Blu-ray Disc (BD)

               

   

Updated - September 24, 2008

 

Background:  DVD - The Digital Versatile Disc (also known as the Digital Video Disc) has now been widely available on a national basis throughout the US. for a decade and was the fastest growing consumer electronics product in history. Up until 2006 DVDs provided the highest quality of any widely available source of pre-recorded video.  However, the video quality of DVDs is clearly inferior to true high definition TV (HDTV).   Consumer electronics manufacturers and a few movie studios realized that once other sources of HDTV became available, a media was needed to bring pre-recorded HD movies to the consumer.  The first attempt to reach the marketplace was Digital VHS (D-VHS) tapes.  Both JVC and Mitsubishi manufactured D-VHS VCRs and a few studios released a modest number of movie titles in the D-VHS format.  D-VHS was from the beginning considered an interim format until a high definition optical disc was brought to the consumer marketplace.  D-VHS met only with very limited success and essentially died about a year before the introduction of HD optical discs.  

In the first half of this decade Sony and Toshiba, each joined by several other companies were developing high definition optical disc technologies that relied on the use of a blue laser to pack the needed additional data capacity onto an optical disc (as compared red lasers used for DVDs).  Ultimately Toshiba, and its partners that held several of the key patents for conventional DVDs, built their HD optical disc as an extension to the design of conventional DVDs.  This group won approval from the DVD patent licensing organization, the DVD Consortium - subsequently renamed the DVD Forum, for their alternative for a HD optical disc.  This format became known as HD-DVD.  

Sony, along with several partner companies, developed their own HD optical disc format that while their discs may appear similar to DVDs and HD-DVDs, they use a substantially different structure for storing the data within the disc.  This format is much less tied to the DVD technology, and less encumbered by the existing DVD related patents, than is the HD-DVD format.  Sony and their partners named their HD optical disc format Blu-ray Disc (BD) and created a new standards and licensing organization called the Blu-ray Disc Association.

Both HD-DVD and BD do share some things in common in addition to similar size disc.  Both HD-DVD and  BD support discs with multiple layers but both formats are currently limited to two layers for production discs.  Both formats use a blue laser whose shorter wavelength (as compared to the red laser used for DVDs) allows for more data storage on each layer of the disc.  However, the BD format allows for higher data density per layer (approx. 25 GB per layer for BD as compared to 15 GB per layer for HD-DVD).  Both formats have adopted the same three video encoding techniques (i.e. video codecs).  Each of these 3 video codecs is capable of producing excellent results as long as the video is encoded at high enough data rate.  However, the most efficient codec can produce equivalent results to the least efficient at less that one half of the data rate.  The 3 video codecs supported by both BD and HD-DVD are:

Video Codec	Comments
MPEG-2	HD version of the codec used for DVDs.  MPEG-2 is standardized by the Motion Picture Experts Group (MPEG) of the International Standards Organization (ISO).  MPEG-2 is the oldest and least efficient of the 3 available HD video codecs, but requires the least processing power to both encode and to decode.
AVC	Based on the International Telecommunications Union (ITU) standard H.264 approved by the official MPEG group of the ITU (and jointly with the International Standards Organization - ISO).  AVC is the HD version of MPEG-4 and while substantially more efficient than MPEG-2 for encoding HD (i.e., requires lower data rate for the same image quality), it requires the most processing power of the 3 available HD video codecs for encoding and decoding.
VC-1	VC-1 is based on the codec first developed by Microsoft for Windows Media Player version 9. VC-1 has been standardized by the Society of Motion Picture and Television Engineers (SMPTE) where is bears the official name 421M video codec.  VC-1 is slightly more efficient than AVC (i.e., capable to producing the equivalent image quality at a somewhat lower data rate) and also requires somewhat less processing resources for the encoding and decoding as compared to AVC, but still substantially more processing resources as compared to MPEG-2)

 

