CA2206454A1 - Method and apparatus for coding digital video signals - Google Patents
Method and apparatus for coding digital video signalsInfo
- Publication number
- CA2206454A1 CA2206454A1 CA002206454A CA2206454A CA2206454A1 CA 2206454 A1 CA2206454 A1 CA 2206454A1 CA 002206454 A CA002206454 A CA 002206454A CA 2206454 A CA2206454 A CA 2206454A CA 2206454 A1 CA2206454 A1 CA 2206454A1
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- Prior art keywords
- picture
- coding
- pictures
- detector
- intraframe
- Prior art date
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- Abandoned
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/85—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using pre-processing or post-processing specially adapted for video compression
- H04N19/87—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using pre-processing or post-processing specially adapted for video compression involving scene cut or scene change detection in combination with video compression
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
- H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
- H04N19/103—Selection of coding mode or of prediction mode
- H04N19/107—Selection of coding mode or of prediction mode between spatial and temporal predictive coding, e.g. picture refresh
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
- H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
- H04N19/136—Incoming video signal characteristics or properties
- H04N19/137—Motion inside a coding unit, e.g. average field, frame or block difference
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
- H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
- H04N19/17—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object
- H04N19/172—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object the region being a picture, frame or field
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/60—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding
- H04N19/61—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding in combination with predictive coding
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Compression Or Coding Systems Of Tv Signals (AREA)
Abstract
For future digital television broadcasting and the interactive communications services associated therewith, video data must be greatly reduced in terms of their volume of data by means of suitable coding devices. One coding method provided for this is the MPEG2 standard. If, during the coding, a change in the picture scene occurs within successive Groups of Pictures, no rational basis for the prediction of the B
and P frames exists for the current Group of Pictures.
As a result, the reconstruction result in the decoder will remain unsatisfactory. According to the invention, such scene changes are detected and the first picture of the new scene is intraframe-coded.
and P frames exists for the current Group of Pictures.
As a result, the reconstruction result in the decoder will remain unsatisfactory. According to the invention, such scene changes are detected and the first picture of the new scene is intraframe-coded.
Description
CA 022064~4 1997-0~-29 PD960037 D94/156A-Ha-300197 Method and apparatus for coding digital video signals The invention relates to a method and an apparatus for coding digital video signals.
Prior art For future digital television broadcasting (DVB = Digital Video Broadcasting) and the interactive communications services associated therewith, vldeo data must be substantially reduced in terms of tr.e volume of data by means of suitable coding devices.
This step is necessary in order to be able to transmit more programmes via existing channels or to communicate moving picture sequences in already existing narrow-band transmission paths. One coding method provided for this purpose is the MPEG2 standard (ISO/IEC 13818).
Invention In order to obtain the highest possible compression factor during coding, the input pictures are combined in Groups of Pictures (GOP) in the case of MPEG. The individual pictures are coded differently within such a Group of Pictures. According to MPEG, a Group always consists of one intraframe-coded frame (I frame) as well as normally a plurality of P frames (predicted frame) and/or B ~rames (bidlrectlona y calculated frames), it being true here as well as in the following text that "frame" may also be replaced by "field".
The data rate necessary for transmitting a frame from this Group depends on the relevant frame type (I, P or B) as well as the current picture contents. The largest relative volume of data within a Group of Pictures is allotted to the I frames. They contain all the data required for complete reconstruction in the decoder. In contrast, P frames are predicted from I frames or a preceding P frame, that is to say the presence of a complete I frame in the relevant Group of Pictures is CA 022064~4 1997-0~-29 PD960037 D94/156A-Ha-300197 necessary for the reconstruction of the P frames at the receiving end. For this purpose, it is then necessary to code only the difference from the preceding I or P
frame. B frames, on the other hand, are essentially calculated (interpolated) from already reconstructed I
or P frames. The volume of data which must be transmitted for a B frame is correspondingly low.
Certain picture types may also contain individual macroblocs of other picture types, for example macroblocs may occur in P and B pictures at picture excerpts which could otherwise be coded only with insufficient efficiency.
Although the above-described classification of the frames into different frame types permits a very high coding efficiency, it imparts to the different frame types different degrees of sensitivity to transmission errors. Thus, transmission or reconstruction errors within B frames remain restricted to the corresponding B frame, whereas erroneous I and P frames can affect the entire Group of Pictures (GOP). In the case of the most frequently chosen MPEG2 parameter of 12 frames per GOP, the time duration for this may last up to approximately half a second (at 50 Hz frame frequency, at 60 or 59.94 Hz frame frequency correspondingly shorter) and is thus very disturbing to a viewer.
