I understand the PCR field in mpeg-2 ts adaptation field is 42 bits wide. 33 bits for the 90 kHz base, and the 9-bit 27 MHz extension.
The 27 MHz clock will churn out 0 - 299 over and over again at a rate of 27 Mhz. And each time a "rollover" occurs from 299 to 0, then the 33-bit (90 kHz) counter is incremented.
I understand the PTS/DTS are generated from these 33-bit values.
What I don't understand is this: What is meant by "extension bit". What's being extended? And I would love to see some examples of this 42 bit value. I need to see some examples so it can become clear. How is this 42 bit value used? How are the 33-bit and 9-bit values used and what do they look like? Never seen them before, I just read this is what they do so I really need practical examples.
Thank you so much!!!
Think of an analog clock with a second and a minute hand. Every minute the second hand ticks off 60 times, then the minute hand ticks off once, and second rolls back to zero. This is the same. Every second the 27Mhz hand tick 300 times, the the 90khz hand ticks off once, and the 27Mhz hand rolls back to zero. 300 * 90000 = 27000000 Every number between 0 and 2^42-1 is a valid example.