Abstract: The present invention provides methods and apparatus for dynamically adjusting f-codes for a digital picture header of a coded picture. A video encoder having at least one motion estimation stages is provided for encoding the current picture. Motion vectors are determined for one motion estimation stage of the encoder. The motion vectors are analyzed to determine a maximum motion vector range for the picture. A corresponding minimum f-code is determined for the maximum range. The minimum f-code is then inserted into the digital picture header. In this manner, the f-codes carried in the digital picture header can be reduced to the minimum required value, thus reducing the number of bits needed to encode the f-codes.

Abstract: A method (60) and apparatus process video in a multiple encoder system by identifying (61) those frames that were originally encoded as anchor frames in the first encoder and ensuring that the second encoder (e.g., the re-encoder) encodes (65) these identified frames as anchor frames rather than bidirectional frames or non-anchor frames. In addition, the second encoder identifies (62) those frames that were originally encoded as non-anchor frames in the first encoder and encodes (66) the non-anchor frames, such as bidirectional frames, as non-anchor frames during the second encoding process. Once the anchor frames (and non-anchor frames) are identified, the present invention also determines (63) a frame-type pattern output by the first encoder and synchronizes (64) the second encoder to the identified frame-type pattern of the first encoder, thereby ensuring optimal utilization of encoder resources. A method for determining frame type (80) based on relative spatial activity is also set forth.

Abstract: Method and apparatus for processing transport stream packets received from a network for distribution to user terminals is described. In one embodiment, a pair of clock reference packets in the transport stream packets is identified. The pair of clock reference packets includes a first clock reference packet having an output time stamp and a second clock reference packet. A difference between a time value of the second clock reference packet and a time value of the first clock reference packet is computed. An output time stamp for the second clock reference packet is calculated in response to the output time stamp of the first clock reference packet and the difference.

Abstract: A method (30) for a converting a DS3 transport stream to MPEG-2 packets over an ASI transport stream includes: extracting (31) MPEG-2 packets along with PCR values; calculating (27) a new PCR value to compensate for packet time shift; and replacing (28) the extracted PCR value with the new PCR value prior to outputting MPEG-2 packets. The method (30) also includes outputting (28) the MPEG-2 packets over the ASI transport upon arrival in the DS3 transport stream in a bursty manner without storing them in a buffer, but rather only storing (36) extracted PCRs in memory, delaying (33) output of MPEG_2 packets over the ASI transport while adjusting PCRs; generating (37) a timing signal (TS_pkt) indicating a time that an MPEG-2 packet arrives; generating (39) a timing signal (TS_info) indicating a time that an MPEG-2 packet should be output over the ASI transport, and calculating PCR_new=PCR_old+(TS_pkt?TS_info) in which PCR_new is a new PCR and PCR_old is an extracted PCR.

Abstract: A method and apparatus for processing a bitstream in a digital video transcoder is described. In one example, an adjustment factor is determined that relates a number of bits representing a selected frame defined by the bitstream to a target number of bits for the selected frame. An average spatial activity value among sets of video data is associated with the selected frame. A spatial activity value for a selected set of the sets of video data is determined. A normalized spatial, activity value for the selected set of frequency video data is then computed in response to the average spatial activity value, the spatial activity value, and a function of the adjustment factor. Target bit reduction for each of the sets of video data may be computed using a function of the normalized spatial activity value and the adjustment factor.

Abstract: The present invention provides improvements of the rate control method during the transitions at the splice point. In one embodiment, black frames and/or mute audio frames are inserted at the splice point.

Abstract: An efficient statistical remultiplexer for processing a number of channels that include video data. In one aspect, transcoding of the video data is delayed while statistical information is obtained from the data. Bit rate need parameters for the data are determined based on the statistical information, and the video data is transcoded based on the respective bit rate need parameters following the delay. In another aspect, a transcoding bit rate for video frames is updated a plurality of times at successive intervals to allow a closer monitoring of the bit rate. Minimum and maximum bounds for the transcoding bit rate, e.g., for buffer overflow and underflow protection, are also updated in each interval.

