Abstract: A cross-layer optimization method for controlling a bit rate of a video coder/decoder (codec) in video data transmission for wireless devices such as a wireless broadband (WiBro) system terminal that adapts to changing transmission/reception characteristics and usage. The method typically includes checking, by a sender, radio channel state information of a sender side and a receiver side; determining, by the sender, a transmission bit rate of a video codec by using the radio channel state information of the sender side; and adjusting, by the sender, the transmission bit rate of the video codec by using the radio channel state information of the receiver side when a communication network used by a receiver typically based on the type of a communication network being used by the sender.

Abstract: A moving picture coding method includes: determining a luminance change by determining whether it is possible that a luminance change equal to or greater than a predetermined amount has occurred between the reference coded picture and a current picture; determining a flat region by determining whether a degree of non-uniformity in pixel values in a current block is smaller than a predetermined threshold; and determining a quantization width wherein, when it has been determined that it is possible that the luminance change equal to or greater than the predetermined amount has occurred and that the degree of non-uniformity is smaller than the predetermined threshold, a quantization width is determined to be smaller than a quantization width when it has not been determined to be possible that the luminance change equal to or greater than the predetermined amount has occurred or that the non-uniformity degree is smaller than the predetermined threshold.

Abstract: Video encoding (such as H.263, MPEG-4, H.264/AVC) modifies TMN5-type rate control frame skipping and quantization parameter updating according to buffer fullness levels with I-frame initial quantization parameter values depend upon quantization parameter value of prior P-frames but also has within I-frame prediction and parameter increase to avoid excessive bits. And variable input frame rate is accommodated by adjusting buffer fullness measures. The quantization also applies to image compression.

Abstract: Provided is a method and apparatus for controlling a bit-rates in which an amount of generated bits is adjusted according to the complexity of each frame, and a bit-rate within a frame can be further effectively adjusted by applying different quantization parameter (QP) values to respective macro blocks. In the apparatus for controlling a bit-rate, a motion compensated temporal filtering (MCTP) operation is performed for each group of pictures (GOP) in an input scalable layer, and thereafter bits are allocated to respective frames in consideration of frame type and frame complexity. Furthermore, a QP is adaptively determined in the unit of a macro block on the basis of the allocated bits.

Abstract: In an internet protocol television (IPTV) system, fast channel change (FCC) transactions that experience late multicast joins are handled specially, thereby allowing the system to be provisioned for the vast majority of multicast joins that are within an expected range. During an FCC transaction, the subscriber interface device, such as a set-top box (STB), can determine how long it can wait to join the multicast stream of the new channel before a gap can be predicted to occur in the handover from the FCC unicast to the multicast. If the STB has not joined the multicast stream by the determined time, a recovery procedure is invoked in which the STB sends a RESTART request to the FCC server which, in turn, increases the rate of the FCC unicast as if the FCC transaction were restarted, thus allowing the handover to occur seamlessly. This solution reduces the demands of each FCC transaction, allowing for greater scalability and reduced cost.

Abstract: Activities of a video signal are obtained for subblocks of each macroblock of each picture. The smallest activity is detected as an input-picture activity per macroblock. Obtained are activities of a motion-compensated predictive signal per first picture and activites of the video signal per second picture, for the subblocks of each macroblock. A mean value of the activities is obtained per macroblock for each picture, as an error activity per macroblock. A mean error activity is obtained for error activities per picture. A quantization step size for quantization of the video signal is adjusted per macroblock, according to the input-picture activity, to obtain a smaller step size when the error activity is equal to or larger than the mean error activity than when the former is smaller than the latter.

Abstract: A run-level domain transcoder receives a stream of compressed frames carried in a bit stream. The run-level domain transcoder decodes the bit stream into run-level pairs and selectively processes the compressed frames so as to, among other things, reduce the number of bits necessary to represent the compressed frames.

Abstract: An image coding apparatus which reduces buffer capacity to a minimum and includes an image coding processing unit which generates intermediate data by executing a part of a process in the coding on the image data; a packetizing unit which generates an image stream by executing a process other than the part of the process in the coding on the intermediate data, such as for example arithmetic coding, and packetizes the generated image stream in synchronization with the image stream generation process.

