VCD
PLAYER CIRCUIT DIAGRAM
Vcd
player Is generally a very useful device which is used to play vcd or cd
Its
full form Is video compact disk
1. Things which are used
in vcd player are
a.pictures
b.
any audio songs im mp3,wav,aac
Video CDs comply with the CD-i Bridge format, and are authored using tracks in CD-ROM XA mode. The first track of a VCD is in CD-ROM XA Mode 2 Form
1, and stores metadata and menu information inside an ISO 9660 filesystem. This track
may also contain other non-essential files, and is shown by operating systems
when loading the disc. This track can be absent from a VCD, which would still
work but would not allow it to be properly displayed in computers.[3]
The rest of the tracks are usually in CD-ROM XA Mode 2 Form 2
and contain video and audio multiplexed in an MPEG program stream (MPEG-PS) container, but CD
audiotracks are also
allowed.[3] Using Mode 2 Form 2 allows roughly 800 megabytes of VCD
data to be stored on one 80 minute CD (versus 700 megabytes when using CD-ROM
Mode 1). This is achieved by sacrificing the error correction redundancy
present in Mode 1. It was considered that small errors in the video and audio
stream pass largely unnoticed. This, combined with the net bitrate of VCD video
and audio, means that almost exactly 80 minutes of VCD content can be stored on
an 80-minute CD, 74 minutes of VCD content on a 74-minute CD, and so on. This
was done in part to ensure compatibility with existing CD drive technology,
specifically the earliest "1x" speed CD drives.
Video
Video specifications
·
Resolution:
·
Framerate:
Although many DVD video players support playback of VCDs, VCD
video is only compatible with the DVD-Video standard if encoded at 29.97 frames per second or 25
frames per second.
The 352x240 and 352x288 (or SIF) resolutions were chosen because it is half
the horizontal and vertical resolution of NTSC video, and half the horizontal
resolution of PAL (the vertical resolution of PAL already being half of the 576
active lines). This is approximately half the resolution of an analog VHS tape
which is ~330 horizontal and 480 vertical (NTSC) or 330x576 (PAL).
Audio
Audio specifications
As with most CD-based formats, VCD audio is incompatible with
the DVD-Video standard due to a difference in sampling
frequency; DVDs require 48 kHz, whereas VCDs use 44.1 kHz.
Advantages of
compression
By compressing both the video and audio streams, a VCD is able
to hold 74 minutes of picture and sound information, nearly the same duration
as a standard 74 minute audio CD. The MPEG-1 compression used records mostly
the differences between successive video frames, rather than write out each frame
individually. Similarly, the audio frequency range is limited to those sounds
most clearly heard by the human ear.
Other features
PlayBack Control (PBC) added in VCD 2.0
requires a special 'Return' button
The VCD standard also features the option of DVD-quality still
images/slide shows with audio, at resolutions of 704x480 (NTSC) or 704x576
(PAL/SECAM). Version 2.0 also adds the playback control (PBC), featuring a
simple menu like DVD-Video.
Internal Control
An example of the software control chart (taken from Flower
And Snake disc 1 of 3) including menu commands found in the
configuration volume as "CDI_VCD.CFG"
CONTROLS=ALL
CURCOL=YELLOW
PSDCURCOL=RED
PSDCURSHAPE=ARROW
INITLANG=DAT
SUBTTYPE=OVERLAYED
SUBTTCOL=EBEBEB
SUBSTCOL=101010
SUBTBCOL=0
SUBTACOL=999999
CENTRTRACK=2
AUTOPLAY=AUTO_ON
DUALCHAN=DUAL_ON
TIMECODE_X=64
TIMECODE_Y=100
LOTID_X=64
LOTID_Y=64
ALBUM=STANDARD
Similar formats
CD-i Digital Video
Shortly before the advent of White Book VCD, Philips started
releasing movies in the Green Book CD-i format, calling
the subformat CD-i Digital Video (CD-i DV). While these used a similar format
(MPEG-1), due to minor differences between the standards these discs are not
compatible with VCD players. Philips' CD-i players with the Full Motion Video
MPEG-1 decoder cartridge would play both formats. Only a few CD-i DV titles
were released before the company switched to the current VCD format for
publishing movies.
XVCD
XVCD (eXtended Video CD) is the name generally given to any
format that stores MPEG-1 video on a compact disc in CD-ROM XA Mode 2 Form 2,
but does not strictly follow the VCD standard in terms of the encoding of the
video or audio.
A normal VCD is encoded to MPEG-1 at a constant bit rate (CBR),
so all scenes are required to use exactly the same data rate, regardless of
complexity. However, video on an XVCD is typically encoded at a variable bit
rate (VBR), so complex scenes can use a much higher data rate for a short time,
while simpler scenes will use lower data rates. Some XVCDs use lower bitrates
in order to fit longer videos onto the disc, while others use higher bitrates
to improve quality. MPEG-2 may be used instead of MPEG-1.
