摘要:
An MPEG video decoder capable of preventing a buffer for storing a video stream from overflowing and/or underflowing. The video decoding apparatus decodes a coded video bit stream including a series of pictures to produce decoded pictures. The video decoding apparatus includes: a bit buffer for temporarily storing the video bit stream, a decoding circuit for receiving the video bit stream output from the bit buffer and decoding the video bit stream to produce decoded pictures, and a video bit stream control circuit for controlling an amount of the video bit stream to be supplied to the decoding circuit from the bit buffer based on an amount of data of the video bit stream stored in the bit buffer.
摘要:
Discrete cosine transform circuits suitable for inverse discrete cosine transform (IDCT) or forward discrete cosine transform (FDCT) are disclosed. An IDCT circuit includes a group of multipliers and a group of adders/subtracters. The multipliers receive plural pieces of input data which are externally supplied in parallel. Each multiplier has a cosine constant to multiply to the received input data. The adders/subtracters receive multiplication results from the multipliers and perform addition/subtraction thereon to produce output data, which is the result of inverse discrete cosine transform of the input data. An FDCT circuit includes a group of input-stage adders/subtracters, a group of multipliers, and a group of output-stage adders. The input-stage adders/subtracters perform addition/subtraction on input data which are externally supplied in parallel. Computation results of the input-stage adders/subtracters is supplied to the multipliers. The output-stage adders receive multiplication results from the multipliers and produce output data, which is the result of forward discrete cosine transform of the input data. The discrete cosine transform circuits are particularly suitable for use in MPEG video encoders/decoders.
摘要:
A video decoding apparatus for decoding encoded video data to continuously produce decoded pictures. The video data includes a series of pictures, each picture contains a series of slices, and each slice contains a series of macroblocks. A dequantizer performs dequantization of the video data based upon a quantization threshold value. A motion-vector restoring circuit restores data for each macroblock. A direct current error detector is provided to detect erroneous macroblocks based upon the dequantized data. A motion-area error detector is provided to detect erroneous macroblocks based upon the restored motion vector data. An erroneous macroblock is replaced by a corresponding macroblock from a preceding picture. Subsequent macroblocks in a slice may also be replaced by corresponding macroblocks from a preceding picture.
摘要:
In a digital camera, when snapshot shooting is instructed during recording of a moving image, a shot still image is temporarily pushed aside in a memory area for use in pushing aside (7a) in a frame buffer (7). A currently shooting motion image and a still image are displayed in parallel on a display (9), so that a user can confirm a content of a snapshot. The moving image continues to be recorded even during a push-aside operation. After a moving image processing is completed, the still image is processed by an image correcting circuit (4). The frame buffer (7) comprises a plurality of frame recording areas, and is shared on the occasions of a moving image processing and a still image processing. In a normal moving image processing, these areas are utilized in a cyclic manner, and when the still image is shot, any of areas will be utilized. Thereafter, the rest of areas are utilized in the cyclic manner for the moving images. The recording function for the moving image and still image is improved at low cost, it becomes easy to take a snapshot, and the merchandise size is not increased.
摘要:
Structure information on picture within a GOP of a coded data sequence is acquired beforehand. At the time of high-speed reproduction, a high-speed reproduction mode judging unit judges by referring to the picture structure information whether a high-speed smooth reproduction is possible or not. If the high-speed reproduction is possible, a high-speed smooth reproduction control unit performs the high-speed smooth reproduction. If not possible, a high-speed skip reproduction control unit performs high-speed skip reproduction. For reverse reproduction, image data for one GPO, for example, are recoded by an MPEG encoder and then the recoded image data are stored in a storage. Then, a coded data amount predicted from the structure information on the picture within the GOP is compared with the capacity of the storage, and a countermeasure such as raising a compression ratio is taken if the estimated coded data amount exceeds the capacity of the storage.
摘要:
An encoding apparatus 100 performs intra-frame encoding or inter-frame encoding using a predetermined scheme, or performs an orthogonal transform on an image as one process in the intra-frame encoding or the inter-frame encoding. In order to perform the intra-frame encoding, the inter-frame encoding, or the orthogonal transform, various parameters to be specified by the encoding apparatus are specified as an abbreviated parameter which uses a number of bits less than the number of bits that is assigned by the specification. This enables to reduce the data amount of a parameter in the coded data.
摘要:
In a digital camera, when snapshot shooting is instructed during recording of a moving image, a shot still image is temporarily pushed aside in a memory area for use in pushing aside (7a) in a frame buffer (7). A currently shooting motion image and a still image are displayed in parallel on a display (9), so that a user can confirm a content of a snapshot. The moving image continues to be recorded even during a push-aside operation. After a moving image processing is completed, the still image is processed by an image correcting circuit (4). The frame buffer (7) comprises a plurality of frame recording areas, and is shared on the occasions of a moving image processing and a still image processing. In a normal moving image processing, these areas are utilized in a cyclic manner, and when the still image is shot, any of areas will be utilized. Thereafter, the rest of areas are utilized in the cyclic manner for the moving images. The recording function for the moving image and still image is improved at low cost, it becomes easy to take a snapshot, and the merchandise size is not increased.
摘要:
A monitoring unit monitors continuously wavelet transform component output from a wavelet transformer. When a condition “make all the components of the HH sub-band 0” is applied as a quantization strategy, the monitoring unit detects the maximum value N among the components in the HH sub-band and determines the threshold as N+1. The threshold is then sent to a quantizer.
摘要:
A region setting unit 64 sets multiple global regions in a frame image. A bit number adjustment unit 62 adjusts the number of bits of the local motion vectors LMV which are to be obtained for each global region. A local motion vector detection unit 66 detects the local motion vectors LMV with the number of bits adjusted by the bit number adjustment unit 62 in units of macro blocks for each global region. A global motion vector calculation unit 68 calculates the global motion vector GMV which represents the global motion for each global region. A local motion vector difference coding unit 72 calculates the difference ΔLMV, which is the difference between each local motion vector LMV and the global motion vector GMV, for each global region, and performs coding thereof.
摘要:
An image coding apparatus is provided which satisfies various levels of demands on image distribution, both from image providers and from users. The image coding apparatus includes a coding block which codes predetermined image data. A separation unit separates the coded image data into basic data for reproducing contents of the coded image data as a visible image, and complementary data for complementing the basic data, so that the two pieces of data are distributed on different occasions. An adding unit adds information for independent copyright control to at least either one of the basic data and the complementary data.