Abstract: A quantizer and dequantizer for use in a video coding system that applies non linear, piece-wise linear scaling functions to video information signals based on a value of a variable quantization parameter. The quantizer and dequantizer apply different non linear, piece-wise linear scaling functions to a DC luminance signal, a DC chrominance signal and an AC chrominance signal. A code for reporting updates of the value of the quantization parameter is interpreted to require larger changes when the quantization parameter initially is large and smaller changes when the quantization parameter initially is small.

Abstract: An adaptive transversal filter having tap weights Wj which are products of corresponding tap coefficients Cj and tap gains Mj is provided. A filter control loop controls all of the tap coefficients Cj such that an error signal derived from the filter output is minimized. One or more tap control loops controls a tap gain Mk such that the corresponding tap coefficient Ck satisfies a predetermined control condition. For example, |Ck| can be maximized subject to a constraint |Ck|?Cmax, where Cmax is a predetermined maximum coefficient value. In this manner, the effect of quantization noise on the coefficients Cj can be reduced. Multiple tap control loops can be employed, one for each tap. Alternatively, a single tap control loop can be used to control multiple taps by time interleaving.

Abstract: A system that compresses a digital image. During operation, the system obtains a digital image in which the image components are de-correlated into separate channels containing luminance information and chrominance information. Next, the system receives a quality number for the luminance channel and a quality number for the chrominance channels, and uses the quality numbers to determine a target bitrate for the luminance channel and for the chrominance channels, respectively. Given the target bitrate for the luminance channel and the target bit rate for the chrominance channels, the system performs rate distortion optimizations separately on the luminance and chrominance channels to determine which portions of the luminance bitstream and which portions of the chrominance bitstream are to be included in the final bitstream. The system then uses the stored rate-distortion information to generate a preview of the digital image without performing entropy coding each time the quality settings are changed.

Abstract: The quantization parameter QP is well-known in digital video compression as an indication of picture quality. Digital symbols representing a moving image are quantized with a quantizing step that is a function QSN of the quantization parameter QP, which function QSN has been normalized to the most significant bit of the bit depth of the digital symbols. As a result, the effect of a given QP is essentially independent of bit depth—a particular QP value has a standard effect on image quality, regardless of bit depth. The invention is useful, for example, in encoding and decoding at different bit depths, to generate compatible, bitstreams having different bit depths, and to allow different bit depths for different components of a video signal by compressing each with the same fidelity (i.e., the same QP).

Abstract: A video encoding method and system are provided for encoding a video sequence. The video sequence includes N sub-sequences which each includes a plurality of frames. When the video encoding system encodes the jth frame in the ith sub-sequence of the video sequence, the frames previous to the jth frame in the ith sub-sequence have been encoded. Based on the encoded frames, an initial quantization scale is generated. According to the initial quantization scale, the jth frame of the ith sub-sequence is encoded in the inter-encoded mode. Whether the jth frame in the ith sub-sequence is a “scene change” relative to the (j?1)th frame in the ith subsequence is judged, and if YES, based on the initial quantization scale, an adjusted quantization scale is generated. Moreover, the jth frame in the ith sub-sequence is re-encoded in accordance with the adjusted quantization scale.

Abstract: The picture coding method according to the present invention is a picture coding method for coding a picture on a block-by-block basis through orthogonal transformation and quantization, and coding a quantization matrix that is used to derive quantization steps for frequencies of orthogonal transformation coefficients, the method comprising: calculating a difference value between each of frequency components included in the quantization matrix and a predetermined value corresponding to said each of the frequency components; and coding the difference value into a variable length code, wherein a code length of the variable length code is shorter as the difference value is smaller, or equal to a code length of a neighboring difference value of said difference value.

Abstract: A decoding apparatus includes a decoder configured to receive a series of encoded pictures and to decode each of the encoded pictures to produce a series of decoded pictures, each of the encoded pictures being either intra-encoded or inter-encoded, and each of the decoded pictures being either referred or, non-referred, a blocking noise suppressor configured to suppress blocking noise of each of the decoded pictures, and a controller configured to detect an amount of a load, to run each of the referred decoded pictures through the blocking noise suppressor if the detected amount of the load is no lower than a given threshold, and to have each of the non-referred decoded pictures bypass the blocking noise suppressor if the detected amount of the load is no lower than the threshold.