A similar effect regarding error degradation may also occur when, during the coding of a feature film, a change in the picture scene occurs within a Group of Pictures. In this case, no rational basis for the prediction of the B and P frames exists for the current Group of Pictures, rather the first picture of the new scene is largely coded with intraframe macroblocs, on account of the internal control of the coder. Since the allocated volume of data for a P frame is not large enough to intraframe-code large portions of the picture with good quality, the reconstruction result in the decoder will remain unsatisfactory. Only in the following Group of Pictures do stable conditions - CA 022064~4 1997-0~-29 PD960037 D94/156A-Ha-300197 .
exist once again for the coding process, which permit satisfactory reconstruction.
Previous coding processes for data reduction are ~ei on feeding the volume of data !picture sequerlces;, which originates from a film scanner, for example, tC' an MPEG coder which continuously generates a data-reduced bit stream. In this concept, scene cuts of the original film coincide completely arbitrarily with a frame type determined by the coder, which may lead to the above-described error degradation within a Group of Pictures.
The invention is based on the object of specifying a method in which the coding process ls synchronized with a scene change that is present. This object is achieved by means of the method specified in Claim 1.
The invention is based on the further object of specifying an apparatus for application of the method according to the invention. This bject lS achievel r, ,, means of the apparatus specified ir. Claim 6.
For this purpose, a scene detector is connected between the picture generator (film scanner, camera, recording device or another signal source) and the coder. The said scene detector generates a suitable control signal and causes the coding process, in the event of a scene change, to begin with a new Group of Pictures, that is to say with an I-coded picture. This advantageously prevents a scene change from falling in the middle of a Group of Pictures, for example, and thus reconstruction with impaired quality from being engendered at the decoder. This measure advantageously requires no additional outlay in the decoder and consequently does not lead to an increase in the complexity and hence the costs in the end unit, that is to say a decoder in a set-top box or in a televlsion set/video recorder/DVD player (Digital VideoDisk).
In principle, the method according to the invention consists in the fact that, for coding digital CA 022064~4 1997-0~-29 PD960037 D94/156A-Ha-300197 video signals, in which, in each case with a defined sequence, an intraframe-coded picture and at least one other picture coding type for a further picture or further pictures are used in a group of successive pictures, pixel values which change greatly from one picture to another picture or greatly changing picture contents are determined in a detector and the further coding is controlled in such a way that intraframe coding is carried out for a picture having greatly changing pixel values or greatly changing picture contents, independently of the position of this picture within the group.
Advantageous developments of the method according to the invention emerge from the associated dependent claims.
In principle, the inventive apparatus for coding digital video signals, in which, in each case with a defined sequence, an intraframe-coded picture (I) and at least one other picture coding type (P, B) for a further picture or further pictures are used in a group of successive pictures, is provided with:
- a detector, which determines pixel values whlch change greatly from one picture to another picture or greatly changing picture contents;
- a coder, which is controlled by the detector in such a way that intraframe coding is carried out for a picture having greatly changing pixel values or greatly changing picture contents, independently of the position of this picture within the group.
Advantageous developments of the apparatus according to the invention emerge from the associated dependent claim.
Drawing An exemplary embodiment of the invention is described with reference to the drawing, in which:
Figure 1 shows an example of a scene-controlled MPEG
coder.
CA 022064~4 1997-0~-29 PD960037 D94/156A-Ha-300197 Exemplary embodiments The video signal is drawn from a picture generator 1, which may be a film scanner, a television camera or any desired analog picture source (for example tape recording device). This signal is first of all fed to an analog/digital converter 2 in order that digital input data can be made available for the coder.
If the signal generator which is available is already a digital signal source, the latter can be connected to the circuit arrangement via input 3. The signal at input 3 is then fed to a scene detector lu, wrlic.~.
comprises, for example, a frame memory 4, a subtractlon stage 5 and a threshold value decision circuit 6. The current frame n of the signal source is available at the input of the frame memory 4 and the preceding frame n-1 delayed by one frame period is available at the output. The sum of the absolute value differences between the pixels of the two frames, for example, is calculated by means of the subtraction stage 5. This summation value is then fed to the threshold value decision circuit 6. Depending on this summation value, the threshold value decision circuit generates a control signal for the MPEG coder 8. The characteristic of the threshold value decision circuit is in this case dimensioned in such a way that differences in the same picture scene which are caused, for example, by moving objects or by slow camera panning trigger no cGntrol signal or a first control signal (in the case of a relatively small summation value), but that a scene change which is characterized by completely different picture information leads to an unambiguous control signal or a second control signal (in the case of a relatively large summation value).
