Showing papers on "Residual frame published in 1997"

Rate control for stereoscopic digital video encoding

Abstract: Rate control in a stereoscopic digital video communication system is accomplished by modifying the quantization level of P or B-frame data in the enhancement layer depending on whether the frame is temporally predicted (from the same layer) or disparity predicted (from the opposite layer). The invention can maintain a consistent image quality by providing additional quantization bits for disparity-predicted P-pictures, for example, where a P-frame may be encoded from a B-frame in the enhancement layer. The selected quantization level corresponds to an overall bit rate requirement of the enhancement layer. For disparity predicted P-frames, the quantization step size is modified according to the activity level of the frame being encoded in the enhancement layer, or of the reference frame, whichever is greater. Also, image quality is improved and frame freeze up is prevented during editing modes such as fast forward and fast rewind which require random access to the picture data. When the reference frame in the base layer is the first frame of a group of pictures (GOP), the corresponding enhancement layer frame will be encoded as an I or P frame instead of as a B frame to improve image quality and eliminate or reduce error propagation during random access.

Method and apparatus for transitions and other special effects in digital motion video

Abstract: A method and apparatus for transition effects in digitally compressed motion video, such video complying with the MPEG-1 standard. Transitions between two frames of video are effectuated by selecting a FROM frame and a TO frame, generating a stream of bidirectionally dependent duplicator frames which vary in their motion vector references to the FROM frame and the TO frame according to a predefined pattern, placing the FROM frame in the past buffer of a decoder, placing the TO frame in the future frame of a decoder, feeding the stream of duplicator frames to the decoder, causing the duplicator frames to be displayed, and beginning normal playback of the video stream containing the TO frame at the TO frame position.

Simultaneous cut through and store-and-forward frame support in a network device

Abstract: A method and system are provided for enabling simultaneous cut-through and store-and-forward transmission of frames in high speed network devices. A Buffer Parameter Vector chains multiple frame buffers together. Frame Parameter Vectors created for each unique version of a frame are used to manage frames as they flow through the network device. Cut-through/store-and-forward decision logic determines whether frames can be transmitted by cut-through or store-and-forward. Multiple unique frames or copies of a frame that are to be transmitted store-and-forward have their Frame Parameter Vectors chained together by pointers. The cut-through/store-and-forward decision logic steps through the chain of Frame Parameter Vectors resulting in the frames associated with each Frame Parameter Vector being transmitted.

Source model for transform video coder and its application. II. Variable frame rate coding

Abstract: In the first part of this paper, we derived a source model describing the relationship between bits, distortion, and quantization step size for transform coders. Based on this source model, a variable frame rate coding algorithm is developed. The basic idea is to select a proper picture frame rate to ensure a minimum picture quality for every frame. Because our source model can predict approximately the number of coded bits when a certain quantization step size is used, we could predict the quality and bits of coded images without going through the entire real-coding process. Therefore, we could skip the right number of picture frames to accomplish the goal of constant image quality. Our proposed variable frame rate coding schemes are simple but quite effective as demonstrated by simulation results. The results of using another variable frame rate scheme, Test Model for H.263 (TMN-5), and the results of using a fixed frame rate coding scheme, Reference Model 8 for H.261 (RM8), are also provided for comparison.

Multi-code compressed mode ds-cdma systems and methods

Abstract: Introduction of discontinuous transmission in CDMA communications techniques is achieved by selectively using additional spreading codes for spreading a frame of data. By dividing a frame into two or more portions and spreading each portion with a different spreading code, the frame can be transmitted in a compressed mode wherein the information is transmitted during a portion of the frame period, leaving an idle part of the frame in which to perform other functions, such as evaluation of other frequencies for use in handover between frequencies.

Code-rate increased compressed mode ds-cdma systems and methods

Abstract: Introduction of discontinuous transmission in CDMA communications techniques is achieved by using selectively puncturing coded output of a convolutional encoder. By temporarily increasing the coding rate during a frame, information only fills an information part of a frame in a compressed mode, leaving an idle part of the frame in which to perform other functions, such as evaluation of other frequencies for use in handover between frequencies.