Abstract: The picture coding method according to the present invention is a picture coding method for coding a picture on a block-by-block basis through orthogonal transformation and quantization, and coding a quantization matrix that is used to derive quantization steps for frequencies of orthogonal transformation coefficients, the method comprising: calculating a difference value between each of frequency components included in the quantization matrix and a predetermined value corresponding to said each of the frequency components; and coding the difference value into a variable length code, wherein a code length of the variable length code is shorter as the difference value is smaller, or equal to a code length of a neighboring difference value of said difference value.

Abstract: This disclosure describes adaptive filtering techniques to improve the quality of captured imagery, such as video or still images. In particular, this disclosure describes adaptive filtering techniques that filter each pixel as a function of a set of surrounding pixels. An adaptive image filter may compare image information associated with a pixel of interest to image information associated with a set of surrounding pixels by, for example, computing differences between the image information associated with the pixel of interest and each of the surrounding pixels of the set. The computed differences can be used in a variety of ways to filter image information of the pixel of interest. In some embodiments, for example, the adaptive image filter may include both a low pass component and high pass component that adjust as a function of the computed differences.

Abstract: A video data compression apparatus with which compressed video data of suitable amounts of data can be produced and the time required for processing is short. The apparatus approximates a real difficulty data Dj indicating the difficulty of the pattern of each picture by the ME residual, flatness, and intra AC and further calculates the target amount of data Tj of the compressed video data from the approximated real difficulty data Dj. An encoder performs compression and coding so that the amount of data of the compressed video data becomes substantially the target amount of data Tj.

Abstract: Presented herein are optimized single inverse quantization engines for a plurality of standards. In one embodiment, there is presented a system for inverse quantizing quantized frequency coefficients. The system comprises an inverse quantizer for inverse quantizing video data encoded in accordance with a first encoding standard and for inverse quantizing video data encoded in accordance with a second encoding standard. In another embodiment, there is presented a decoder for decoding video data. The decoder comprises an inverse quantizer operable to inverse quantize video data encoded in accordance with a first encoding standard and for inverse quantizing video data encoded in accordance with a second encoding standard.

Abstract: A measure of quality of compressed video signals is obtained without reference to the original uncompressed version, but generated directly from the coded image parameters, thereby avoiding the need to decode the compressed signal. A first measure is generated from the quantizer step size and a second measure is generated as a function of the number of blocks in the picture that have only one transform coefficient. The two measures are combined. Adjustments may be made to the step-size based measure to compensate for spatial or temporal masking effects.

Abstract: A quantization matrix used in inverse quantization is generated. A received bitstream includes a coded truncated quantization matrix. The coded truncated quantization matrix has first coded bits and second coded bits. The first coded bits include bits obtained by coding a transmitting part of quantization elements and the second coded bits includes bits obtained by coding an end code. The coded truncated quantization matrix is decoded until the second coded bits corresponding to the end code are read out, to obtain the transmitting part of quantization elements. At least one additional quantization element is obtained. A complete quantization matrix is generated, using the transmitting part of quantization elements and at least one additional quantization element, by ordering the transmitting part of quantization elements and at least one additional quantization element in a zig-zag scan.

Abstract: A method of estimating a quantization parameter is provided. The method is applied to a de-blocking filter. The de-blocking filter de-blocks a decoded block-based image according to the quantization parameter, and the block-based image is coded and decoded in units of macroblocks. The method comprises calculating blocking degrees of a number of block edges corresponding to the macroblocks; and estimating the quantization parameter according to a sum of the blocking degrees.

Abstract: A method for object edge detection in a macroblock and a method for deciding quantization scaling factor are disclosed. This method calculates and compares the pixel means and means of absolutely difference of a plurality of pixel blocks in a macroblock to achieve the purpose of detecting if there is an object edge or flat area in a macroblock. In the meantime, the image structure of macroblock is analyzed and classified and its related messages are used for bit rate control, such that the visual effect of the compressed image can be appropriately enhanced.

Abstract: Some embodiments limit the changes to a buffer occupancy accumulator with respect to a target number of bits of the current frame. Limiting the change of the buffer occupancy accumulator will prevent one odd significantly different frame from significantly changing the quantization. Some embodiments improve upon the quantizer adjustment by making more accurate estimates of the amount of information needed to encode each macroblock. Specifically, some embodiments estimate the bits per macroblock in a manner that varies from frame type to frame type. Specifically, for frame types with motion compensation, some embodiments exploit the correlation between the complexity of the macroblock and the number of bits needed. In the case of frame types without motion compensation, some embodiments impose a model that biases bit allocation towards smaller activity macro blocks.