To further reduce the data rate without significantly reducing
quality, the size of the GOP can be increased, a different MPEG-1 quantization matrix can be used, the maximum data rate can be exceeded, and
the bit rate of the MP2 audio can be reduced (or even the use of MP3 audio
instead of MP2 audio). These changes can be advantageous for those who want to
either maximize video quality, or use fewer discs.
KVCD
KVCD (K Video Compression Dynamics) is an XVCD variant that
requires the use of a proprietary quantization matrix, available for non-commercial use. KVCD is
notable because the specification recommends a non-standard resolution of
528x480 or 528x576. KVCDs encoded at this resolution are only playable by
computers with CD-ROM drives, and a small number of DVD players.[5]
DVCD
DVCD or Double VCD is a method to accommodate longer videos on
a CD. A non-standard CD is overburned to
include up to 100 minutes of video. However, some CD-ROM drives and players
have problems reading these CDs, mostly because the groove spacing is outside
specifications and the player's laser servo is unable to track it.
DVI
DVI (Digital
Video Interactive) is a compression
technique that stored 72 minutes of video on a CD-ROM. In 1998, Intel acquired the
technology from RCA's Sarnoff Research Labs. DVI never caught on.[6]
SVCD
Super Video CD is a format intended to be the successor
of VCD, offering better quality of image and sound.
Video CDs were unable to gain acceptance as a mainstream format
in North America, chiefly because the established VHS format was less
expensive, offered comparable video quality, and could be recorded over.[7] The advent of recordable CDs, inexpensive recorders, and compatible DVD players spurred VCD
acceptance in the US in the late 1990s and early 2000s.[8] However, DVD burners and DVD-Video recorders were available
by that time, and equipment and media costs for making DVD-Video fell rapidly.
DVD-Video, with its longer run time and much higher quality, quickly
overshadowed VCD in areas that could afford it. In addition many early DVD
players could not read recordable (CD-R) media,[9] and this limited the compatibility of home-made VCDs.
Almost every modern stand-alone DVD-Video player can play VCDs burned on
recordable media.[citation needed]
In Asia
As of 2014, VCDs and
DVDs are the norm for home media in the Philippines. Blu-ray discs are also
available but are only displayed at small separate shelves at the counter.
The VCD format was very popular throughout Asia[10] (except Japan and South Korea) in the late 1990s through
the 2000s, with 8 million VCD players sold in China in 1997 alone,[11] and more than half of all Chinese households owning at
least one VCD player by 2005.[12] However, popularity has declined over the years, as the
number of Hong Kong factories that produced VCDs dropped
from 98 in 1999 to 26 in 2012.[13]
This popularity is, in part, because most households did not
already own VHS players when VCDs were introduced, the low price of the
players, their tolerance of high humidity (a notable problem for VCRs), easy
storage and maintenance, and the lower-cost media.[8] Western sources have cited unauthorized content as a
principal incentive for VCD player ownership.[14][15][16]
VCDs are often produced and sold in Asian countries and regions,
such as Mainland China, Taiwan, Hong Kong, Singapore, Malaysia, Thailand, Burma, Indonesia, Philippines, Vietnam, India, Pakistan and Bangladesh. In many Asian countries, major Hollywood studios (and Asian
home video distributors) have licensed companies to officially produce and
distribute the VCDs, such as MCA
Home Video in Pakistan, Intercontinental Video Ltd. of Hong Kong, Sunny Video in
Malaysia, Vision in Indonesia, CVD International and Pacific Marketing and
Entertainment Group in Thailand, Excel Home Video in India, Berjaya-HVN and
InnoForm Media in both Malaysia and Singapore, Scorpio East Entertainment in
Singapore, as well as VIVA Video, Magnavision Home Video, and C-Interactive
Digital Entertainment in the Philippines. Legal Video CDs can often be found in
established video stores and major book outlets in most Asian countries. They
are typically packaged in jewel cases like commercial CDs, though
higher-profile films may be released in keep cases. The consumer should always check for the VCD or DVD logo so as
to avoid purchasing the wrong format.
In Asia, the use of VCDs as carriers for karaoke music is very common. One channel would feature a mono
track with music and singing, another channel a pure instrumental version for
karaoke singing. Prior to this, karaoke music was carried on laserdiscs.
