD import/export and editing.
• VoltaicHD is a simple yet useful tool to allow you to convert AVCHD files into other useful formats. The PC version allows output to WMV and AVI but is currently limited to the first 2Gb of any file produced by the camera. A Mac version is also available.

[edit] Editing

The following video-editing software features support for the AVCHD format:

• Corel's Ulead VideoStudio 11 Plus, Corel's Ulead DVD MovieFactory 6, CyberLink's PowerDirector 6, Sony Vegas 7.0e, Vegas Pro 8, and Vegas Movie Studio Platinum 8, Pinnacle's Studio Plus 11 & 12, Avid Xpress Pro and Avid Media Composer, Canopus' EDIUS Pro 4.5.
• Nero 7 Ultra Edition Enhanced and Nero 8 Ultra Edition are 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.
• Apple's Final Cut Express 4, Final Cut 6.0.1, and iMovie '08 (Bundled with all new macs) allow you to convert AVCHD to the Apple Intermediate Codec format, but do not support AVCHD directly.^[18]
• Other developers have pledged their support but it may still take some time for the implementation.

See the comparison of video editing software for more information on these products.

[edit] Authoring

• (Mac) Roxio Toast Titanium 9 is a converting and authoring tool with rudimentary editing functions. It is capable of importing AVCHD video and authoring a DVD, AVCHD or Blu-ray disk. Standard definition authoring is included, high definition authoring requires HD/BD Plug-in, which costs extra.

[edit] Open Source Codecs

The following open source codecs can decode AVCHD files:

• ffdshow tryouts revision 1971 May 23 2008 will decode AVC (H.264) format video. ^[19]

[edit] Specifications

Video
Video signal	1080/60i 1080/50i 1080/24p	720/60p 720/50p 720/24p	480/60i	576/50i
Frame size in pixels	1920×1080 1440×1080	1280 x 720	720×480	720×576
Frame aspect ratio	16:9		4:3, 16:9
Video Compression	MPEG-4 AVC/H.264
Luminance sampling frequency	74.25 MHz 55.7 MHz	74.25 MHz	13.5 MHz	13.5 MHz
Chroma sampling format	4:2:0
Quantization	8 bits (both luminance and chrominance)
Audio
Compression	Dolby Digital (AC-3)		Linear PCM
Compressed audio bitstream rate	64 to 640 kbit/s		1.5 Mbit/s (2 channels)
Audio mode	1-5.1 channels		1-7.1 channels
System
Stream type	MPEG-2 Transport stream
Maximum system data rate	~24 Mbit/s (~18 Mbit/s for DVD)
File extension (generally)	mts (on camcorder), m2ts (after import to computer)
Media	8 cm DVD media, SD/SDHC Memory Card, "Memory Stick", Built-in Media

[edit] See also

• AVCREC: a standard to allow recording AVC encoded, Blu-ray Disc compatible HD content on ordinary DVD discs.
• Comparison of video editing software

[edit] References

1. ^ "Sony plans to eventually release Blu-ray HD camcorder".
2. ^ "Blu-ray FAQ".
3. ^ "Sony is developing 200GB Blu-ray storage".
4. ^ "Panasonic and Sony jointly developed new HD Digital video camera recorder format for recording on disc".
5. ^ "Panasonic and Sony expand AVCHD recorder format".
6. ^ "Canon HG10 AVCHD camcorder video sample".
7. ^ ^{a b} "Backing up AVCHD video onto DVDs and playing them on a Blu-ray player".
8. ^ "KODAK Digital Camera: Navigating to Your Pictures".
9. ^ "DVD Longevity and Reliability".
10. ^ "Doom9.com, AVCHD compatibility testing".
11. ^ "Samsung BDP1200 discussion at avsforum.com".
12. ^ "Watching interlaced video on a computer".
13. ^ "Panasonic introduces two world’s smallest 3CCD Full HD camcorders".
14. ^ "Panasonic unveils two new AVCHD camcorders with new face detection and intelligent shooting guide".
15. ^ "Panasonic ships industry's first professional AVCHD shoulder-mount camcorder".
16. ^ "Panasonic introduces two first AVCHD camcorders with a 3MOS system".
17. ^ How to edit AVCHD M2TS files from Sony HDR-SR1 camcorders
18. ^ Final Cut Express 4 User Manual (Search for AVCHD)
19. ^ [1]

[edit] External links

• AVCHD Official Consortium Web site
• How to Edit AVCHD Files with VirtualDub
• Panasonic DMP-BD10 AVCHD firmware update
• Sony BDP-S1E AVCHD firmware update (for European players with firmware below v3.20)
• Elecard AVCHD batch folder converter
• Voltaic HD Converter for Mac OS X
• RevolverHD for Mac
• Voltaic HD Converter for PC
• Canopus AVCHD Converter Download
• MainConcept AVC codec
• Oxygen AVCHD Player

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