Abstract: A data processing apparatus able to generate encoded data able to give a high quality decoded image, wherein a Q-calculation circuit specifies a bit rate by which the encoded data is decoded at the time of decoding based on encoded data, then the Q-calculation circuit controls quantization scales of a quantization circuit based on the specified bit rate.

Abstract: The invention concerns a method (200) and system (100) performing a trick mode on a video signal containing a plurality of original pictures. The method includes the steps of selectively skipping (214) at least one of the original pictures to convert the video signal to a trick mode video signal in response to a trick mode command and selectively inserting (224) at least one dummy bidirectional predictive picture in the trick mode video signal using field-based prediction. The method can also include the steps of monitoring (220) the trick mode video signal in which the step of selectively inserting at least one dummy bidirectional predictive picture in the trick mode video signal can be done if the bit rate of the trick mode video signal exceeds a predetermined threshold.

Abstract: Disclosed herein in one embodiment is an adaptive coding threshold algorithm for a videoconference system which alleviates problems due to the erroneous recoding of stationary areas of images caused by image noise. The algorithm, which is preferably implementable on a videoconference encoder, assesses the coding parameters for a current macroblock and the coding parameters for that same macroblock the last time it was coded. If for both macroblocks the coding was non-intra, with a [0,0] motion vector, and with a low quantization parameter, a determination is made that the current macroblock depicts a stationary image. Accordingly, the algorithm increases the coding threshold (T1) for the blocks within that macroblock, so that it becomes more difficult for those particular blocks to be recoded. This renders the block with stationary content less susceptible to erroneous recoding, while preserving system bandwidth and improving image quality.

Abstract: Method For Implementing A Quantizer In A Multimedia Compression And Encoding System is disclosed. In the Quantizer system of the present invention, several new quantization ideas are disclosed. In one embodiment, adjacent macroblocks are grouped together into macroblock groups. The macroblock groups are then assigned a common quantizer value. The common quantizer value may be selected based upon how the macroblocks are encoded, the type of macroblocks within the macroblock group (intra-blocks or inter-blocks), the history of the motion vectors associated with the macroblocks in the macroblock group, the residuals of the macroblocks in the macroblock group, and the energy of the macroblocks in the macroblock group. The quantizer value may be adjusted in a manner that is dependent on the current quantizer value. Specifically, if the quantizer value is at the low end of the quantizer scale, then only small adjustments are made.

Abstract: A quantizer and dequantizer for use in a video coding system that applies non linear, piece-wise linear scaling functions to video information signals based on a value of a variable quantization parameter. The quantizer and dequantizer apply different non linear, piece-wise linear scaling functions to a DC luminance signal, a DC chrominance signal and an AC chrominance signal. A code for reporting updates of the value of the quantization parameter is interpreted to require larger changes when the quantization parameter initially is large and smaller changes when the quantization parameter initially is small.

Abstract: A transcoder calculates a reference conversion factor on the basis of a ratio between a total target bit rate of a whole second stream and an total input bit rate of a whole first stream and calculates a coefficient of variation from the total target bit rate of the whole second stream and an average output bit rate of a converted second stream in the N period. Next, a quantization step conversion factor in the next (N+1) period is calculated by adding the coefficient of variation to the reference conversion factor. Then, a quantization step value of a second stream in the (N+1) period is calculated by multiplying a quantization step value of a first stream in the (N+1) period by the quantization step conversion factor.

Abstract: A Poisson-quantization noise model for modeling noise in low-light conditions is described. In one aspect, image information is received. A Poisson-quantization noise model is then generated from a Poisson noise model and a quantization noise model. Poisson-quantization noise is then estimated in the image information using the Poisson-quantization noise model.

Abstract: The image encoding device of the present invention is an image encoding device that encodes a still image and a moving image, the device including: a determination unit that determines a first upper limit and a second upper limit, the first upper limit indicating an upper limit of the amount of code per picture of still images, and the second upper limit indicating an upper limit of the amount of code per picture in a moving image; an encoding unit that encodes each of the still images and the moving image in such a manner that the first and second upper limits are satisfied; a multiplexing unit that generates a stream by multiplexing the encoded still images and the encoded moving image; a generation unit that generates management information that identifies the first and second upper limits; and an output unit that outputs the stream and the management information.

