Non-seamless splicing of audio-video transport streams

DETAILED DESCRIPTION The present invention provides a method and apparatus for splicing multiple transport streams.
The stream insertion operation is entirely digital and utilizes the flexibility of current digital audio-video coding standards to provide non-seamless splicing which is generally acceptable to most viewers.
The invention is particularly well-suited for use with MPEG-2 compliant transport streams.
In accordance with one aspect of the invention, a method of splicing transport streams is provided.
The method includes the step of ensuring that a designated frame of a first transport stream will have a predetermined frame characteristic.
The designated frame is the final first transport stream frame to be displayed before display of a second transport stream to be spliced with the first transport stream at a splice point.
A frame with the predetermined frame characteristic may be a black frame.
The method also includes the step of outputting transport packets having a predetermined packet characteristic in place of transport packets of the first stream for a period of time after the splice point.
This period of time is greater than the splice decoding delay associated with the splice point.
Packets with the predetermined packet characteristic may be null packets.
The exemplary method concludes with the step of outputting transport packets of the second transport stream.
The step of ensuring that the final first stream frame has the predetermined characteristic may be implemented by a digital stream insertion device inserting a black frame followed by an end-of-sequence (EOS) code into the first stream.
Alternatively, the step of ensuring that the final first stream frame has the predetermined characteristic may be implemented by an encoder forcing the final first stream frame to black during an encoding operation, with a corresponding EOS code inserted either by the encoder or the digital stream insertion device.
In accordance with another aspect of the invention, an apparatus is provided which includes a packet filter having a first input corresponding to a first transport stream and an output corresponding to splice point data associated with the first input stream