The Sensoray Model 2253 is a USB-compatible audio/video codec that is capable of simultaneously producing two different video streams from a single composite video input and sending the streams out over USB. Powered from a single USB port, the unit measures 38 x 70 mm and consumers 1.5 watts, making it suitable for both portable and embedded applications.
One of the video streams may be a low-latency uncompressed stream (useful for real time previewing) and the other compressed, or both streams may be compressed. Image resolution is independently configurable for each stream, along with compression type and bit rate in the case of compressed streams. Video and audio are available as elementary streams or may be multiplexed in MP4 container format.
Up to 1024 bytes of application-supplied data may be inserted in the H.264 or MPEG stream, at a specified frame interval or as a one-time event. The Model 2253 implements hardware-generated timestamps to keep audio synchronized to the video, eliminating "lip sync" problems. Up to 80 characters of overlay text may be positioned anywhere in the video frame prior to compression. The unit supports H.264 HP@L3, MPEG-4 ASP and MJPEG for video compression as well as AAC and G.711 audio compression plus uncompressed PCM.
One general purpose digital input and one output are provided. The output is optically isolated, while the input may be either optically isolated or galvanically coupled. The input is sampled every millisecond, and when a state change is detected a notification is sent to the application program.
Support for image overlay on top of the compressed video, using images in Windows Bitmap (.bmp) or Portable Network graphics (.png) format with 24 or 32 bits per pixel and seven transparency levels, along with audio/video decoding from the USB port to the analogue output and low-latency preview are planned for future SDK versions.