Global motion estimator for motion video signal encoding

Abstract: A transformation filter estimates global transformation parameters between a current frame and a previous frame of a motion video image according to corresponding relative positions of pixels within the two frames. Such estimated global transformation parameters estimate global translation, rotation, and scaling resulting from camera pan, rotation, and zoom. The current frame is transformed according to the estimated transformation parameters. As a result, the transformed current frame more closely correlates with the previous frame and motion compensated compression provide better compression and reduced distortion simultaneously. The transformed current frame is encoded using entropy-constrained vector quantization (ECVQ) using quadtrees for variable block sizes within the representation of the current frame. Such quadtree ECVQ is improved significantly when the single frame is first globally transformed in accordance estimated transformation parameters between the single frame and the previous frame. As a result, larger block sizes can be used more efficiently when differences between the current frame and the previous frame are due primarily to camera pan, zoom, and/or rotation. Of course, when significant differences between the frames are due primarily to motion in the subject matter of the motion video image, smaller frame sizes adapted through ECVQ quadtree encoding still reduce the size of the encoded frame without unduly sacrificing motion video image quality.

Adaptive field/frame encoding of discrete cosine transform

Abstract: A method of Discrete Cosine Transform compression of a digital video image. In the method the Field Variance and Frame Variance are calculated. When the Field Variance is less than the Frame Variance, Field Discrete Cosine Transform type compression is performed. Alternatively, when the Frame Variance is less than the Field Variance, then a Frame Discrete Cosine Transform compression is performed.

Rate-distortion optimized frame type selection for MPEG encoding

Abstract: We present an algorithm for joint optimization of anchor frame separation and bit allocation for motion-compensated video coders. The anchor frame separation is optimized in the sense that the distortion is minimized under a bit budget constraint. At the same time, the quantization for each frame in a group of pictures is also optimized in an operational rate distortion sense. The optimal anchor frame separation does depend on the quantization of each frame so that the two optimization problems cannot be separated. A Lagrange multiplier approach can be used to obtain the optimal solution if we assume that the rate-distortion curve is convex. Heuristic algorithms based on simulated annealing and greedy trellis selection are also presented to reduce the computational complexity.

Video encoder for digital video displays

Abstract: An improved multimedia encoder having features advantageous for use in a computer system. These features provide for the reduction of bandwidth and storage requirements, the enhancement of noise immunity, the evening of computational loading, and the use of multimedia drives for general purpose data storage. In one embodiment, the encoder receives image data representing a sequence of video frames and display text data representing a sequence of text fields to be overlaid on the sequence of video frames. The multimedia encoder produces a compressed video frame only for each subsequent video frame which is different from the current video frame. After each video frame is compressed, it becomes the current frame. The multimedia encoder provides error correction encoding to enhance noise immunity, and performs interframe compression using a dynamic search area to even out computational loading. Additionally, the multimedia encoder allows text file storage using a sub-picture unit bitstream and direct binary file storage, thereby enabling a write-able multimedia disk to displace a hard disk drive. A companion multimedia decoder recognizes these features and decodes a multimedia bitstream accordingly.

Temporal compression and decompression for video

Abstract: A temporal compression and decompression system is disclosed for color video. A video stream with red, green and blue pixel element values is input to a first computer. In the first computer, a new frame of video data is compared to the frame being displayed on a second computer and the similarity between corresponding blocks and sub-blocks is represented with one tolerance result per sub-block. Based on the number of sub-blocks for which tolerance results exceed a preset threshold and a user-specified quality level, an update quality level is selected that determines the quality at which the frame update is transmitted from the first computer to the second computer. Before the frame update is transmitted the updating information is compressed in a two-stage process. In the first stage 5-bit red, blue and green element values in sub-blocks being updated are is converted to 3-bit categories. In the second stage groups of categories are converted to variable-length Huffman words. The Huffman words are then transmitted over a communications channel to the second computer, which decompresses and displays the updated sub-blocks.

Bandwidth and frame buffer size reduction in a digital pulse-width-modulated display system

Abstract: Method and apparatus for converting a stream of incoming serial video data which is received frame by frame and is formatted with all data bits arriving together for each pixel into digital PWM video as a sequence of likeweighted bits. Incoming video data is temporarily stored in a digital memory. A controller organises the data in the memory into a plurality of buffers, each buffer having only bits of like weight. The data is collected as groups within the buffers. The data is then coupled to a display device as the groups of likeweighted bits. As groups of the shortest durationbit weight are formed, they are coupled to the display and thus need to be stored only for the fraction of a frame time. Therefor the size of the buffer requied for storing the video data for PWM is less than an entire frame.

Displaying film-originated video on high frame rate monitors without motions discontinuities

Abstract: In arrangements for the frame rate upconversion of motion-picture-source video, a 60 Hz (interlaced field rate or progressive scan frame rate) television signal is converted to a form suitable for display on a variable-frame-rate high-resolution progressively-scanned monitor of the type typically associated with a computer or with a television set employing an increased frame rate. The inherent 3-2 motion picture film pulldown pattern in the source signal is changed to an equal time frame pattern, such as 3-3, 4-4, or 5-5, when the source signal is converted to a higher frame rate. This may be accomplished when the increased progressively-scanned video display frame rate is an integral multiple of the motion picture frame rate, namely 72 Hz, 96 Hz and 120 Hz.

