Electrical computers and digital processing systems: multicomput – Computer conferencing
Reexamination Certificate
1996-09-30
2001-01-16
Burgess, Glenton B. (Department: 2757)
Electrical computers and digital processing systems: multicomput
Computer conferencing
C709S227000
Reexamination Certificate
active
06175856
ABSTRACT:
BACKGROUND
In teleconferencing applications between computers that are coupled by a networking or communication medium, data is generally compressed. Data is compressed for a number of reasons, including bandwidth limitations in the networking or communication medium, the information rate of the processors providing data to the medium, and the number of processors (and by the number of processes on each processor) trying to send data to the medium simultaneously.
Unfortunately, a large number of compression algorithms and processes are available, complicating data communication. Because the computer systems which are coupled for teleconferencing need not be of the same type, nor even operate on the same platform, and frequently do not have common teleconferencing applications or other telecommunication applications available thereon, compatibility problems frequently arise. Selecting a data compression process or algorithm where several are available, that is compatible with at least one decompression process or algorithm on a remote processor can be problematic, especially given the fact that by definition data communication between the computer systems is not yet possible. Selecting a codec, or “compression/decompression” pair of processes, on remote processors can thus be difficult.
When an application detects a problem, in that the data being received is compressed and that no decompression algorithm or process is available on the current processor to decompress the data, the application generally either terminates, or alternatively, a receiving processor on which an application has difficulty decompressing data may send a signal to the transmitting processor indicating that a problem has been detected, and requesting that the transmitting processor switch to a different compression algorithm. Thus, the transmitting processor will switch to different compression process and the receiving processor will determine if the received data can be decompressed.
Although this hit-and-miss approach to codec negotiation is occasionally successful, the options become unmanageable as the number of codecs or the number of parties involved in a teleconference increases.
Therefore, a need has arisen for an automatic codec selector that determines what decompressors are available on each message recipient, determines what compressors are available on the current transmitting processor, and selects the best codec possible. The need is also arisen for a codec selector that automatically changes from one codec to another as new members join, or old members leave, a teleconference.
SUMMARY OF THE INVENTION
An apparatus, according to one aspect of the present invention, comprises at least two data compressors, each of which compresses data from a transmitting processor according to a particular compression process, and a selector which is coupled to receive information from a communication medium. The selector receives information from a receiving processor and selects one of the two data compressors based upon the information received from the receiving processor. The selector is typically coupled to at least one of the data compressors in order to select the selected data compressor. A communication port is coupled to the selected data compressor to allow the selected data compressor to provide compressed data for transmission.
A method, according to one aspect of the present invention, comprises receiving, at a transmitting processor, information from a communication medium which provides an identification of decompression processing capabilities at a receiving processor and selecting, at the transmitting processor, a particular compression process for use in compressing and transmitting data from the transmitting processor to the receiving processor through the communication medium.
In one embodiment, the communication medium may be considered to include a transmitting modem to phone-line to receiving modem connection without any conventional networking systems. In another embodiment, the communication medium may be considered to include a network system of computers with or without phone-line connections.
Another aspect of the invention comprises a computer readable medium, containing executable computer program instructions, in a digital processing system. The instructions when executed in the system cause the system to perform the steps of receiving at the system information from a communication port which identifies decompression processing capabilities and selecting, in response to the information, a particular compression process for use in compressing data for transmission. The particular compression process will typically be compatible with at least one of the identified decompression capabilities.
It will be appreciated that video compressors are usually different than audio compressors. Therefore, the compressor negotiation process of the present invention is typically repeated twice. That is, a process according to the invention is performed for video data, and then another process according to the invention is performed for audio data. The process may also be repeated again if other data (e.g., a text file), to be compressed by yet another compressor, is transferred between the participants in a teleconference. It will also be appreciated that these negotiation processes may be performed substantially in parallel in time or serially. For example, the receiving processor may transmit information concerning video and audio decompressors at the same time or at different times. If data files (e.g., a text file) are to be transferred, the receiving processor may also transmit information concerning decompression capabilities for such data files. It will be appreciated that the various compressors may be categorized into two categories: lossy and lossless. The video and audio compressors are often lossy, and the compressors for data files, such as text files, are lossless.
REFERENCES:
patent: 5206934 (1993-04-01), Naef, III
patent: 5546395 (1996-08-01), Sharma et al.
patent: 5557749 (1996-09-01), Norris
patent: 5587928 (1996-12-01), Jones et al.
patent: 5600646 (1997-02-01), Polomski
patent: 5621894 (1997-04-01), Menezes et al.
patent: 5742773 (1998-04-01), Blomfield-brown et al.
patent: 5859979 (1999-01-01), Tung et al.
International Telecommunication Union, “Draft ITU-T Recommendation H.245, Line Transmission on Non-Telephone Signals; Control Protocol For Multimedia Communication,” Nov. 2, 1995, pp. 1-189.
Apple Computer Inc.
Blakely & Sokoloff, Taylor & Zafman
Burgess Glenton B.
Kupstas Tod
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