In order that the control signal is present contemporaneously with the scene change at the coder 8, the frame of the signal source must be correspondingly delayed by one frame period in the buffer 7. The coder CA 022064~4 1997-0~-29 PD960037 D94/156A-Ha-300197 8 then identifies from the control signal whether the frame present at its input belGngs to a new picture scene and, if this is the case, causes the coding algorithm to begin with a new Group of Pictures and therefore with an I-coded picture. The data-red~cei output signal is available at output 9.
In order, for example, to identify greater camera panning as such, the scene detector 10 can also carry out internally a global video signal prediction in a global predictor 11. Such a global predictor is described, for example, in EP-A-0 414 113. For this purpose, the input signal and the output signal of memory 4 are fed to the predictor 11. If this predictor identifies global motion in the picture, the subtraction stage 5, the threshold value decision circuit 6 and/or the coder 8 are controlled in such a way that the coder 8 does not deviate from the nGrmal I-picture sequence. The global motion parameters can be forwarded by the predictor 11 to the coder 8. The advantage in doing this is that pictures with global motion can be coded with good efficiency as P or B
pictures and, therefore, the number of I-coded pictures and hence the data rate do not have to be increased unnecessarily, that is to say that detectable (global) camera panning is not interpreted as a scene change. It is advantageously possible for the result of this global prediction to be included during "normal"
prediction in the coder. This enables the prediction in the coder 8 to be simplified or improved.
In further exemplary embodiments of the invention, the storage capacity for the scene detector can be reduced. A scene change can also be identified on the basis of fields. The memories 4 and 7 are then field memories and the pixel values of two adjacent fields are then correspondingly processed with one another in the subtractor 5. The two fields may also originate from adjacent frames.
CA 022064~4 l997-0~-29 PD960037 D94/156A-Ha-300197 A different or a further reduction in the storage capacity is possible with the aid of video data reduction upstream of the input of memory 4 and possibly also buffer 7, which can be carried out by means of horizontal and/or vertical low-pass filtering of the video data in conjunction wlth subsa~.pllng the corresponding direction.
In the case of a scene change, either the I
coding can be additionally inserted into the sequence present. Alternatively, the normal sequence can be continued again from the scene change, in other words, for example, every 12 pictures an I picture, the picture with the scene change being the first of these I pictures.
The invention is not just restricted to the studio sector, but can also be employed in the consumer sector on data media, in particular optical disks, which contain video data coded according to the invention. For example, the invention can be used to improve the quality of the recording of video signals on a digital home video recorder or DVD recorder in the manner illustrated. In this case, the scene de-ector not to be regarded as part of the picture generator, but rather is implemented as an additional circu't element in the recording unit.
In the case of received video signal which are coded with a fixed GOP length, these signals may first of all be decoded and then encoded with a variable GOP
length for the recording. During the recording of digital video signals which are coded according to the invention, are provided with corresponding, variable GOP length information and are publicly transmitted, or in the case of the reproduction only of prerecorded data media, the scene detector in the recording unit can then be omitted or it is possible not to evaluate its output signal for the recording.
The invention is not restricted to the MPEG2 or MPEG1 coding standard. The invention can be applied to PD960037 D94/156A-Ha-300197 all coding processes which perform segmentation of the video data into groups of pictures, for example MPEG4.
Prior art For future digital television broadcasting (DVB = Digital Video Broadcasting) and the interactive communications services associated therewith, vldeo data must be substantially reduced in terms of tr.e volume of data by means of suitable coding devices.
This step is necessary in order to be able to transmit more programmes via existing channels or to communicate moving picture sequences in already existing narrow-band transmission paths. One coding method provided for this purpose is the MPEG2 standard (ISO/IEC 13818).