Abstract: A method for editing spliced-together video comprising a cut-out sequence followed by a cut-in sequence, both being in 3:2 pull-down format. A bad edit is detected, and either a number of contiguous frames at the end of the cut-out sequence and/or a number of contiguous frames at the beginning of the cut-in sequence are deleted in order that the 3:2 pull-down sequence is preserved in the spliced-together video. Alternatively, a first number of frames at the end of the cut-out sequence and/or a second number of frames at the beginning of the cut-in sequence are copied/renamed and inserted from other fields in order that the pull-down format is preserved in the spliced-together video.

Abstract: A system and method for audio splicing (insertion) of an Ad audio stream in the compressed domain, where variable early delivery of the Ad audio stream and variable bit rate are allowed, without creating audio distortion, glitches, or other digital artefacts or errors, in the resultant audio stream is disclosed. The present system and method provides for a splice delay buffer which delays the first five Ad audio frames until transmission of the last frame of the primary audio stream, but before the splice time. Subsequent Ad audio frames are delayed by a fixed amount, where the fixed amount is greater than the frame delay of the primary audio stream, to allow for ease of splice back to the primary audio stream.

Abstract: An encoder and encoding method for inserting logos into a digital television signal. The logo insertion is performed at the front end of the encoder (e.g., prior to compression) by sharing the video capture frame buffer of the encoder, so there is no need for a separate logo inserter with a separate buffer, and encoding cost are reduced. An alpha blending function receives logo image and logo alpha map data for blending with input video data. The input video is retrieved from the frame buffer, and written back to the frame buffer after blending with the logo data. Subsequently, the frame buffer contents are provided to a pre-processing function for filtering and film mode detection. For a film mode frame, a drop field decision is provided from the pre-processing function to the frame buffer to drop the redundant field. The pre-processed video data is then provided for conventional compression processing. In an HDTV embodiment, several compressors are provided which each receive a panel of a video frame.

Abstract: A system for processing a sequence of video or other data frames at a data encoder during a sync loss. During a sync loss of input data at a video or other data encoder, substitute data such as black video is used to provide complete “clean” data frames to a compressor at the encoder. Artifacts due to compression and encoding of partial frames are avoided. If a sync loss is detected in the middle of a particular data frame that is input to the encoder, the remainder of the frame is completed with substitute data which is in sync with the earlier data in the frame. Additional complete frames of the substitute data are provided to the compressor following the particular data frame, still in sync with the particular frame, until such time that a sync recovery is detected, and a field or frame check is performed on the new, post-sync loss, data to gain confidence of the sync recovery.

Abstract: A method and apparatus for efficient motion estimation of a digital video image wherein memory capacity and processing requirements are reduced by 50% or more, and image quality is maintained. Only a portion of the pixel data of a search window is used to perform motion estimation. Specifically, a portion of the pixel data of a previous image is retrieved and stored in a memory according to a search window pattern such as a fixed checkerboard pattern. Pixel data from the current image is alternated between first and second inverse checkerboard patterns for successive comparison regions of the search window. The scheme is compatible with frame or field mode video sequences.

Abstract: A current pixel of a video image is adaptively filtered to provide stronger filtering when there is a high likelihood that noise is present. Weaker filtering is provided when the presence of a color and/or brightness edge is likely in the video image. Each pixel has luminance and chrominance amplitude values. In a filtering method, a current pixel is intermediate to first and second pixels in the video frame. Difference signals are determined based on the amplitude difference between the current pixel and first and second adjacent pixels. A plurality of available filters provide successively stronger filtering of the current pixel amplitude. One of the filters is selected for filtering the current pixel according to the difference signals. Secondary difference signals which indicate the amplitude difference between the current pixel and pixels which are adjacent to the first and second pixels are also considered in the selection process.