
Functional Overview
1-7
1.2.6 Video Output
The L64021 provides a digitized video output for subsequent display.
This data is in the ITU-R BT.601 (Y, Cb, Cr) color space. The video
output operates with a luminance sample rate that is always exactly half
the device clock—nominally 13.5 MHz from a 27-MHz input clock. The
L64021 is always sync slave, and thus, it uses external sync signals to
synchronize the video display. The L64021 supports a number of trick
modes specic to the needs of DVD systems, including freeze frame,
skip B pictures, skip B and P pictures, and search for GOP.
1.2.7 Audio Output
The L64021 features both PCM DAC and S/P DIF interfaces. The serial
PCM DAC interface outputs two multiplexed channels of decoded MPEG,
Dolby Digital, or Linear PCM audio at a bit rate of 32 bits per sample for
each channel. It also supports a CD Bypass mode for direct output to
the PCM DAC interface or the S/P DIF interface.
The S/P DIF interface outputs S/P DIF formatted multichannel DTS (up
to 6 channels; L64021D only), Dolby Digital (up to 5.1 channels), and
Musicam (up to 7.1 channels) audio packets. It also outputs decoded
Musicam, Dolby Digital, or Linear PCM audio, which has been
downmixed to two channels.
The Audio Decoder module includes circuitry that maintains the correct
audio output sample rate based upon an external audio clock. The
decoder also provides an audio oversampling output clock to the external
audio DAC. This audio output clock is selected from one of the audio
clock inputs.
As shown in
Table 1.1, the S/P DIF interface for version L64021B packs
16-bits of Linear PCM data into IEC958 subframes at a sample rate of
48 kHz (input samples at 96-KHz are decimated to 48 kHz). The
L64021D enhances these features by adding 20- and 24-bit IEC958
subframe data width functionality at output sample rates of 48- or
96-kHz.