60fps Encoder (Axis Q7411)By: Ethan Ace, Published on Sep 07, 2012
Analog cameras support up to 30 frames per second yet Axis has announced an encoder that connects to them recording 60 frames per second. How is Axis doing that and what tradeoffs can you expect? In this note, we examine the features as well as up-the-coax PTZ control support, the unit's pricing and competitive positioning in the market.
The Q7411 is a single-channel encoder, similar to existing Q series encoders (multiple H.264/MJPEG streams, I/O, two-way audio, PoE), adding the following two standout features:
- High frame rate: The Q7411 supports framerates up to 60 FPS. Current and competitive models are generally limited to 30 FPS. The encoder uses a proprietary deinterlacing scheme to acheive this, that Axis claims improves image quality versus simply capturing every field as a frame. That said, we expect some video quality loss compared to a 'pure' 4CIF / 30fps stream, the only question is how much. Users should carefully consider this tradeoff and understand what impact it might have on their deployments
- Up-the-coax PTZ control: While existing Axis encoder models support PTZ control only via RS-422/485 serial output, the Q7411 now supports control up the coax. This simplifies control of PTZs using these protocols, which previously required converter boxes to translate serial output to up the coax commands. This feature may be found in some encoders from other manufacturers, but is often proprietary, working only with that manufacturer's own cameras.
The Q7411 is expected to ship in October 2012, and has an MSRP of $499.
60 FPS Options
The Q7511 is one of only a few products in the Axis line supporting 60 FPS framerate. Axis' Q6035 PTZ and 221 box camera support 60 FPS at 720p and 480x360 resolutions, respectively. Some competitive options are available which support these framerates, such as Basler (up to 100 FPS @ VGA) and IQinVision (60 FPS @ 720p), though it is not a common feature.
This is an expensive encoder and there's no point in using it unless you want the super high frame rate or want an Axis encoder that supports up-the-coax PTZ control. The most likely fit for the Q7411 is applications requiring high frame rate, such as casino or machine vision installations. Most applications use framerates in the range of 6-10 FPS, well below the capabilities of this encoder. Users connecting analog PTZs using up-the-coax protocols to an IP VMS may find the Q7411 of interest, as well, depending on Axis' protocol support.