AVCHD

File based format for the digital recording and playback of high definition video

AVCHD (Advanced Video Coding High Definition) is a file based format for the digital recording and playback of high definition video. It is H.264 and Dolby AC 3 packaged into the MPEG transport stream, with a set of constraints designed around the camcorders. Developed jointly by Sony and Panasonic, the format was introduced in 2006 primarily for use in high definition consumer camcorders. Related specifications include the professional variants AVCCAM and NXCAM. Favorable comparisons of AVCHD against HDV and XDCAM EX solidified perception of AVCHD as a format acceptable for professional use. Both Panasonic and Sony released the first consumer AVCHD camcorders in spring of 2007. Panasonic released the first AVCHD camcorder aimed at the professional market in 2008, though it was nothing more than the (by then discontinued) FLASH card consumer model rebadged with a different model number. In 2011 the AVCHD specification was amended to include 1080 line 50 frame/s and 60 frame/s modes (AVCHD Progressive) and stereoscopic video (AVCHD 3D). The new video modes require double the data rate of previous modes. AVCHD and its logo are trademarks of Sony and Panasonic.

For video compression, AVCHD uses the H.264/MPEG 4 AVC standard, supporting a variety of standard, high definition, and stereoscopic (3D) video resolutions. For audio compression, it supports both Dolby AC 3 (Dolby Digital) and uncompressed linear PCM audio. Stereo and multichannel surround (5.1) are both supported. Aside from recorded audio and video, AVCHD includes many user friendly features to improve media presentation: menu navigation, simple slide shows and subtitles. The menu navigation system is similar to DVD video, allowing access to individual videos from a common intro screen. Slide shows are prepared from a sequence of AVC still frames, and can be accompanied by a background audio track. Subtitles are used in some camcorders to timestamp the recordings. Audio, video, subtitle, and ancillary streams are multiplexed into an MPEG transport stream and stored on media as binary files. Usually, memory cards and HDDs use the FAT file system, while optical discs employ UDF or ISO 9660. At the file system level, the structure of AVCHD is derived from the Blu ray Disc specification, but is not identical to it. In particular, it uses legacy "8.3" file naming convention, while Blu ray Discs utilize long filenames (this may be caused by the fact that FAT implementations utilizing long file names are patented by Microsoft and are licensed on a per unit sold basis). Another difference is location of the BDMV directory, which contains media files. On a DVD based camcorder the BDMV directory is placed at the root level, as on the Blu ray Disc. On the HDD based Canon HG10 camcorder the BDMV directory is located in the AVCHD directory, which is placed at the root level. Solid state Panasonic and Canon camcorders nest the AVCHD directory inside the PRIVATE directory. Following a standard agreed upon by many still camera manufacturers, solid state camcorders have a root level DCIM directory for still images. AVCHD is compatible with the Blu ray format as well as on its North American AG AC7 cousin. A successor model the AG AC8, is also capable of recording in AVCHD SD mode. Several models from JVC like the consumer camcorders GZ HM650, GZ HM670 and GZ HM690 as well as the professional camcorder JVC GY HM70 can record AVCHD SD video. AVCHD SD is not compatible with consumer DVD players, because it employs AVC video encoding instead of MPEG 2 Part 2. AVCHD SD can be played on a Blu ray Disc player without re encoding. Interlaced video had been originally designed for watching on a cathode ray tube television set. Material recorded for interlaced presentation may exhibit combing or ghosting when it is rescaled, filmed out or watched on a computer or another progressive scan device without proper deinterlacing. Some AVCHD 1080i camcorders can capture progressive video and record it within interlaced stream borrowing techniques from television industry. In particular, Progressive segmented frame (PsF) is utilized in some Panasonic (25p Digital Cinema), Canon (PF25, PF30) and Sony camcorders. The 2:3 pulldown technique is used in some 60 Hz versions of Canon (PF24) and Panasonic (24p Digital Cinema) camcorders for recording 24 frame/s progressive video. Most editing tools treat progressive video recorded within an interlaced stream as interlaced, though some editing systems and most standalone Blu ray Disc players are capable of recognizing the pulldown pattern to recover the original frames using the process known as inverse telecine.

