Hi Frank,
I've been doing a bunch of testing with the LTC library, and I've noticed something. It works perfectly when playing audio over USB. But...less so when playing audio in via Line In on the audio shield.
Here's a link to a 1 minute file I have been testing with:
https://www.dropbox.com/s/7celrklbl9erhde/LTC_01_02_03_00__1mins_30.wav?dl=0
When I play this back via USB to the Teensy (3.2 for the moment) I can read the LTC and when I print it back via the serial port I see every frame, like this:
01:02:37.25
01:02:37.26
01:02:37.27
01:02:37.28
01:02:37.29
01:02:38.00
01:02:38.01
01:02:38.02
01:02:38.03
When I play back from the analog of my computer to the line in on the audio shield, I get this:
01:02:13.00
01:02:13.02
02:04:26.01
01:02:13.04
01:02:13.05
01:02:13.03
01:02:13.09
So clearly I'm not managing to decode each frame, and I get spurious misreads every once in a while.
I put a peak detector into my program so I can verify that both are coming in at the same level, and we are good there. I'm not exactly sure where to start on next. Any thoughts?
As I'm just using the decoder as a display for the moment the missing frames aren't the worst, I can't see individual frames anyway, they go by too fast. Those spurious reads way off in the middle of nowhere aren't great though, they cause the display to jump which is quite visible as a glitch.
Thank you!
I've been doing a bunch of testing with the LTC library, and I've noticed something. It works perfectly when playing audio over USB. But...less so when playing audio in via Line In on the audio shield.
Here's a link to a 1 minute file I have been testing with:
https://www.dropbox.com/s/7celrklbl9erhde/LTC_01_02_03_00__1mins_30.wav?dl=0
When I play this back via USB to the Teensy (3.2 for the moment) I can read the LTC and when I print it back via the serial port I see every frame, like this:
01:02:37.25
01:02:37.26
01:02:37.27
01:02:37.28
01:02:37.29
01:02:38.00
01:02:38.01
01:02:38.02
01:02:38.03
When I play back from the analog of my computer to the line in on the audio shield, I get this:
01:02:13.00
01:02:13.02
02:04:26.01
01:02:13.04
01:02:13.05
01:02:13.03
01:02:13.09
So clearly I'm not managing to decode each frame, and I get spurious misreads every once in a while.
I put a peak detector into my program so I can verify that both are coming in at the same level, and we are good there. I'm not exactly sure where to start on next. Any thoughts?
As I'm just using the decoder as a display for the moment the missing frames aren't the worst, I can't see individual frames anyway, they go by too fast. Those spurious reads way off in the middle of nowhere aren't great though, they cause the display to jump which is quite visible as a glitch.
Thank you!