elemedia® H.261 Soft-Codec

The Agora Labs elemeida H.261 Codec was originally developed at Lucent’s Bell Labs.  This codec supports both video frame sizes (CIF - 352x288 and QCIF - 176x144). It was designed to operate over ISDN or IP networks for video telephony and videoconferencing, and used a bandwidth of at least 40 kbit/s but no more than 2 Mbit/s.  It is required to be in all H.323 systems that support video (although this requirement is sometimes violated).

The H.261 specification defines how to decode the video stream, the H.261 encoder is left up to the developer's discretion.  Agora has made many improvements to the encoder in order to improve the viewer's experience of the picture.  For example, on limited bandwidth, low performance systems, the H.261 library has a way to assign importance to each pixel based on an average user's perception.  These pixels are given higher precedence and will be discarded last if all the data does not fit in the channel.

H.261 can run on IP networks, and the Agora elemedia H.261 codec can output packets that conform to RFC 2032, "RTP Payload Format for H.261 Video Streams. "  Agora's RTP stack also supports RFC-2032.  If you use both Agora's H.261 codec and Agora's RTP/RTCP stack, your integration task becomes easier.

The H.261 encoder operates in real-time because it is used in videoconferences and videophone calls.  The Agora H.261 codec library is fast and memory efficient, suitable for use in large servers and the smallest endpoints.

Agora Labs is a premier H.261 codec IP stack module supplier, providing a video codec that has a small footprint and is fast.  Agora prides themselves on their support which is unparalleled.  Please contact us for more details.

The elemedia H.261 SDK is available as a binary module for use by system developers.  It has been used in many systems, including Windows servers and workstations, and Linux servers and workstations.  An H.261 .DLL is available off-the-shelf.