Since the very beginning, the AVCHD specification had supported 720 line progressive recording mode at frame rates of 24 and 60 frames/s for 60 Hz models and 50 frames/s for 50 Hz models. Frame rates of 25 frames/s and 30 frames/s are not directly available in 720p mode, but can be simulated with frame repeating, when every frame is either repeated twice or a special flag in the video stream instructs a decoder to play every frame twice to adhere to output rate of 50 or 60 frames/s. Many of the digital compact cameras made by Panasonic, such as the DMC ZS3/DMC TZ7, DMC FT1, DMC FZ35/DMC FZ38, and DMC ZS 7/TZ 10 offer 720p video recording with effective frame rate of 25 or 30 frames/s in a format called AVCHD Lite (see below). Until the advent of AVCHD Progressive mode, native progressive scan video for 1080 line resolution had been available only in 24 frames/s variant. In 2010, Panasonic introduced a new lineup of consumer AVCHD camcorders with 1080 line 50p/60p progressive scan mode (frame rate depending on region). Panasonic advised that not all players that support AVCHD playback could play 1080 line 50p/60p video. In 2011, this mode was officially included into the AVCHD specification as part of 2.0 addendum, and has been called AVCHD Progressive. This mode uses the same AVCHD folder structure and container files for storing video, with the maximum bitrate of 28 Mbit/s. In 2011, Sony introduced consumer and professional AVCHD models capable of AVCHD Progressive recording. In 2012 JVC announced the GY HMQ10 model, which also can record AVCHD Progressive video.

Most AVCHD camcorders record audio using Dolby Digital (AC 3) compression scheme. Stereo and multichannel audio is supported. Audio data rate can range from 64 kbit/s to 640 kbit/s. In practice, data rates of 256 kbit/s and 384 kbit/s have been observed. Some professional models allow recording uncompressed linear PCM audio.

AVCHD specification allows using recordable DVDs, memory cards, non removable solid state memory and hard disk drives as recording media.

When the AVCHD standard was first announced, recordable DVD was the only recording medium. Rewritable DVDs cost more than write once discs. DVDs must be "finalized" to play back on set top players (though DVD RWs can be unfinalized again). Double layer recording is less robust than single layer recording. To use both sides of a double sided disc it must be flipped over, because camcorders have pickup from one side only. AVCHD DVDs can only be played back on DVD/Blu ray players specifically designed to do so. The AVCHD specification limits data rate for DVD based AVCHD camcorders to 18 Mbit/s, but no DVD based AVCHD camcorder manufactured to date is capable of recording at data rate higher than 12 Mbit/s (Canon, Sony) or 13 Mbit/s (Panasonic). A single sided single layer 8 cm DVD can fit only 15 minutes of video at 12 Mbit/s, 14 minutes at 13 Mbit/s. DVD pickup mechanism is very susceptible to vibration. 8 cm DVDs cannot be used in many slot loading drives and may even damage the drive. As the capacity of memory cards grew and their price dropped, DVDs use for recordable media declined. No DVD based AVCHD camcorders have been produced since 2008. While DVDs are no longer used for acquisition, they remain popular as distribution media. Many authoring programs offer "AVCHD" profile for recording high definition video on a DVD. Such AVCHD discs are incompatible with regular DVD Video players, but play in many Blu ray Disc players. A conventional single layer 12 cm DVD can store 35 minutes of video recorded at the maximum bitrate the AVCHD specification allows for DVD media—18 Mbit/s.

Panasonic and Sony developed several brand names for their professional as well as simplified versions of AVCHD.

AVCHD Lite is a subset of AVCHD format announced in January 2009, which is limited to 720p60, 720p50 and 720p24 and does not employ Multiview Video Coding. AVCHD Lite cameras duplicate each frame of 25fps/30fps video acquired by camera sensor, producing 720p50/720p60 bitstream compliant with AVCHD and Blu ray Disc specifications. As of 2013, AVCHD Lite seems to have been all but replaced with other formats. For example, the Panasonic DMC FZ 200 offers AVCHD Progressive recording mode (50fps/60fps acquisition and stream rate) as well as MP4 mode (25fps/30fps acquisition and stream rate).

Formerly known as "AVCHD with professional features," AVCCAM is the name of professional AVCHD camcorders from Panasonic's Broadcast division. Some of these professional features listed in early Panasonic advertising materials included 1/3 inch progressive 3CCD sensor, XLR microphone input, solid state media and capability of recording at the maximum AVCHD bitrate 24 Mbit/s. The aforementioned features are not exclusive to AVCCAM. Moreover, some of these features like CCD sensor technology have been dropped by Panasonic, while 24 Mbit/s recording rate is widely available from rival manufacturers even on consumer models.