Video frame synchronization of independent timing generators for frame buffers in a master-slave configuration

Abstract: A method and apparatus for synchronizing the vertical blanking of multiple frame buffers which may exist on the same computer or separate computers for certain applications including stereo display, virtual reality and video recording, which require such synchronization. To obtain the required synchronization one frame buffer is designation as the master. It provides a signal called FIELD that changes state (0 to 1 or 1 to 0) at the start of every vertical sync event on the master frame buffer. All other frame buffers are set to be slaves. Their timing generators sample the master's FIELD signal. When they detect the master's FIELD signal changing state, they set their own internal timing to match to thereby achieve frame synchronization.

Video capture device with adjustable frame rate based on available bus bandwidth

Abstract: An image acquisition apparatus, for acquiring frames of a video signal and storing these frames in a computer memory, is disclosed. An analog video input signal, comprising a sequence of video frames, is digitized by an A/D converter. The resulting digitized frames are selectively gated into a frame acquisition buffer. The frame acquisition buffer includes two or more memory segments, each configured to store a digitized video frame. A DMA controller transfers video frames from the frame acquisition buffer to the computer memory via a peripheral bus. Frame acquisition control logic (e.g. a second DMA controller) selects which video frames of the frame sequence are to be acquired into the frame acquisition buffer. The frame acquisition control logic and the DMA controller are coordinated by a status memory which contains a status flag for each memory segment. The frame acquisition control logic: checks a status flag to ensure that the corresponding memory segment is available before commanding the memory segment to be overvritten with a new video frame; and changes the status flag to indicate unavailability. The DMA controller updates a status flag to indicate availability when it finishes transferring the data contents of the corresponding memory segment. The frame acquisition control logic and the DMA controller operate concurrently.

Apparatus and method for processing groups of fields in a video data compression system to encode a single frame as an I-field and a P-field

Abstract: A video compression system which is based on the image data compression system developed by the Motion Picture Experts Group (MPEG) uses various group-of-fields configurations to reduce the number of binary bits used to represent an image composed of odd and even fields of video information, where each pair of odd and even fields defines a frame. .[.According to a first method, each field in the group of fields is predicted using the closest field which has previously been predicted as an anchor field. According to a second method, intra fields (I-fields) and predictive fields (P-fields) are distributed in the sequence so that no two I-fields and/or no two P-fields are at adjacent locations in the sequence. According to a third method, t.]. .Iadd.T.Iaddend.he number of I-fields and P-fields in the encoded sequence is reduced by encoding one field in a given frame as a P-field or a B-field where the other field is encoded as an I-field and encoding one field in a further frame as a B-field where the other field is encoded as a P-field.

System and method for performing high-precision, multi-channel blending using multiple blending passes

Abstract: A high-precision multi-channel blending operation replaces a single pass blending operation to overcome distortions resulting from an insufficient number of bits available per pixel in a hardware frame buffer. A desired frame buffer configuration, with a fewer number of channels, and a larger number of bits available per channel than available for a single pass blending operation, is specified and allocated in memory. The same, fewer number of channels from a destination image are written into the frame buffer. The frame buffer is configured for blending, and the same, fewer number of channels from the source image are blended into the frame buffer. The contents of the frame buffer is written into a memory location. The above steps are repeated, until all of the channels have been blended and written into different parts of memory. The channel information from the memory locations are combined to form an image having a user-desired bit resolution.

Method and apparatus for table-based compression with embedded coding

Abstract: The present invention provides, in one aspect, a computer-implemented method for encoding video data that includes a first frame and a subsequent frame. The first frame is segmentable into at least one first block, and the subsequent frame is segmentable into at least one subsequent block. The method involves obtaining the first frame, and obtaining the subsequent frame in luminance and chrominance space format. A motion analysis is then performed between the subsequent frame and the first frame, and the subsequent block is encoded. Encoding the subsequent block involves using an encoding table generated from an encoding codebook which is designed using a codebook design procedure for structured vector quantization.

Method and apparatus for encoding high-fidelity still images in MPEG bitstreams

Abstract: A frame in an uncompressed digital video signal is selected for encoding as a high-fidelity still image. The digital video signal is MPEG encoded to produce an MPEG encoded bitstream and additional bits are employed to encode the selected frame, to produce the MPEG encoded bitstream. The additional bits are determined by fixing the values of MQUANT and "intra DC mult" for all macroblocks in the selected frame. In an alternative method, the extra bits are determined by repeating the selected frame a plurality of times in the digital video signal prior to encoding the selected frame.

