Last week, I wrote about the many ways to get Internet video on your TV. Several readers asked how to do the opposite—how to view standard cable TV content, in real time, on a smartphone and tablet. So this week, I’m reviewing a new version of a familiar product that does just that.

It’s a new generation of the TiVo, the slick cable-TV box and DVR. Called the Roamio, it has the ability to stream live and recorded cable TV to an iPhone or iPad, without any extra hardware or adapters. For now, the Roamio can only stream to the two Apple devices when they are on your home network. But in October or November, the company will expand its streaming range, free of charge, so you can get cable TV on an iPhone or iPad, anywhere that has Wi-Fi.

I’ve been testing the new Roamio, which was introduced Tuesday—including a very early version of the out-of-home streaming feature coming in the fall. I also evaluated the Roamio’s new, faster user interface, better integration with services like Netflix, and greater recording and storage capabilities. But I focused on the streaming feature, which replaces an in-home-only streaming capability that required a $130 accessory.





The TiVo Roamio box, top, and the new TiVo app for iOS, above, lets users choose between watching shows on a TV or on an iPad. An Android version is in the works. The TiVo Roamio box, top, and the new TiVo app for iOS, above, lets users choose between watching shows on a TV or on an iPad. An Android version is in the works.

My verdict: The TiVo Roamio’s new cable-streaming features and improved software for Internet video come close to making it the only set-top box you need. But the out-of-home streaming feature doesn’t work for all cable networks and will need a lot of work to make its quality acceptable. Plus, the product is expensive for some budgets.

There are three models of the Roamio, but the base model, which costs $200, doesn’t include streaming and its DVR capabilities are similar to those of the prior TiVo model. The top two Roamios, the $400 Plus and the $600 Pro, have streaming and can record up to six shows at a time, compared with four shows on the base model. The only reason to prefer the Pro to the Plus is that it has triple the storage—up to 450 hours of HD programming, versus 150 hours.

In addition to the cost of the box, TiVo charges a $15 monthly service fee, which it compares to some cable companies’ DVR fees. You can get a lifetime subscription for $500.

While streaming is the big news here, it’s worth pointing out that, even without it, the TiVo could be considered the holy grail of set-top boxes. That’s because it combines the functions of a cable box, a DVR and a device for receiving Internet-video services like Netflix, Amazon, Hulu Plus and YouTube. You don’t need to change TV inputs or buy another box, like an Apple TV or Roku, to view these big four Web video services.

TiVo has had these Internet-video services for a while, but it presented them clumsily, in old versions and with a poor interface. With the Roamio’s new software, Netflix and YouTube are presented in an up-to-date way, and TiVo says it will be updating its presentation of the others as well, and adding more.

For my tests of the Roamio’s streaming features, I used an iPhone 5, an iPad Mini, and a full-size iPad with a high-resolution Retina display. I also used a test build of a revised TiVo app for Apple’s iOS mobile operating system that adds support for outside-the-home streaming. TiVo says an Android counterpart to this forthcoming iOS app will follow roughly six months later.

In my home, streaming from a Roamio Pro worked perfectly on all three devices, whether the program was live or recorded. Buffering at the start of the shows was over in a flash, video quality was very high and I didn’t observe any stuttering or stopping. Any live show you choose to stream gets recorded simultaneously.

But outside my home, streaming was a much different story. I tested streaming in five locations with public Wi-Fi: two Starbucks shops, a shopping mall food court, a Mexican restaurant and an Apple store. In every spot except the Apple store, which had an exceptionally fast connection for a public place, the TiVo streaming quality was terrible, almost unwatchable. Buffering was lengthy, video was fuzzy and stuttering and stopping frequent.

Granted, all the locations other than the Apple store had very slow Internet connections, generally under 2 megabits per second. But on other services like Netflix, video—sometimes even the same shows—came in fine at those locales.

TiVo acknowledges this situation but points out I was testing a very early version of the Roamio’s global streaming ability and the iOS app. It said the problems I ran into are the very reason it will need a few more months to refine the feature.

Another problem: Some premium networks, like HBO and Showtime, couldn’t be streamed out of the home. TiVo explains this is because of the networks’ polices, over which it has no control. But the TiVo app, like others out there, could include an authentication feature that would tell these networks you subscribe to them, which typically allows you to stream them to a mobile device.

There are other ways to get cable TV on a mobile device. You could buy a Slingbox. But that’s a $180 add-on device. Or you could get a Hopper with Sling technology built in, but that only works if you use the Dish satellite network. The TiVo Roamio works with multiple providers. There are apps that can stream cable TV video, sometimes even in real time, but many only stream live or recent shows from one network, or charge a monthly fee. The Roamio will stream many networks via one app and doesn’t charge extra for streaming.

If TiVo can fix the out-of-home viewing quality for slower connections, the Roamio would be a very good product for those willing to pay for it.

Email Walt at mossberg@wsj.com.