In addition to supporting the same set of HD video coding formats, BD and HD-DVD standards include the same set of required and optional audio formats, including new Dolby Digital and DTS advanced audio formats.  However, none of the current generation of BD or HD-DVD players can fully support all of the new (optional) formats allowed by the respective BD and HD-DVD standards (e.g., no player currently supports DTS-HD MA, see below).  All of the players support the same baseline Dolby Digital and DTS surround sound formats, as used on DVDs, and all software is encoded with these baseline (i.e., default) formats.  Therefore, as a minimum the HD disc player will be able to output standard Dolby Digital or DTS digital audio.  The new, higher fidelity, Dolby surround formats are Dolby Digital Plus and Dolby Digital TrueHD, with TrueHD being the highest fidelity Dolby format as it provides lossless compression (i.e, decoded output is bit-for-bit identical to the original master recording).  DTS has also developed two new formats under the overall name DTS-HD.  These are "DTS-HD High Resolution Audio" and "DTS-HD Master Audio" (with DTS-HD MA being the highest fidelity DTS format as it provides lossless compression).  The highest fidelity advanced formats require data rates too high to be passed over conventional digital optical connections to an external Audio/Video Receiver (AVR) or processor.  As a result, the various disc player manufacturers have taken alternative approaches to getting this improved audio out of their disc players.  One alternative is to output the digital audio data stream via the HDMI interface (along with the Video data) and the advanced audio is only enabled when connected to a new generation of AVR that includes HDMI inputs as well as decoding for the advance audio format.  A second alternative is to provide, within the disc player, the decoding of the advanced audio format and to then encode the audio as linear Pulse Code Modulation (PCM) and output then the PCM audio via the HDMI, along with the digital video.  Many recent vintage AVRs that have HDMI inputs can accept PCM audio and the AVR in this case does not require any capability for decoding the new advanced audio formats.  A third alternative is to have the disc player decode the advanced audio format and also perform the digital to analog conversion and provide discrete analog outputs for each of the channels (either 5.1 or 7.1 channels). 

The End of HD-DVD - On Feb. 19th  Toshiba Corp. President Atsutoshi Nishida said in announcing that his company would halt the manufacture of HD-DVD players that he wanted to avoid confusion among consumers.  Since Toshiba was the primary developer of the HD-DVD technology and currently the only manufacturer of dedicated HD-DVD players (both LG and Samsung manufacturer dual format players and some others buy relabeled players from Toshiba) this will effectively mark the end of the HD format war between the competing formats (i.e., HD-DVD and Blu-ray Disc).  Universal also announced on Feb. 19th. that they will now focus on releasing movies on Blu-ray Disc.  Announcements of support for the Blu-ray Disc format followed a few weeks later from Paramount and Dreamworks, the only other major studios that had been releasing HD content exclusively on HD-DVD.   The actions effective ended the format war between Blu-ray Disc and HD-DVD with Blu-ray Disc as the victor.

For more technical details on the BD and HD-DVD disc formats and technology check these links for:  Blu-ray Disc and for HD-DVD.

 

BD Comes to Market

Toshiba brought their first HD-DVD player to market later than planned in April 2006 and Samsung followed a few months later (June 2006) with the first BD player.  Both formats had their share of problems with first generation hardware and software at the beginning.  The BD camp had somewhat more problems than HD-DVD in the first several months after the initial BD introduction.  A number of manufacturers had planned to introduce their initial BD players in the May/June 2006 time frame.  However, only Samsung actually had a player in production by that time (in June 2006, one month later than they has previously announced).  Also the only manufacturer of the pre-recorded discs (i.e., movies) at the BD introduction was Sony and for the first several months they were only able to manufacturer single layer discs authored using MPEG-2 encoding.  This combination of the lowest capacity disc (i.e., single layer) format and the least efficient encoding technique (i.e, MPEG-2) resulted in discs with generally inferior quality, as compared to the initial HD-DVD releases or later BD releases. In some cases the initial Sony manufactured discs also had relatively low quality transfers from the original film which further contributed to poor video quality on certain of the initial BD releases.  However, by the end of 2006 BD manufacturers had overcome most of the startup problems.  The BD camp saw other manufactures (Panasonic, Pioneer, Sony) introduced their first generation of players in late 2006 and the production of 2-layer BD discs began was well as the use of the more advanced video codecs (e.g, AC-1).  Sony also introduced in November 2006 the Playstation 3 that supports playback of BD software.  Also Samsung issued a firmware update to their first generation BD player in Oct. 2006 that corrected their player's biggest technical issue and this brought its level of performance in line with their competitors 1st generation BD players. While the quality of film transfers still varies by title, there has been a general improvement, especially as compared to some of the earliest BD releases.  

All BD players can provide high definition video output in the 720p, 1080i  and 1080p HD formats.    Most movies are recorded on BDs in a 1080p format at 24 frames per second (referred to as 1080p/24) to match the 24 frame per second rate of motion picture film.  The 1st generation Samsung player (as well as the 1st generation Panasonic BD player) used an internal chip set that only decoded to 1080i format.  Therefore, these manufacturers included an additional signal processing chip in their BD players to perform de-interlacing back to 1080p/60 format for output from the player via the HDMI interface.  Thus, the recorded 1080p/24 information was converted to 1080i/60 then converted again to 1080p/60.  The 1st generation Pioneer and Sony BD players introduced at the end of 2006 employed a chip set that could directly output 1080p/60, thus eliminating the additional conversions associated with interlacing and de-interlacing.  Virtually all of the current generation of BD players (2008) can directly decode and output video in 1080p/24 format.