Worldwide trends
VCD's growth has slowed in areas that can afford DVD-Video, which offers most of the same advantages, as well as better
picture quality[17] (higher resolution with fewer digital compression
artifacts) due to its larger storage capacity. However, VCD has simultaneously
seen significant new growth in emerging economies like India, Indonesia, South America and Africa as a low-cost alternative to DVD. As of 2004, the
worldwide popularity of VCD was increasing.[18][19]
Compared with VHS
Overall picture quality is intended to be comparable to VHS video.[20] Poorly compressed VCD video can sometimes be of lower quality than VHS
video, for example exhibiting VCD block artifacts[21] (rather than the analog noise seen in VHS sources), but
does not deteriorate further with each use. Producing video CDs involves
stripping out high- and low-frequency sounds from the video, resulting in lower
audio quality than VHS.[21] While both formats need fast-forwarding to find certain
scenes, rewinding to the beginning upon reaching the end is not required in
VCD. The resolution is just half below that of common VHS resolution.
Video CDs do not come with closed caption (on-screen text to aid viewers with
hearing problems). When watching a film that exceeds 74 minutes, which is the
maximum video capacity of one disc, a viewer has to change the disc upon
reaching halfway (unless the discs are played on a VCD changer that can hold
multiple discs and play them automatically in succession), whereas a single VHS
can hold 3½ hours of continuous video (as of 2014, 10 hour VHS tapes are
available).
Compared with DVD
Films released on VCD can come as many as 3
discs, depending on the length of the film. Cases of VCDs are shaped like those
of audio CDs. DVD and Blu-ray cases, however, favor height over width.
When playing a DVD, the viewer is brought to a main menu which
gives them options (watch the feature film, view "deleted scenes",
play some special applications, etc.). VCDs are usually straightforward,
playing them often goes directly to the video with extras (mostly trailers and
commercials) taking place before or after it, like on a VHS cassette.
Subtitles are found on many Asian VCDs but cannot be removed,
unlike DVDs. The subtitles are embedded on the video during the encoding
process ("hardsubbed"). It's not uncommon to find a VCD with
subtitles for two languages.
Though the VCD technology can support it, most films carried on
VCDs do not contain chapters, requiring the viewer to fast-forward to resume
the program after playback has been stopped. This is mostly because VCD
technology is able to start playback at a chapter point but there is nothing to
signal the player that the chapter has changed during a program. This can be
confusing for the user as the player will indicate that it is still playing
chapter 1 when it has played through to chapter 2 or later. Pressing the Next
button would cause playback from the beginning of chapter 2. However, preview
material is sometimes stored in a separate chapter, followed by a single
chapter for the film.
VCDs are often bilingual. Because they feature stereo audio,
disc players have an option to play only the left or right audio channel. For
example, ERA of Hong Kong's release of the animated film The Iron Giant features English on the left audio
channel and Cantonese on the right; more commonly Hong Kong VCDs will feature
Mandarin on one channel and Cantonese on the other. This is similar to
selecting a language track on a DVD, except it's limited to 2 languages, due to
there being only two audio channels (left and right). The audio track
effectively becomes monaural.
VCD's most noticeable disadvantage compared to DVD is image
quality, due both to the more aggressive compression necessary to fit video
into such a small capacity as well as the compression method used.
Additionally, VCDs are available only in stereo, while DVDs are capable of six
channels of discrete surround sound. The audio compression of VCDs also suffers
from not being able to pull off the Haas effect for matrixed surround sound.
Hardware and software support
Early devices supporting Video CD playback include the Philips CD-i systems and the Amiga CD-32 (albeit via an optional decoder card).[7]
Video CDs are not popular in the US, Canada and Europe, so its
support is limited among mainstream software. Windows Media Player prior to version 9 and QuickTime Player do not support playing VCD directly,
though they can play the .DAT files (stored under \MPEGAV for video and audio
data) reliably,[22][23] and plugins were available. Windows Vista added native support of VCD along with
DVD-Video and can launch the preferred application upon insertion. The disc
format is also supported using Windows Media Player Classic variations and VLC Media Player both support VCDs natively.
Direct access playback support is available within Windows XP MCE, Windows Vista and newer (including Windows 10), classic Mac OS, BSD, macOS,
and Linux among others, either directly or with updates and
compatible software.
Disc playback is also available both natively and as an option
on some CD- and DVD-based video game consoles, including PC-FX, Sega Saturn (pictured), Sega Dreamcast, and Sony PlayStation (only on the SCPH-5903 model).
Most DVD players are compatible with VCDs, and
VCD-only players are available throughout Asia, and online through many shopping
sites. Older Blu-ray and HD-DVD players also retained
support, as do CBHD players as well. However, most current Blu-ray players and
the Sony PlayStation 3/4 cannot play VCDs; this is because while they have
backwards playback compatibility with the DVD standard, these player can not
read VCD data because the player software does not have support for MPEG-1
video and audio.