Multicast frame support in hardware routing assist

Abstract: A method and system are provided for increasing processing efficiency associated with data frames transiting a network node having multiple ports. The method and system accomplish their objects via the following. A data frame having a header and data is received. An associated pointer for at least one portion of the received data frame is provided. The associated pointer is provided by segmenting each received data frame into parts, and associating with each segmented part a pointer. Thereafter, a portion of the received data frame is modified independent of other portions of the received data frame via utilization of given one or more of the associated pointers. Additionally, one or more copies of a portion (which can include the whole) of the received data frame is constructed by recalling each segmented part associated with one or more selected ones of the associated pointers. Furthermore, a determination is made as to whether the received header indicates unicast or multicast. In response to this determination, a number of data frames are constructed commensurate with protocols and destination addresses of one or more network nodes to which the constructed number of data frames is to be transmitted. The constructed data frames are transmitted from the node.

System, arrangement, and method for replacing corrupted speech frames and a telecommunications system comprising such arrangement

Abstract: A system and method are provided for improving speech quality for signals divided into a frame structure. Speech information in a signal is detected, and a lost or corrupted transmitted frame is detected. The lost or corrupted frame is replaced by a suitable frame if a number of frames represented e.g., by a counter value, exceeds a predetermined value. The counter value may be changed, depending on whether the system is in a comfort noise generation state or in a muting period. The frame may be replaced by a frame representing mainly background noise, generated at the transmitting end during speech pauses or at the receiving end, or such a frame and a correctly received frame. The predetermined value may be the length of a muting period or may be the number of lost or corrupted frames preceding a speech frame. A first of the correctly received speech frames that follows a number of lost or corrupted frames may also be replaced. The output frames gradually approach pure speech frames.

Speech decoding method and apparatus for selecting random noise codevectors as excitation signals for an unvoiced speech frame

Abstract: If the same parameter is repeatedly used in an unvoiced frame inherently devoid of pitch, there is produced a pitch of the frame length period, thus producing an extraneous feeling. This can be prevented from occurring by evading repeated use of excitation vectors having the same waveform shape. To this end, when decoding an encoded speech signal obtained on waveform encoding an encoding-unit-based time-axis speech signal obtained on splitting an input speech signal in terms of a pre-set encoding unit on the time axis, input data is checked by CRC by a CRC and bad frame masking circuit 281, which processes a frame corrupted with an error with bad frame masking of repeatedly using parameters of a directly previous frame. If the error-corrupted frame is unvoiced, an unvoiced speech synthesis unit 220 adds the noise to an excitation vector from a noise codebook or randomly selects the excitation vector of the noise codebook.

Device and method for decoding HDTV video

Abstract: HDTV video decoder circuit is disclosed, which has an 1/4 size frame memory for a progressive scanned or interlace scanned video and yet can conduct IDCT and motion compensation to fit to the reduced frame memory size, which, in comparison to a conventional MPEG-2 video decoder which uses a 4×4 IDCT that requires 1/4 frame memory in encoding an interlace scanned image into frame picture only to lose field information of the image resulting in a significant damage to the picture quality, facilitates to maintain the field information as it was resulting in an improvement in the picture quality.

A novel computationally scalable algorithm for motion estimation

Abstract: Because motion estimation represents a major computational load in typical video encoding systems (e.g., around 50% of computation time when full search is used as in [11]), there has been extensive research into fast motion estimation techniques (and thus with the current state-of-art fast algorithms, e.g. [2], the above percentage can be reduced to around 10%). Given the nature of the process, two major classes of complexity reduction techniques have been proposed. These seek to speed up search times by (i) reducing the cost of each matching operation or (ii) reducing the number of points considered in the search region. In fast matching (FM) techniques, a typical approach is to compute the cost function (e.g., SAD) based on a subset of pixels in a block. In fast search (FS) approaches, the complexity reduction comes from restricting the number of points in the search region, based on fixed rules (e.g. three step search) or on initialization based on motion vectors already computed for other blocks or the previous frame. In this paper we use as a baseline algorithm the initialize-refine technique (a modification of the algorithm of [2]) which belongs to the FS class. We concentrate on the case of real time software video encoding, which allows the flexibility of using variable complexity algorithms (VCAs). Thus, we modify our baseline algorithm using a Lagrange multiplier approach similar to that of [1] which allows us to explicitly take into account the trade-offs between search complexity and residual frame energy. Furthermore, we combine this algorithm with a novel fast matching method for SAD estimation which allows us to estimate the SAD based on successive subsets of pixels in a particular block. This method naturally possesses computational scalability because we can stop the computation once we have sufficient confidence in our estimate. This can be easily done in a hypothesis testing framework and gives us one more degree of freedom to control the complexity/residual energy trade-off. We show that the combined algorithm achieves reductions of around 25% in computation time with respect to the original algorithm without SAD estimation. As in [12], these results are further improved by designing a test structure that is optimized for typical sequences and where tests for an early termination of the matching process are only included if they are thought to be worthwhile in terms of the overall complexity.

