A picture signal coding method and decoding method and a picture signal recording medium (10) by which a picture is prevented from being interrupted upon high speed reproduction are disclosed. A GOP is constituted from pictures of 15 frames. Of those pictures, an I-picture and P-pictures are collectively treated as pictures for high speed reproduction and are arranged forwardly of the remaining pictures which are B-pictures. Upon high speed reproduction, only the pictures for high speed reproduction are reproduced.

Picture signal coding method, decoding method and picture signal recording medium

A method is provided for transcoding, i.e., decoding, and re-encoding, a previously encoded video signal, to a second encoded representation. A number k>1 of previously encoded pictures of the previously encoded video signal are received in a buffer. Each of the k previously encoded pictures in the buffer is scanned to gather information on each of the k previously encoded pictures. An encoding parameter is allocated to a first one of the k previously encoded pictures which precedes each other one of the k previously encoded pictures in encoded order of the previously encoded video signal. The encoding parameter is allocated based on the information gathered for each of the k previously encoded pictures. The first previously encoded picture is decoded to produce a decoded picture. The decoded picture is re-encoded to generate a re-encoded picture in a second encoded representation of the video signal. The re-encoding is performed in a fashion which depends on the encoding parameter allocated thereto. An apparatus is also disclosed for carrying out the method including a buffer, a scanner (for performing the scanning and allocating steps), a decoder and an encoder.

Video transcoder with bitstream look ahead for rate control and statistical multiplexing

A system is provided for transmitting data to a plurality of devices. A data source receives data from a video broadcasting source, such as a digital television provides, through a data cable. The data source identifies devices to receive particular sets of data, such as particular programs, from the data cable. The data source identifies particular settings for transmitting to particular devices. The data source adjusts a transmission power to a first device to efficiently provide data reliably to the first device. The data source can assign more or less power for transmitting data to the first device. The data source provides data to the source device using a first data channel. The data source provides data to a second device using a second data channel. The data source receives acknowledgements and control information from the first device and the second device using the second data channel.

System for providing data to multiple devices and method thereof

The present invention provides a transcoder having a MPEG decoder and a MPEG encoder, for changing a GOP structure and the bit rate of an encoded bitstream obtained as a result of an encoding process. The MPEG encoder receives a past encoding parameters generated at a past encoding process as a history information, and performs a present encoding process by using the past encoding parameters selectively so that the present encoding process is optimized. Furthermore, the encoder describe the past encoding parameters into the encoded bitstream as the history information so as to reuse the history information in advance encoding process. The picture quality of the video data does not deteriorate even if decoding and encoding processes are carried out repeatedly by the transcoder.

Transcoding system using encoding history information

Encoding parameters of picture and higher layers of importance to a number of applications, and encoding parameters of slice and lower layers of no importance to all applications are converted into auxiliary packets inserted respectively into a V-blanking area and an H-blanking area of a video-data signal output by a history-information-multiplexing apparatus employed in a video-decoding system. On the other hand, a video-encoding system extracts back the auxiliary packets superposed on the V-blanking area and the H-blanking area from an input base-band video signal. As a result, a technique of superposing information on data can be changed in accordance with the importance of the information and required information can be fetched with ease.

Information processing apparatus, information processing method and recording medium

The coding or decoding of video data with the associated audio and/or other data can be performed, for example, on the basis of the standards ISO/IEC 11172 (MPEG1) or ISO/IEC 13818 (MPEG2). Such coding and decoding can include the conversion of a primary bit stream coded on the basis of such standards into a secondary bit stream with a different data rate. Since the information content of the motion vectors from the primary bit stream retain their validity in the secondary bit stream, it is not necessary to recalculate motion vectors for transcoding. Instead, encoding of the secondary bit stream is performed with the aid of the motion vectors from the primary bit stream which are reused. In such a case, the encoding of the secondary bit stream is carried out in a restricted prediction mode, i.e. only those prediction modes which are described by respective block type or the motion information of the primary bit stream are allowed in the secondary bit stream.