Panasonic uses "AVCHD Pro" moniker to describe camcorders like the HDC MDH1, which combines consumer internal parts and controls with shoulder mount type body. Panasonic touts that the camcorder is "shaped for Pro Style shooting in Full HD" with shoulder mount type body being "preferred by professionals". NXCAM camcorders offer 1080i, 1080p and 720p recording modes. Unlike AVCCAM, not all NXCAM camcorders offer film like frame rates—24p, 25p, 30p—in 720p mode.

A DVD disc with AVCHD high definition video recorded on it is sometimes called an AVCHD disc. AVCHD discs cannot be played in a standard DVD player, but can be played in many Blu ray Disc players. Corel (formerly Ulead) DVD MovieFactory 7 can master AVCHD discs with menus. Various Sonic products can author AVCHD discs using HD/BD Plug in. Compressor 3.5 is capable of authoring AVCHD discs; subtitles are not supported. Nero Vision 9 can create an AVCHD disc with data rate up to 18 Mbit/s, or an AVCHD compliant folder for distribution on an HDD or a memory card with data rate up to 24 Mbit/s. Sony DVD Architect 5 can author AVCHD compliant discs with menus using AVC encoding as well as non standard discs using MPEG 2 encoding. In both cases data rate is limited to 18 Mbit/s. Panasonic HD Writer AE can author AVCHD content on DVDs, BD discs and on SD cards. MultiAVCHD can author AVCHD discs as well as Panasonic compliant AVCHD memory cards. Magix Movie Edit Pro 15 Plus with updates can author AVCHD content on DVDs, BD discs. Pinnacle Studio 11.1.2 and higher offers AVCHD disc output. Although AVCHD shares many format similarities with Blu ray Disc, it is not part of the Blu ray Disc specification. Consequently, AVCHD playback is not universally supported across Blu ray Disc players. Blu ray Disc players with "AVCHD" logo play AVCHD discs authored either on 8 cm or 12 cm DVDs. Players without such a logo are not guaranteed to play AVCHD discs. The 1080 line 50p/60p AVCHD Progressive recording mode employed in some camcorders, is not compliant with the current Blu ray Disc specification, though many current player models unofficially support it if they support AVCHD format.

Badaboom is a media converter that uses NVIDIA GPUs to accelerate conversion of AVCHD to mobile devices. HandBrake converts AVCHD Lite format to MP4 and MKV (tested on macOS; other versions available), AVI and OGM are supported in versions before 0.9.4. Roxio Toast 10 Titanium on macOS converts AVCHD to most formats. Total video converter is a converter for most video formats, including converting from AVCHD and burning AVCHD disc. iDealshare VideoGo can convert AVCHD to MP4, ProRes, MOV, AVI, WMV, FLV, DV, MKV, VOB etc.

VideoSinceAVCHD 1.0AVCHD 2.0Subtype High Definition (AVCHD HD) Standard Definition (AVCHD SD) AVCHD Progressive AVCHD 3D (stereoscopic)Frame size in pixels 1280x720 720x480 720x576 1920x1080 1440x1080 1280x1024 1920x1080 Frame rate30i, 25i, 24p60p, 50p, 24p30i25i60p, 50p24p, 25i, 30iFrame aspect ratio 16:9 4:3, 16:9 16:9 Video Compression MPEG 4 AVC/H.264; Main Profile (MP) and High Profile (HP), Level 4.1 (AVCHD 1.0) or 4.2 (AVCHD 2.0). Luminance sampling frequency 74.25 MHz 13.5 MHz 13.5 MHz 148.5 MHz 111.4 MHz 74.25 MHz Chroma sampling format 4:2:0 Quantization 8 bits (both luminance and chrominance) Audio (Dolby Digital) AC 3 Compression Dolby Digital (AC 3) AC 3 channel mode 1–5.1 channels AC 3 compressed bitstream rate 64 to 640 kbit/s Audio (PCM; NXCAM only) PCM type Linear PCM uncompressed audio PCM channel mode 1–7.1 channels PCM bitrate 1.5 Mbit/s (2 channels) System Stream type MPEG transport stream System data rate up to 28 Mbit/s File extension (generally) mts (on camcorder), m2ts (after import to computer) Media

For simplicity, the combination of frame rate and video format is denoted using the common simplified notation of NNx, where NN is the frame rate rounded to integer and x is the format ("i" for interlaced and "p" for pregressive). In this table, "60" actually runs at 59.94 frames/sec, "30" actually runs at 29.97 frames/sec, and "24" actually runs at 23.976 frames/sec, a relic of NTSC video.