A persuasive e-mail from an iPhone developer to Steve Jobs helped Pointy Heads Software get its Knocking Live Video—the first official iPhone app capable of streaming live video over 3G and WiFi connections—approved for sale in the App Store. The app relies on a private API—well-known among iPhone developers—to enable its video streaming feature, so its approval is a good sign for other companies developing video-based apps. It's also a good sign that Apple is taking developer complaints with the App Store approval process seriously.

Knocking Live Video uses an interesting take on streaming video. Unlike Qik, which is designed to stream video to multiple clients, Knocking streams from one iPhone to another. (It should be noted that the iPhone version of Qik wasn't approved with live streaming—it can only upload the video to Qik's website after recording for later streaming.) You simply launch the app and "knock" another iPhone user with Knocking Live Video installed. That user will receive the "knock" via push notification. Once answered, you can then stream live video directly to them. An iPhone 3GS or iPhone 3G is required to transmit video, but other iPhones and iPod touches can receive and view the stream via WiFi.

"We are focused on phone-to-phone, not uploading to the Web," Pointy Head developer Brian Meehan explained to Ars. "Who really cares about fleeting moments other than friends and family seeing it as it happens? With Knocking people share what they are doing right now. Our testers have referred to knocking as a 'visual tweet,'" he said.

To make its magic work, the app relies on use of a private API that enables capturing frames live from the iPhone's screen. "Our app uses a form of screen capture to create live moments which we have built a complex algorithm around," Meehan told Ars. However, use of private APIs—internal programming functions and methods that aren't approved for developer use—is a direct violation of Apple's iPhone developer agreement. It goes without saying that Knocking Live Video was promptly rejected about 30 days ago for violating this clause.

But Meehan was convinced that his app was worth fighting for. "When it was rejected, I decided not to give up and reach out directly to Steve Jobs via e-mail," he told Ars. "I reached out to Apple to reconsider our application due to its potential to culturally change how people share live moments phone-to-phone."

He made his case "in a way that was not about me or our app, rather about being a life-long user of all Apple products, about how I believed in Apple and that I believed Jobs would respond," Meehan said.

Meehan ended up composing a passionate plea to Apple's CEO, explaining he has been frustrated and disheartened with the app approval process, which often leaves developers wondering and waiting with little or no response from Apple about any potential problems. He pointed out that there are other apps that had been approved using the same private API call—though it was prior to Apple's suspected use of automated analysis software that can comb through code and spot references to unapproved APIs. Meehan even "humbly" requested that Jobs himself review a demo of the app and reconsider it for approval. He then fired off the e-mail to Jobs at 11pm on Saturday, November 21.

An Apple executive, who wishes to remain anonymous, contacted Meehan at 8:30am the following Monday morning to discuss the app and its rejection. He revealed that the order to reverse the app's rejection came "directly from the top." Within three hours of the phone call, Knocking Live Video was approved for sale via the App Store. The app is available for free starting today.

The approval is significant for several reasons. It's the first app with verified use of private APIs that Apple has approved for sale. It's also the first app approved to allow live video streaming. Finally, it's a concrete sign that Apple is indeed working to address developer concerns—though persuading Steve Jobs to personally approve an app is probably not going to become an official policy.

"Apple told me they are listening, and truly care about their developers and getting it right," Meehan said. "And I have to say I agree, as they reached back and it was a very positive experience," he told Ars.

The executive that Meehan spoke with didn't say if all apps using the particular API would now be eligible for approval—use of private APIs is generally frowned upon since they may change at any time and aren't guaranteed to work indefinitely. If Apple makes an internal change to iPhone OS, an app that uses a private API may suddenly stop working or start crashing. Given that Apple has been convinced that streaming video is a useful application for the iPhone, it will likely soon offer an approved API for screen capture or even accessing the iPhone camera's video stream directly.

Recently Apple SVP of worldwide marketing Phil Schiller tried to address concerns with the App Store approval process, echoing the sentiment that Apple is working hard to get things right. We noted at the time that saying it is one thing, and doing it is another. Reversing its decision to reject Knocking Live Video—like its recent reversal with Rogue Amoeba's Airfoil Speakers Touch—is an important step in the right direction.