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 relates generally to systems, methods, and computer program products for optimally allocating a fixed number of bits among a plurality of multi-media data channels. The optimal number of bits is determined by preprocessing each channel to calculate complexity data, and then the complexity data is used to determine the optimal number of bits to assign to each channel. The optimal number of bits may be determined by a closed loop controller in communication with one or more channel encoders, and the multi-media channels may contain video data conforming to the MPEG2 video format.

Abstract: A video encoder is disclosed that includes an encoder circuit, a quantizer circuit and a control circuit. The encoder circuit may be configured to generate a number of coefficient values in response to a video stream and a number of quantized values. The quantizer circuit may be configured to generate the number of quantized values in response to the coefficient values, two or more quantization dead zones and two or more offsets. The control circuit may be configured to set the two or more quantization dead zones and the two or more offsets to different values. The two or more quantization dead zones and the two or more offsets are independently programmable.

Abstract: A digital video coding system is provided that is capable of reducing the load of a CPU (Central Processing Unit) that controls a video coding system for implementing a digital video data compression/decompression standard such as MPEG-1, 2, 4, H.261 or H.263. In a conventional video coding system, the circuit configuration and control method of a variable length encoder are becoming increasingly complex with the development of a video compression/decompression standard. In a conventional system structure, a complex control operation must be carried out, such that there is a problem in that the load of the CPU controlling the video coding system increases. Thus, the video coding technology is provided to reduce the load of the CPU necessary for controlling a VLC (Variable Length Coding) unit.

Abstract: An inputted digital signal of a first format (DV video signal) is restored to a variable-length code by having its framing cancelled by a de-framing section 11, then decoded by a variable-length decoding (VLD) section 12, inversely quantized by an inverse quantizing (IQ) section 13, and inversely weighted by an inverse weighting (IW) section 14. Then, required resolution conversion in the orthogonal transform domain (frequency domain) is carried out on the inversely weighted video signal by a resolution converting section 16. After that, the video signal having the resolution converted is weighted by a weighting (W) section 18, then quantized by a quantizing (Q) section 19, coded by variable-length coding by a variable-length coding (VLC) section 20, and outputted as a digital signal of a second format (MPEG video signal).

Abstract: A video encoder includes a programmable rate controller. In one embodiment, the programmable rate controller includes a variable bit rate controller, a constant bit rate controller, and an arbitration logic for selecting one of the two outputs. An embodiment of a variable bit rate controller tracks long-term changes to average bit rate. An embodiment of a constant bit rate controller classifies macroblock types, determines a statistical indicator of complexity for each macroblock type, and generates a target bit rate based on estimated complexity.

Abstract: An adaptive transversal filter having tap weights Wj which are products of corresponding tap coefficients Cj and tap gains Mj is provided. A filter control loop controls all of the tap coefficients Cj such that an error signal derived from the filter output is minimized. One or more tap control loops controls a tap gain Mk such that the corresponding tap coefficient Ck satisfies a predetermined control condition. For example, |Ck| can be maximized subject to a constraint |Ck|?Cmax, where Cmax is a predetermined maximum coefficient value. In this manner, the effect of quantization noise on the coefficients Cj can be reduced. Multiple tap control loops can be employed, one for each tap. Alternatively, a single tap control loop can be used to control multiple taps by time interleaving.

Abstract: An apparatus for partitioning moving picture data comprises a first quantizing unit for first-quantizing a received video signal and outputting a first-quantized signal; and a second quantizing unit for second-quantizing the first-quantized signal and partitioning the first-quantized signal into a preceding part and a succeeding part.

Abstract: An encoding apparatus includes a pre-encoding unit that performs learning based on input image data from before starting a video recording; and an encoding unit that encodes image data using an encoding parameter. The pre-encoding unit includes an image input unit; a motion searching unit that obtains a motion vector of an image based on current image data and past image data; and a table group that represents a relation between encoding parameters and an amount of information generated for various scenes. The pre-encoding unit selects a first table close to a combination of brightness, hue, and complexity of a pattern of a current image and the motion vector, from the table group, and takes the first table as the result of the learning.

