Abstract: Possible overflow of a video buffer verifier (VBV) buffer employed in MPEG-like video encoders is prevented by controlling bits being drained from a video encoder buffer (eBuff). Specifically, a number of bits in the encoder buffer is determined when a last prior picture (pic n?1) ends, or when it should end. This number of bits (maxBits) is the maximum number of bits to be read from the encoder buffer and written to the remote decoder before a prescribed time T(n). When maxBits has been read from the encoder buffer and written to the decoder, the writing of bits to the remote decoder is stopped until the process is reset. If the prior picture ends early, maxBits is defined as being the number of bits in the encoder buffer at an expected time (Texp) that the picture should have ended less the number of bits written into the encoder buffer between the time the prior picture actually ended and the expected time for it to end, i.e., Texp. If the prior picture is late, i.e.

Abstract: Ensuring integrity of a video buffer verifier (VBV) employed in MPEG-like video encoders is realized by controllably adjusting the bits being drained from a video encoder buffer (eBuff). The number of bits being drained from eBuff is adjusted through feedback to minimize the difference in the bit content of a buffer (mBuff) maintained in a bit-rate controller in the video encoder that models the buffer of a hypothetical decoder, and the bit content of that hypothetical buffer (vBuff). Specifically, this is realized by controllably inhibiting transmission of bits from eBuff during intervals that the value of a prescribed relationship is greater than a predetermined value. In one example, the prescribed relationship is dependent on an instantaneous video encoding rate, an end-to-end delay, the bit content of mBuff and the bit content of eBuff.

Abstract: A transcoding method for inserting a visual element into an encoded bit stream with minimal decoding of the encoded bit stream. The transcoding method includes the steps of receiving an encoded bit stream containing a picture, partially decoding a copy of the bit stream, determining if a segment of the picture in the bit stream is affected by the insertion of the visual element, re-encoding the segment if the segment is affected by the insertion of the visual element, and outputting the re-encoded bit stream. The encoded and re-encoded bit streams may be MPEG-encoded bit streams. The re-encoded bit stream may be output using a bit rate control process that randomly selects an initial processing point within the re-encoded bit stream, requantizes the re-encoded bit stream using a modified quantization table, and/or utilizes a slice-level stopping criteria for selectively starting or ending bit rate control.

Abstract: Possible overflow of a video buffer verifier (VBV) buffer employed in MPEG-like video encoders is prevented by controlling bits being drained from a video encoder buffer (eBuff). Specifically, a number of bits in the encoder buffer is determined when a last prior picture (pic n-1) ends, or when it should end. This number of bits (maxBits) is the maximum number of bits to be read from the encoder buffer and written to the remote decoder before a prescribed time T(n). When maxBits has been read from the encoder buffer and written to the decoder, the writing of bits to the remote decoder is stopped until the process is reset. If the prior picture ends early, maxBits is defined as being the number of bits in the encoder buffer at an expected time (Texp) that the picture should have ended less the number of bits written into the encoder buffer between the time the prior picture actually ended and the expected time for it to end, i.e., Texp. If the prior picture is late, i.e.

Abstract: A transcoding method is performed by receiving a first bitstream of compressed image data having identifiable coding parameters. These parameters may relate to the GOP structure of pictures represented in the first bitstream, the size of the pictures represented in the first bitstream, whether the pictures represented in the first bitstream are field or frame pictures, and/or whether the pictures represented in the first bitstream define a progressive or interlaced sequence. First motion information is obtained from the first bitstream, and is used to extrapolate second motion information for a second bitstream of compressed image data. The second bitstream, which has one or more parameters different from the parameters of the first bitstream, is provided as a transcoded output.

Abstract: Frame dissimilarity measure (FDM) values are generated for pairs of frames in a video sequence that are separated by a specified timing window size, where each FDM value is the ratio of a net dissimilarity measure and a cumulative dissimilarity measure. In one embodiment, a first threshold condition is applied to identify peaks in the FDM data that could correspond to transitions between shots in a video sequence. A second threshold condition is applied to the FDM data adjacent to the detected peaks to identify frames at the start and end of the transition. The first threshold condition determines whether the FDM values exceed a first specified threshold level, while the second threshold condition determines whether the FDM values fall below a second specified threshold level. The net and cumulative dissimilarity measures may be based on histograms for the two frames.