Method and apparatus for transcoding bit streams with video data

Digital storage media like CD, CD-ROM, MOD, DAT, etc. open new fields of application, e.g. for storage and retrieval of moving video information for multimedia services. This paper describes a video codec operating at a bit rate supported by these media, focus being on 1.15 Mbits/s for net video. It is based on the hybrid DPCM/DCT scheme of CCITT Reference Model 8 which had been optimized within CCITT Study Group XV for telecommunications applications at bit rates ranging from 64 kbits/s to 2 Mbits/s. New building blocks have been added to implement trick modes and to improve subjective picture quality. Periodic coding of frames in an intraframe mode provides random access and, thus, fast search and reverse playback features. Adapted coder control, zoom and pan compensation, half pel accuracy of local motion vectors, weighting of transform coefficients, and noise reduction in the coding loop are the main components improving subjective picture quality for the wider range of TV applications.

Adaptation and improvement of CCITT reference model 8 video coding for digital storage media applications

In the process of generating a compatible 4:3 letterbox format television signal, a wide aspect ration 16:9 progressive scan television signal is vertically transcoded from 575 to 431 image lines, converted to line interlaced form and horizontally compressed. A vertically transcoded interlaced luminance component is converted back to progressive scan form via interpolation, and subtracted from a vertically transcoded original progressive scan luminance component to produce a difference (helper) signal. The difference signal is time compressed and multiplexed into upper and lower edge bar regions of the letterbox format. The compatible letterbox signal also is encoded with additional information including vertical high frequency information and horizontal high frequency information separated during the transcoding and compression processes, respectively. The encoding includes modulating the color subcarrier frequency with luminance information, and intraframe averaging. The difference signal and encoded additional information are used by a 16:9 widescreen receiver to produce a 16:9 progressive scan image display with the transcoded number of lines and good resolution.

Auxiliary signal to assist conversion of a letterbox standard aspect ratio television signal to a wide aspect ratio signal

In television transmission systems which use the 'letter-box' technique, an active 16:9 format image is transmitted within a 4:3 image format. This does not, however, overcome the disadvantages of interlaced scanning (e.g. line shake, edge jitter). The invention calls for a progressive 16:9 TV signal with 575 active lines to be generated in the transmitter, transcoded in the vertical direction to 431 lines, converted into an interlace signal, auxiliary information added and the signal transmitted as a compatible TV signal in letter-box format. The auxiliary information comprises signal components with which a progressive signal with vertical resolution approximating to that of the source signal is generated from the interlace signal again and/or higher vertical spectral components which, on transcoding, are separated in the transmitter and/or higher horizontal spectral components which are separated in the transmitter on compressing the format horizontally from 16:9 to 4:3. The appropriate auxiliary information is not, however, generated to obtain a progressive signal with 575 active lines but to obtain the progressive signal transcoded to 431 lines. A 16:9 receiver provides a format-filling progressive-presentation 16:9 image with 431 lines. Splitting the Y-component into three frequency bands and combining the higher-frequency Y-components with the colour components, and the use of an intraframe-average method, enable cross-colour and cross-luminance interference to be avoided and higher-frequency luminance spectral components to be also transmitted.

Tv transmission system

The transcoding system allows a coded bit stream (PBS) conforming to a given norm to be converted to a different data rate, by partial decoding of the video data (VID) to extract the movement information and video data type information. The video data with the second data rate is encoded via the same movement information and video data type information, using movement information prediction and interpolation, the number of prediction modi limited in dependence on video data type. Pref. the incoming and outgoing video data are each based on coded image point blocks, with the movement information and the video data type information associated with each of these blocks, or with macro blocks assembled from a number of blocks.

Dietrich Westerkamp

Papers

Method and apparatus for transcoding bit streams with video data

Adaptation and improvement of CCITT reference model 8 video coding for digital storage media applications

Auxiliary signal to assist conversion of a letterbox standard aspect ratio television signal to a wide aspect ratio signal

Tv transmission system

Method and apparatus for transcoding bitstreams of videodata