Compression - LG BH100 Training Manual

OVERVIEW
Because consumer electronics devices are using increasingly complex digital signal processing to
enhance the clarity and detail of the content, synchronization of video and audio in user devices
has become a greater challenge and could potentially require complex end-user adjustments. HDMI
1.3 incorporates an automatic video/audio synching capability that allows devices to perform this
synchronization automatically with total accuracy.
HDMI REVISIONS
The HDMI interface was originally released in late 2002. Revision 1.1 was released in 2004 and
added support for DVD-Audio, as well as other aspects. Revision 1.2 was released in 2005 and most
notably added support for 8ch audio. An update to version 1.2 was added in late 2005, to revision
1.2a, with improvements to CEC. The current revision, 1.3, was released in June of 2006 with
increased bandwidth and support for lossless audio formats of Dolby TrueHD and DTS-HD Master
Audio. The goal of HDMI is to stay "ahead of current technologies", and revision 1.3 is a perfect
example. The abilities of 1.3 reach far beyond currently available technologies. All version of HDMI
interface are compatible with other revisions. If devices with different versions of HDMI are
connected, the older revision is fully supported.

COMPRESSION

The Moving Picture Experts Group (MPEG) is the working group of ISO/IEC in charge of the development
of standards for coded representation of digital audio and video. Established in 1988, the group has
produced MPEG-1, the standard on which such products as Video CD and MP3 are based, MPEG-2, the
standard on which such products as Digital Television set top boxes and DVD are based, and MPEG-4,
the standard for multimedia for the fixed and mobile web. (MPEG-3 is the designation for a group of
audio and video coding standards designed to handle HDTV signals in the range of 20 to 40 Mbps. In
the midst of development, it was determined that similar results were possible with slight modifications
to MPEG-2. Therefore, MPEG-3 was discontinued and never implemented. MPEG-3 should not be
confused with MPEG-1 Part 3 Layer 3, commonly known as MP3.)
As mentioned above, MPEG-1 is the compression format for Video CD and MP3. MPEG-2 is the
compression format used by both DVD and HDTV (ATSC broadcast). While MPEG-2 has six possible
profiles @ four possible levels, it is most often seen in one of three variants; MP@ML (Main Profile@Main
Level) for DVD, and two variants of MP@HL (Main Profile@High Level) for HDTV. DVD allows for
resolutions of 720x480, 704x480, 352x480, or 352x240. The HDTV variants allow for 1920x1080 and
1280x720 resolutions. On the audio side, MPEG-2 expands on MPEG-1's audio compression by allowing
for multi-channel audio.
The fundamental complexities of the MPEG-2 compression format have required that decoders evolve
into basic computers. This over-simplified analogy leads to part of the understanding of the development
of MPEG-4. Since the decoding devices are essentially computers, there is an increased processing
ability; therefore MPEG-4 was developed as a more robust compression format. MPEG-4 improves
upon some of the limitation of MPEG-2, such ad compression artifacts and macro-blocking. The
aspect of MPEG-4 discussed in this manual is MPEG-4 Part 10. This part/version is often referred to as
MPEG-4 AVC (Advanced Video Coding) or as H.264. The main purpose of using MPEG-4 over MPEG-2 is
that MPEG-4 uses much lower bitrates than MPEG-2. MPEG-4 will typically be found in BD and HD
DVD movies and some limited use by DirecTV.
Another compression format to mention is VC-1. VC-1 is the informal name of the SMPTE 421M video
codec. VC-1 uses similar bitrates and resolutions as MPEG-4 and is primarily used by Microsoft's
BH100 Blu-ray Player
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Overview