Abstract: A rate control system is disclosed for video coding applications. The rate controller assigns a quantization parameter for video data in a picture in response to complexity indicators indicative of spatial complexity, motion complexity and/or bits per pel of the picture. A virtual buffer based quantizer parameter is proposed based on a virtual buffer fullness analysis and a target rate estimate, which is derived from the complexity indicators. A second quantizer parameter is proposed from a linear regression analysis of quantizer parameters used to code previously coded pictures of similar type (e.g., I pictures, P pictures or B pictures). A coding policy decision unit defines a final quantizer parameter from a comparison of the two proposed quantizer parameters.

Abstract: A method and system are provided for encoding a picture. The method includes encoding the picture into a first encoded picture using a first universal quantizer. If a size of the first encoded picture is greater than a maximum picture size, the method includes encoding the picture into a second encoded picture using small quantizers for smooth regions of the picture and large quantizers for complex regions. If a size of the second encoded picture is still greater than a maximum picture size, the method includes encoding the picture into a third encoded picture with revised quantizers for complex regions and dropping high frequency coefficients if necessary to ensure the encoded picture size never exceeds the maximum size.

Abstract: The present invention provides a quantization control system for video coding, for optimizing bit allocation based on visual priority which expresses at high precision human visual characteristics for videos, thereby improving subjective image quality of the whole image even with a limited number of bits. An object is extracted from a picture of an input image (S1) and a gaze parameter V(j) for the extracted object is calculated (S2). Then, a texture attribute parameter t(k) of each macroblock included in the object is calculated (S3). The gaze parameter V(j) and texture attribute parameter t(k) are used to calculate a visual priority parameter w(k) for each macroblock. Based on this parameter w(k), a quantization parameter is determined.

Abstract: A rate controller for allocating a bit budget for video frames to be encoded is disclosed. The rate controller of the present invention considers many different factors when determining the frame bit budget including: desired video quality, target bit rate, frame type (intra-frame or inter-frame), frame duration, intra-frame frequency, frame complexity, intra-block frequency within an intra-frame, buffer overflow, buffer underflow, and the encoded video frame quality for a possible second pass.

Abstract: A rate controlling method for computing a reference quantization parameter is provided, for use in a transcoder having a variable length decoder, an inverse quantizer, a quantizer and a variable length encoder. The rate controlling method comprising: receiving an input quantization parameter and motion information for each of the macroblocks from the variable length decoder; analyzing the similarity of motion information between a current macroblock and its neighboring macroblocks to compute a scaling factor for the current macroblock when allocated within P- and B-pictures; computing a bit difference between a target outputting bit stream and a real outputting bit stream; estimating the fullness of a virtual buffer to encode the current macroblock in view of the scaling factor; and computing the reference parameter based on a target bit rate, the first quantization parameter and the bit difference.

Abstract: A method transcodes a compressed multi-layer video bitstream that includes a base layer bitstream and an enhancement layer bitstream. The base and enhancement layers are first partially decoded, and then the partially decoded signals are combined with a motion compensated signal yielding a combined signal. The combined signal is quantized into an output signal according to a quantization parameter, and the output signal is variable length encoded as a single layer bitstream. In a preprocessing step, the enhancement layer can be truncated according to rate control constraint, and the same constraints can also be used during the quantization.

Abstract: A process and apparatus for displaying and recording image data can be smoothly performed in characteristic methods by computing a quantization parameter for use in compression of image data, obtaining a difference in the amount of processes between the display of image data and the recording of image data, and managing memory of temporarily stored image data for regeneration of recorded image data.

Abstract: A data encoding apparatus operable to encode a plurality of data blocks produces encoded data in accordance with at least one of a selectable target data quantity or a selectable target data quality.

Abstract: This invention employs a scheme to allow an input video signal to undergo encoding, e.g., predictive encoding, DCT processing, quantization at fixed quantization step size and variable length encoding to generate first encoded data to determine (calculate) allocated code quantity every frame or every GOP on the basis of data quantity every predetermined time, e.g., every frame or every GOP of the first encoded data and total quantity of usable data to encode the input video signal every predetermined time on the basis of the allocated code quantity to generate second encoded data. Thus, variable rate encoding such that encoding rate changes every predetermined time is realized. As a result, even if pictures (frames) of complicated are successive, there is no possibility that quantization step size is caused to be large with respect to these pictures as in the conventional apparatus. Thus, uniform high picture quality can be obtained through the entirety.