Try scheduling a recording, let it start, then look in the DCR-3250 web pages. I'm pretty sure you click on the tuner, and see the status of the channel.
Yeah. It's like an reskinned version of the old HDHomeRun pages.
I'm not 100% sure if the lineup.xml reports DRM channels with the Hauppauge device. Even if it did, the list could be out of date, requiring a rescan on the device. Either way, the tuner status page will tell us.
I rescanned the channels yesterday. 53 shows TCMHD but no DRM and no HD . I tried the http message in VLC, (1 or 2 frames again) then went to the system log on the 3250.
20200502-23:37:46 Tuner: tuner0 tuning 53 TCMHD (none:69MHz-13)
20200502-23:37:47 Tuner: tuner0 streaming http to 192.168.1.2:62754
20200502-23:37:47 CableCARD: tuner0 53 TCMHD (none:69MHz-13) access = subscribed
20200502-23:37:56 Tuner: tuner0 http stream ended (remote closed)
I stopped VLC then did it again
Given you're getting the same couple of frames in VLC, it's definitely all the device is delivering, so all NextPVR is going to get too. You might have to ring Hauppauge for more info. They might some more useful diagnostic steps.
I'm Guessing Spectrum changed the copy protection between April 4 and April 11. I'll check with them. Thanks for your help. I assume there isn't any legal way around this.