We’ve been a big fan of Tablo since it’s Indigogo launch in 2013, and we were both pleased and a bit surprised to see the release of the 4th generation Tablo. We’ve been waiting for a next-generation Tablo since the Tablo ATSC 3.0 Quad was repeatedly delayed then effectively cancelled. The 4th generation Tablo follows in the footsteps of the Tablo Dual and Quad HDMI boxes. You can stream to mobile devices in the home, but these boxes don’t support Tablo Connect for out-of-home viewing. But it still has a trick or two up its sleeve making it a compelling product!
Since its first generation one of the hallmarks of Tablo was its ability to receive OTA television and stream it to mobile devices. In fact the first Tablos didn’t have HDMI outputs so if you wanted to watch shows on the big screen you’d need to stream them via a Fire TV or Google TV app. Later, Tablo also allowed viewing shows outside the home via Tablo Connect (though not on the Tablo Dual or Quad HDMI devices).
Mobile device and out-of-home streaming was accomplished by transcoding (converting) the as-broadcast shows into a format more appropriate for streaming. OTA shows are broadcast using the MPEG-2 video codec, which is a reflection of the time when the ATSC standard was created – back in the 90s. The Tablo models compatible with Tablo Connect convert these to H.264, a more modern codec which is achieves better compression. H.264 is also compatible with most mobile devices and required by Apple for streaming over cellular networks (MPEG-2 is not allowed). Particularly for Tablo Connect, Tablo boxes would record a few versions of a show with various qualities (resolutions and bitrates). This allows your mobile device to pick the most appropriate version based on the connection between your Tablo and your device.
Transcoding came compliments of the ViXS/Pixelworks chip powering Tablo. Sadly chips such as these have fallen by the wayside, and features such as Tablo Connect were casualties of their demise.
Antenna Amplification
One interesting feature of the 4th generation Tablo is its antenna amplification. As a general rule we’re not fond of receiver-side (as opposed to at-antenna) amplifiers. Whether the amplifier hurts or helps will depend on the strength of the OTA signals received by your antenna, and how your antenna is connected to the Tablo. Amplifiers inevitably add at least a little noise, so if you’ve got a strong but slightly noisy signal then amplifying it will likely hurt. But keep in mind that the signal is split inside the Tablo to feed two tuners, and a signal that worked fine on your TV’s single tuner may not suffice when split for two tuners. Check the signal strength reported by the Tablo to see if amplification is needed.
Assuming the signal strength for a station is weak, then amplifying the signal may help. The key is to not amplify the noise that is inevitably introduced in the cable between the antenna and amplifier – amplifiers can’t distinguish the OTA signal from noise and will amplify both. That’s why its a good practice to have the amplifier as close to the antenna as possible (some antennas come with built-in amplifiers). This is particularly true if there is a long cable run – for example dozens of feet – from the antenna. If your antenna is close to the Tablo then there’s probably little noise being picked up by the cable and the built-in amplifier will suffice. One thing to avoid is using both the internal amplifier and an amplified antenna – each amplifier introduces its own noise. A last word on signal strength, if you’re having problems receiving a channel with seemingly good reception interrupted by periodic pixelation, check to see if the signal strength is relatively stable. If its bouncing around then something is interfering with the signal – for example planes. They can either block the signal as they fly between you in the tower, or reflect an interfering signal. The same is true of cars, busses, and rats (yes, we had a signal problem that magically went away when we evicted the rats who’d taken up tenancy close to the attic antenna!)
Time-shifting FAST
One feature we’re thrilled to see in the new Tablo is the ability to time-shift FAST channels! OTT FAST channels look and feel like regular OTA broadcast channels – but don’t suffer from antenna issues since they’re broadband rather than OTA broadcast delivered. But since they look and feel like regular OTA channels they have the same problem of being linear – the broadcaster decides what’s on when and if you’re not around, well too bad. Tablo now fixes that in the same way DVRs did for broadcast TV!
Some previous reviewers have reported that you could record as many FAST channels simultaneously as you’d like. This makes some sense as the two-show limit for OTA is driven by the number of tuners. There’s no such hardware limit with FAST. However when we tried to record a third show we received a conflict message, so at least with the software version we tested on you’re limited to recording two FAST channels at a time. You can, interestingly, simultaneously record using the OTA tuners for a total of four simultaneous recordings. There are any number of reasons why the number of FAST channels that can be simultaneously recorded is restricted – management of broadband or hard drive bandwidth, for example. But unless the restriction is due to an internal processing limitation, it would be nice for the Tablo to measure bottlenecks during setup and adjust the number of simultaneously recordings accordingly.
We took a look under the hood to see what was being recorded and found what looked like MPEG2-TS HLS segments. The bitrate was roughly 4 Mbit/s, We also wiresharked the Ethernet connection and saw roughly 4 Mbit/s of traffic coming in, so as with OTA signals its likely that the Tablo is just recording the FAST channels as they are delivered by the streaming service. One question we have is whether adaptive bitrate (ABR) applies when recording a FAST channel, or if the Tablo always records a certain quality stream. With ABR you might see picture quality degrade a bit if your internet connection slows down, then pop back to a higher quality when things improve. Without ABR you always have the same quality, but if your internet connection slows down (or is simply too slow to begin with) playback will pause periodically. Worse, since we’re talking FAST channels, you may end up losing some of the stream.
At 4 Mbit/s the Tablo is probably recording one of the higher quality 1080p tiers…but what happens if your broadband connection slows down? Will it automatically switch to a lower bitrate? We’ll need to resurrect our ABR test setup at some point to look into this.
Power Consumption
The 4th generation Tablo is a fairly power-efficient box, consuming only 0.5 watts at idle. The power consumption does creep up as you start to to use external storage and ask it to record and play shows. .One oddity is that once we recorded a show we did not see the power consumption drop to pre-recording levels. We suspect that the tuner/demodulator was initially powered off, powered on for recording, but then left on. Whatever the case it’ll probably be addressed in a future firmware update.
Power consumption was measured at the wall with a WattsUp Pro watt meter.
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- Idle, Ethernet connected, internal storage amplification off
- Idle: 0.5w
- Ethernet connected, NVMe SSD in USB enclosure, amplification off
- Idle: 2.2w / 3.7w
- Watching one recording : 2.8w
- Watching two recordings : 2.9w
- Recording one OTA show: 3.1w
- Recording two OTA shows: 3.2w
- Recording two OTA and one OTT shows: 3.4w
- Recording two OTA and two OTT shows: 3.5w
- Recording two OTA and two OTT shows, watching one OTA show: 3.8w
- Wifi, NVMe SSD in USB enclosure, amplification off
- Idle: 2.7w
- Watching one recording :3.8
- Recording one OTA show: 3.5w
- Recording two OTA shows: 3.6
- Recording two OTA and one OTT shows: 3.9w
- Recording two OTA and two OTT shows:: 4.2w
- Recording two OTA and two OTT shows, watching one OTA show: 4.9w
- Idle, Ethernet connected, internal storage amplification off