I’ve had a legacy 4-tuner Tablo for several years. I have a good RCA antenna with long rabbit ears so I can get Channel 6 ABC in Philadelphia which broadcasts on Low VHF channel 6 (yes, I’m sure that is the correct RF channel).
I record the 6am news every morning. The last few days, the recordings are all working, but thumbnails are failing to generate. Thumbnails are being generated on recordings on all other channels. Typically when thumbnails aren’t being generated it means that the signal isn’t strong enough or the Tablo thinks something is amiss with the recording and can’t make the thumbnails. So next up I re-oriented the antenna by moving the rabbit ears, and checking that I still get 5-green-dots on channel scan for the channels I watch.
Still no luck. I’m debating about doing a factory reset, which I only give a 10% probability of actually fixing the problem.
So my main question for you helpful folks is to find out if anybody else is having a similar issue. My best guess is Channel 6 lowered the power on their signal recently.
Also, before I do a factory reset, does anybody think that would help? Luckily I don’t have any stored recordings and I don’t have a lot of scheduled programs to re-enter, so it won’t cost that much in time and effort if I give the factory reset a shot.
I know that ABC in Philly is a challenge because they are Low-VHF, but it sound like you have that under control.
I have noticed that I have a few channels that don’t generate thumbnails. But, mine are low-resolution channels showing sitcoms in 480i. One commonality that I have found is that those stations are also broadcasting in MPEG-4. Can’t say for sure it is the issue, but they do have that in common. Other 480i stations do not have this problem.
6-ABC is 720p. Good point on stations that are also broadcasting in MPEG-4 (that is NextGenTV or ATSC 3.0). A quick check confirms that 6-ABC is now broadcasting in ATSC 3.0 as well. That lends more weight to the theory that they are messing with the ATSC 1.0 signal.
I’m about to try a factory reset since the family is out for a few hours. Even if it doesn’t fix the thumbnail problem, it is probably a good idea to clean out the crud with a factory reset every year or so.
Keep in mind, a full factory reset will loose all your preferences, recording schedules, saved channels…everything. It also wipes out the logs, so if you want Tablo to look into the problem all that information will be gone.
I’m not telling you to not do it, I just want you to be aware of the implications.
Thanks for the heads up…I did know those pitfalls you pointed out, but for casual readers of this forum it is great advice. Maybe I should add “Warning: Factory resets are not for the faint of heart…do not try this at home!”
I used antennaweb.org and put in my address. They have “NextGen TV” info. I am making an assumption that NextGen TV is MPEG-4, and I could be wrong about that.
I just got done with the factory reset, and not surprisingly, still no thumbnails on 6-ABC. I forgot what a pain it is to find the Tablo on my network (I’m using WiFi because I don’t have ethernet in the spot I want to keep the Tablo). I have to use the Tablo mobile app which I had to add to my phone to get the job done.
MPEG 4 isn’t only used for ATSC 3.0. There are many types of MPEG4. ATSC 3.0 typically uses HEVC (similar to BluRay discs), which has very high compression. There are many ATSC 1.0 channels that use AVC (from DVD’s), which is a simpler compression.
One of the “benefits” of ATSC 3.0 is 4K. And for that, stations would use HEVC (and AC4, important). While certainly another benefit of ATSC 3.0 comes with reception benefits, if 4K is “the thing”, that’s going to be HEVC + AC4.
I know the “possibilities” are out there for doing such without HEVC, but I see the alternatives as being very unlikely in deployment.
But, IMHO, we need to take this all “out of here” because DVR as we know it, right now, is dead from the start with ATSC 3.0 due to the anti-consumer restricted rights drm they are mandating.
We took a look and noticed the 6-1 broadcasts are in an MPEG-4 format with variable framerates.
Tablo does not currently expect MPEG4 broadcasts to be encoded with variable frame rates. For this reason, recordings from stations broadcasting with those specific parameters will fail to generate fast-forward previews.
We’re going to fix this in a future firmware update.
You gave me an idea…I went to Settings->Recording Quality and changed the setting from “HD 1080 - 10Mbps” to “HD 720 - 5Mbps” and now recordings on channel 6-1 are generating thumbnails!
Since the station is broadcasting in 720, there is no loss in quality of the recording.
