Hdmi Block Diagram; Typical Video Frame - Philips 42PF9731D Service Manual

EN 158 9. BJ2.4U/BJ2.5U LA
HDMI Source
Video
Transmitter
Audio
Figure 9-10 HDMI block diagram
Audio, video, and auxiliary data is transmitted across the three
TMDS data channels. The video pixel clock is transmitted on
the TMDS clock channel and is used by the receiver as a
frequency reference for data recovery on the three TMDS data
channels.
Video data is carried as a series of 24-bit pixels on the three
TMDS data channels. TMDS encoding, converts the 8 bits per
channel into the 10 bit DC-balanced transition minimized
sequence, which is then transmitted serially across the pair at
a rate of 10 bits per pixel clock period.
Video pixel rates can range from 25 MHz to 165 MHz. Video
formats with rates below 25 MHz (e.g. 13.5 MHz for 480i/
NTSC) can be transmitted using a pixel-repetition scheme. The
video pixels can be encoded in either RGB, YC
YC C 4:2:2 formats. In all three cases, up to 24 bits per pixel
B R
can be transferred.
In order to transmit audio and auxiliary data across the TMDS
channels, HDMI uses a packet structure. In order to attain the
higher reliability required of audio and control data, this data is
protected with a BCH error correction code and is encoded
using a special error reduction coding to produce the 10-bit
word that is transmitted.
Basic audio functionality consists of a single IEC 60958 audio
stream at sample rates of 32 kHz, 44.1 kHz, or 48 kHz. This can
accommodate any normal stereo stream. Optionally, HDMI can
carry a single such stream at sample rates up to 192 kHz or
from two to four such streams (3 to 8 audio channels) at sample
rates up to 96 kHz. HDMI can also carry IEC 61937
compressed (e.g. surround-sound) stream at sample rates up
to 192 kHz.
The DDC is used by the source to read the sink's Enhanced
Extended Display Identification Data (E-EDID) in order to
discover the sink's configuration and/or capabilities.
HDMI is backward compatible with DVI (1.0). Compared with
DVI, HDMI offers extra:
• YUV 4:4:4 (3 x 8-bit) or 4:2:2 (up to 2 x 12-bit), where DVI
offers only RGB 4:4:4 (3 x 8 bit).
• Digital audio in CD quality (16-bit, 32/44.1/48 kHz), higher
quality available (8 channels, 192 kHz).
• Remote control via CEC bus (Consumer Electronics
Control): allows user to control all HDMI devices with the
TV's remote control and menus.
• Smaller connector (SCART successor).
• Less cables: e.g. from 10 audio/9 video cables to 3 HDMI
cables.
Implementation
The IC used is the TDA9975 (triple 10-bit video converter
interface), item 7B11 on the SSB.
• Power supply: 3V3 and 1V8.
• Inputs:
Circuit Descriptions, Abbreviation List, and IC Data Sheets
HDMI Sink
Video
TMDS Channel 0
TMDS Channel 1
TMDS Channel 2
Receiver
Audio
TMDS Clock Channel
EDID
ROM
Display Data Channel (DDC)
E_13950_062.eps
C 4:4:4, or
B R
– HDMI connectors (Video, Audio, HDCP, Control).
– Analogue (YPbPr, RGB, and H/V).
• Control signals:
2
– I C coming from TDA9975 (MM-BUS1).
– 13.5 MHz clock for analog format detection.
– JTAG.
• Output to PNX2015: Video (DV4 and DV5):
– YUV 4:2:2 20 bit (10 bit Y, 10 bit UV multiplexed) +
clock + sync.
– ITU-656 (compressed DVD video) encoded in data
stream.
• Output to VIPER:
– Audio: S/PDIF.
– Interrupt signal.
120304
Data Content
HSYNC
Control
Period
V
S
Y
N
C
Data
Island
Period
Figure 9-11 Typical video frame
A typical video frame is built up with the following info blocks:
• Control Period.
– Transmission of the pre-amble.
– Character synchronization.
• Data Island Period.
– Audio and auxiliary information are carried in packets
within a Data Island.
– HSYNC, VSYNC are also carried during Data Island
Period.
– Packet Types:
–
–
–
• Video Data Period.
– Carries the pixels of an active video line.
– TMDS encoding.
Data Islands: Audio Formats
• All current CE audio formats can be transmitted.
• Supports compressed formats like:
– Dolby Digital.
– Dolby Digital EX (THX-EX).
– DTS.
– Etc.
• Supports uncompressed formats ("discrete" PCM audio):
– Up to 8 channels, up to 192 kHz, up to 24 bits.
• CD-quality audio is always available, so the user will
always hear sound.
– 2 channel, 16 bit at 32 kHz (STB), 44.1kHz (CD), or 48
kHz (DVD)
Data Islands: InfoFrames (EIA/CEA-861B)
• Auxiliary Video Information (AVI):
– Specifies active aspect ratio, colorimetric info, pixel
encoding, etc.
• Audio InfoFrame:
– Describes audio stream, speaker/channel allocation,
etc.
• Source Product Info:
Active Video
Audio Sample.
Audio Clock Recovery.
InfoFrame: Aux. Video IF, Audio IF, MPEG IF,
vendor-defined IF.
Video
Data
Period
F_15400_011.eps
210405