Method for seamless splicing in a video encoder

• US 5,982,436 A
• Filed: 03/28/1997
• Issued: 11/09/1999
• Est. Priority Date: 03/28/1997
• Status: Expired due to Term

• Current Assignee: Pendragon Wireless LLC (Pendrell Corporation)
• Original Assignee: Philips Electronics North America Corporation (Koninklijke Philips N.V.)
• Inventors: Balakrishnan, Mahesh, Caron, Cedric
• Primary Examiner(s): LEE, RICHARD J
• Application Number:
  US08/829,124
• Time in Patent Office: 956 Days
• Field of Search: 348/12, 348/384, 348/390, 348/400-402, 348/409-412, 348/413, 348/415, 348/416, 348/419, 348/420, 348/423, 348/584, 348/699, 348/700, 348/845, 382/232, 382/236, 382/238
• US Class Current: 375/240.05
• CPC Class Codes: H04N 19/114 Adapting the group of pictures [GOP] structure, e.g. number of B-frames between two anchor frames H04N19/107 takes precedence
• CPC Class Codes: H04N 19/115 Selection of the code volume for a coding unit prior to coding
• CPC Class Codes: H04N 19/117 Filters, e.g. for pre-processing or post-processing sub-band filter banks H04N19/635
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/142 Detection of scene cut or scene change
• CPC Class Codes: H04N 19/149 by estimating the code amount by means of a model, e.g. mathematical model or statistical model
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/159 Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/177 the unit being a group of pictures [GOP]
• CPC Class Codes: H04N 19/40 using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream
• CPC Class Codes: H04N 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/23424 involving splicing one content stream with another content stream, e.g. for inserting or substituting an advertisement
• CPC Class Codes: H04N 21/2365 Multiplexing of several video streams
• CPC Class Codes: H04N 21/4347 Demultiplexing of several video streams
• CPC Class Codes: H04N 21/44004 involving video buffer management, e.g. video decoder buffer or video display buffer
• CPC Class Codes: H04N 21/44016 involving splicing one content stream with another content stream, e.g. for substituting a video clip

Abstract

A method of achieving seamless switching of digitally compressed signals. The method includes the steps of identifying the point in a video signal where splicing to a second video signal is desired, and thereafter, maintaining adherence to certain parameters in the encoder buffer to ensure that the input signal is not being compressed at a rate that causes either underflow or overflow in the encoder buffer. The method also includes the steps of constraining the upper bound of the encoder buffer to ensure that data is not being outputted from the encoder buffer to the decoder buffer too slowly so as to cause an underflow of data in the decoder buffer. The method may also include the steps of constraining the lower bound of the encoder buffer to ensure that data is not being outputted from the encoder buffer to the decoder buffer too quickly so as to cause an overflow of data in the decoder buffer.

Claims

1. A method of picture accurate splicing when the last picture in display order prior to a splice point is a B picture, said method comprising the steps of:

identifying the last picture in display order prior to a splice point;

changing the type of the identified last picture to one of an I or P picture;

determining the number of pictures in a current GOP containing the identified picture;

determining if the number of pictures in the current GOP is less than a threshold and if so, concatenating the current GOP with a previous GOP; and

terminating the current GOP with the identified picture if the splice point is a splice-in-point.

2. A method of picture accurate splicing when the last picture in display order prior to a splice point is one of an I or P picture, said method comprising the steps of:

identifying the last picture in display order prior to a splice point;

determining the number of pictures in a current GOP containing the identified picture;

determining if the number of pictures in the current GOP is less than a threshold and if so, concatenating the current GOP with a previous GOP; and

terminating the current GOP with the identified picture if the splice point is a splice-in-point.