Audio/video synchronization issues arise because video processing is more intensive than audio processing. As a result, audio is ready for playback before the video. Without synchronization, what viewers hear will not match what they see on the screen. Also known as "lip sync," A/V synchronization is maintained by delaying playback of the audio stream, until the video stream has finished processing. The actual delay required for synchronization depends upon the type of A/V
signals and the current video mode.
Synchronization also plays a role in wireless multi-channel speaker applications. Given the inherent processing delays of wireless transmission, it takes more time for transmitted channels than
non-transmitted channels to output audio. The non-transmitted channels, therefore, must have additional delay to synchronize them with the transmitted channels.
With the introduction of the TPA5050 digital audio delay, TI offers
developers a cost-effective way to implement lip sync delay in a single
chip that is easily configured and reduces system complexity, which will
ultimately provide consumers an even better end product when purchasing
newer TV technologies, including DLP® HDTVs. Additionally, given the
tight physical constraints of A/V applications such as LCD TVs,
minimizing the size of components on the printed circuit board (PCB) is
an important design consideration.
Because the new chip can provide up to 170 milliseconds (ms) of delay
per channel--and with resolution down to a single sample--the TPA5050
digital audio delay can make the audio and video delay imperceptible.
With 170 ms of delay per channel, the TPA5050 digital audio delay can
synchronize the most demanding TV applications. Its integrated
architecture and 4mm x 4mm QFN package minimizes board footprint.
In addition to minimizing cost, board space and configuration
complexity, the TPA5050 digital audio delay will automatically clear the
delay memory during a delay time change, eliminating undesirable pops
and clicks. The TPA5050 digital audio delay supports 16 to 24 bit data,
sample rates from 32 to 192 kHz, and all standard audio configuration
interfaces, including I2S, Left- and Right-Justified. All internal
clocking on the TPA5050 digital audio delay is generated from the bit
clock so no crystal or oscillator is needed. The inputs are 5 Volts
tolerant so interfacing with a host of microcontrollers and audio
processors is not an issue. Developers requiring longer delays for
professional or specialized applications can cascade multiple TPA5050
The TPA5050 complements other TI digital and analog products that
support audio applications, such as Class D amplifiers, audio
converters, processors and switch mode power management.