 

BD Players (2008)   

For BD players there are more choices of brand names.  All of the BD players offer 1080p/60 output and also support a native 1080p/24 output for use with those HDTV displays that can currently accept this video format.  The currently available (Sept. 2008) and announced soon-to-be-released  models of  BD players (for the U.S. market) are:

Manufacturer	Model	BD Profile	Supported Advanced Audio Formats (note 2)
Denon	DVD-2500BT	1.1	ALL (bitstream)
Denon	DVD-3800BD	1.1	ALL (bitstream, internal decoding w/LPCM & 7.1 analog outputs)
Insignia (sold only at Best Buy - made by Funai)	NS-BRDVD	1.1	All (bitstream)
Magnavox (made by Funai)	NB500MG9	1.1	All (bitstream)
Panasonic	DMP-BD30 (discontinued)	1.1	ALL (bitstream)
Panasonic	DMP-BD35	2.0	ALL (bitstream)
Panasonic	DMP-BD50 (discontinued)	2.0	ALL (bitstream, internal decoding LPCM and 5.1 Analog outputs)
Panasonic	DMP-BD55	2.0	ALL (bitstream, internal decoding LPCM and 7.1 Analog outputs)
Philips	BD-P1000 (discontinued)	1.0	None
Philips	BDP7200	1.1	ALL (via bitstream, internal decoding for standard Dolby Digital and DTS formats with LPCM & 5.1 analog outputs)
Pioneer	BDP-95HD	1.0	ALL (bitstream)
Pioneer	BDP-51FD	1.1	ALL (bitstream, internal decoding LPCM and 7.1 channel analog outputs)
Pioneer	BDP-05FD	1.1	ALL (bitstream and internal decoding with LPCM and 7.1 channel analog outputs)
Samsung	BD-P1400 (discontinued)	1.0	ALL (bitstream)
Samsung	BD-P1500	1.1	ALL (bitstream)
Samsung	BD-P2550	1.1	ALL (via bitstream and all but DTS-HD internally decoded and output via LPCM over HDMI and also via 7.1 channel analog)
Sharp	BD-HP20U (discontinued)	1.0	Only Dolby TrueHD (internal decoding with LPCM output)
Sharp	BD-HP50U	1.1	ALL (bitstream, internal decoding with LPCM & 5.1 analog output)
Sony	BDP-S300 (discontinued)	1.0	None
Sony	BDP-S350	1.1 (2.0 with subsequent firmware update)	ALL (bitstream)
Sony	BDP-S500 (discontinued)	1.0	Only Dolby TrueHD (bitstream)
Sony	BDP-S550	2.0	ALL (bitstream, internal decoding w/LPCM output)
Sony	BDP-S2000ES	1.0	Only Dolby TrueHD (bitstream)
Sony	Playstation 3	2.0	ALL (internal decoding and LPCM output)
Sylvania (made by Funai)	NB500SL9	1.1	All (bitstream)

Notes:  

1. Information on future models is preliminary and subject to change.

2. Advanced Audio refers to support for the Dolby Digital TrueHD and/or DTS HD-Master Audio (DTS HD-MA).  ALL in the table means that the player supports both Dolby TrueHD and DTS HD-MA.  Some players may include internal decoding for the advanced audio formats while other players may simply provide a bitstream output via the HDMI, in which case a separate AV Receiver or Processor would be required in order to decode the advanced audio data. All discs and players support the core Dolby Digital and DTS surround audio and those formats are available in any case, even if the advanced audio formats are not supported.  Also all players that support any of the advanced audio formats also support output of uncompressed linear PCM audio (as found on some Blu-ray Disc movie titles). 

 

BD Profiles

All BD players introduced in 2008 support at least the new BD Profile 1.1 (called "Bonus View") requirements.  Such profile 1.1 players must implement additional features, beyond the previous Profile 1.0 players, including support for "picture in a picture" (PIP), support for secondary audio decoding and include as a minimum 256 MB of 'persistent' memory.  These new features were mandated by the Blu-ray Disc Association through an updated "BD profile" (i.e., essentially an updated specification of the minimum required functions for BD players).  All new BD players receiving approval from the Blu-ray Disc Association after October 2007 were required to support this updated BD Profile version 1.1.  The first movie BD release that will be supporting the new features enabled by Profile 1.1 (e.g., PIP) was release on January 1, 2008.  The optional BD Profile 2.0 (also called "BD-Live") requires players include a high speed internet connection (ethernet and/or wireless) and additional memory for supporting web-enabled features to be included on some BD disc titles.  A firmware update for the Playstation 3 in late 2007 that updated it to support the requirements of Profile 1.1 and Sony subsequently upgraded the Playstation 3 to Blu-ray Disc Profile 2.0 making it the first available player to support the internet enabled features included with Profile 2.0.  Subsequently several new standalone players have been introduced that support BD Profile 2.0 (see table above of BD players).  Some recent BD movie releases include web enabled features when played on a Profile 2.0 player.  These BD profiles are backward compatible in that older profile 1.0 players will continue to play the basic movie, just not offer the additional features associated with the later BD profiles.  

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