Scene context dependent reference frame placement for MPEG video coding

Abstract: The MPEG video compression standard effectively exploits spatial, temporal, and coding redundancies in the algorithm In its generic form, however, only a minimal amount of scene adaptation is performed Video can be further compressed by taking advantage of scenes where the temporal statistics allow larger inter-reference frame distances This paper proposes the use of motion analysis (MA) to adapt to scene content The actual picture type (I, P, or B) decision is made by examining the accumulation of motion measurements since the last reference frame was labeled Depending on the video content, this proposed algorithm can achieve from 2% to 139% savings in bits while maintaining similar quality

Method and apparatus for decoding variable rate data

Abstract: A system and method for determining the data rate of a frame of data at a receiver (50) of a variable rate communications system. A vocoder at a transmitter encodes a frame of data at one of the rates of a predetermined set of rates. The data rate is dependent on the speech activity during the time frame of the data. The data frame is also formatted with overhead bits, including bits for error detection and detection. At the receiver (50), the data rate for the frame is determined based on hypothesis testing. Because the data rate is based on speech activity, a hypothesis test may be designed based on the statistics of speech activity. The received data frame is first decoded by a decoder (34) into information bits at the most probable rate as provided by the hypothesis testing module (36). Data check element (42) generates error metrics for the decoded information bits. If the error metrics indicate that the information bits are of good quality, then the information bits are presented to a vocoder (44) at the receiver to be processed for interface with the user. If the error metrics indicate that the information bits have not been properly decoded, then decoder (34) decodes the received data frame at the other rates of the set of rates until the actual data rate is determined.

Video refresh compression

Abstract: A data compression apparatus and method of displaying graphics in a computer system employs a full frame buffer and compressed frame buffer wherein pixel data is sent to a display device and concurrently compressed and captured in parallel so that subsequent unchanged frames are regenerated directly from the compressed frame buffer.

Multi-subframe quantization of spectral parameters

Abstract: Speech is encoded into a frame of bits. A speech signal is digitized into a sequence of digital speech samples that are then divided into a sequence of subframes. A set of model parameters is estimated for each subframe. The model parameters include a set of spectral magnitude parameters that represent spectral information for the subframe. Two or more consecutive subframes from the sequence of subframes may be combined into a frame. The spectral magnitude parameters from both of the subframes within the frame may be jointly quantized. The joint quantization includes forming predicted spectral magnitude parameters from the quantized spectral magnitude parameters from the previous frame, computing the residual parameters as the difference between the spectral magnitude parameters and the predicted spectral magnitude parameters, combining the residual parameters from both of the subframes within the frame, and quantizing the combined residual parameters into a set of encoded spectral bits which are included in the frame of bits.

Method and apparatus for trick play of bitstream data

Abstract: An apparatus for a trick play video player and methods of operating the same result in a video player that provides a compressed data stream of output image data for later playback. The trick play video player comprises a frame creator which receives output image data and creates a reference frame from the output image data. A data stream storage is coupled to the frame creator configured to store the compressed data stream which follows the reference frame. The reference frame and the compressed data stream is decoded to replay the output image data.

Method and apparatus for decoding video signals

Abstract: A method for decoding video signals comprising decoding a bit stream, and reproducing a video signal in reverse order of frames, the bit stream including each frame of the video signal which has been encoded using one of an intra coding system (I picture), a predictive coding system (P picture), and a bidirectionally predictive coding system (B picture), includes a group of frames including at least one frame of I picture, which can be decoded from the I picture and consecutively reproduced in order of the frames, being called a GOP (Group of Pictures); the frames being output in reverse order of the frames to obtain a desired frame, wherein: when the desired frame is one of I picture and P picture, only the I picture and P pictures from the first I picture in a GOP to the desired frame are decoded; and when the desired frame is B picture, only the desired frame is decoded if reference frames required for decoding of the desired frame are present in frame memories. As described above, in the method for decoding video signals according to the present invention, decoding processing of a desired frame is performed each time to output a reproduced image. Consequently, an increase in circuit scale can be avoided, resulting in smooth backward reproduction with a small memory capacity.