Invention In order to obtain the highest possible compression factor during coding, the input pictures are combined in Groups of Pictures (GOP) in the case of MPEG. The individual pictures are coded differently within such a Group of Pictures. According to MPEG, a Group always consists of one intraframe-coded frame (I frame) as well as normally a plurality of P frames (predicted frame) and/or B ~rames (bidlrectlona y calculated frames), it being true here as well as in the following text that "frame" may also be replaced by "field".
The data rate necessary for transmitting a frame from this Group depends on the relevant frame type (I, P or B) as well as the current picture contents. The largest relative volume of data within a Group of Pictures is allotted to the I frames. They contain all the data required for complete reconstruction in the decoder. In contrast, P frames are predicted from I frames or a preceding P frame, that is to say the presence of a complete I frame in the relevant Group of Pictures is CA 022064~4 1997-0~-29 PD960037 D94/156A-Ha-300197 necessary for the reconstruction of the P frames at the receiving end. For this purpose, it is then necessary to code only the difference from the preceding I or P
frame. B frames, on the other hand, are essentially calculated (interpolated) from already reconstructed I
or P frames. The volume of data which must be transmitted for a B frame is correspondingly low.
Certain picture types may also contain individual macroblocs of other picture types, for example macroblocs may occur in P and B pictures at picture excerpts which could otherwise be coded only with insufficient efficiency.
Although the above-described classification of the frames into different frame types permits a very high coding efficiency, it imparts to the different frame types different degrees of sensitivity to transmission errors. Thus, transmission or reconstruction errors within B frames remain restricted to the corresponding B frame, whereas erroneous I and P frames can affect the entire Group of Pictures (GOP). In the case of the most frequently chosen MPEG2 parameter of 12 frames per GOP, the time duration for this may last up to approximately half a second (at 50 Hz frame frequency, at 60 or 59.94 Hz frame frequency correspondingly shorter) and is thus very disturbing to a viewer.
A similar effect regarding error degradation may also occur when, during the coding of a feature film, a change in the picture scene occurs within a Group of Pictures. In this case, no rational basis for the prediction of the B and P frames exists for the current Group of Pictures, rather the first picture of the new scene is largely coded with intraframe macroblocs, on account of the internal control of the coder. Since the allocated volume of data for a P frame is not large enough to intraframe-code large portions of the picture with good quality, the reconstruction result in the decoder will remain unsatisfactory. Only in the following Group of Pictures do stable conditions - CA 022064~4 1997-0~-29 PD960037 D94/156A-Ha-300197 .
exist once again for the coding process, which permit satisfactory reconstruction.
Previous coding processes for data reduction are ~ei on feeding the volume of data !picture sequerlces;, which originates from a film scanner, for example, tC' an MPEG coder which continuously generates a data-reduced bit stream. In this concept, scene cuts of the original film coincide completely arbitrarily with a frame type determined by the coder, which may lead to the above-described error degradation within a Group of Pictures.
The invention is based on the object of specifying a method in which the coding process ls synchronized with a scene change that is present. This object is achieved by means of the method specified in Claim 1.
The invention is based on the further object of specifying an apparatus for application of the method according to the invention. This bject lS achievel r, ,, means of the apparatus specified ir. Claim 6.
For this purpose, a scene detector is connected between the picture generator (film scanner, camera, recording device or another signal source) and the coder. The said scene detector generates a suitable control signal and causes the coding process, in the event of a scene change, to begin with a new Group of Pictures, that is to say with an I-coded picture. This advantageously prevents a scene change from falling in the middle of a Group of Pictures, for example, and thus reconstruction with impaired quality from being engendered at the decoder. This measure advantageously requires no additional outlay in the decoder and consequently does not lead to an increase in the complexity and hence the costs in the end unit, that is to say a decoder in a set-top box or in a televlsion set/video recorder/DVD player (Digital VideoDisk).
In principle, the method according to the invention consists in the fact that, for coding digital CA 022064~4 1997-0~-29 PD960037 D94/156A-Ha-300197 video signals, in which, in each case with a defined sequence, an intraframe-coded picture and at least one other picture coding type for a further picture or further pictures are used in a group of successive pictures, pixel values which change greatly from one picture to another picture or greatly changing picture contents are determined in a detector and the further coding is controlled in such a way that intraframe coding is carried out for a picture having greatly changing pixel values or greatly changing picture contents, independently of the position of this picture within the group.
Advantageous developments of the method according to the invention emerge from the associated dependent claims.
In principle, the inventive apparatus for coding digital video signals, in which, in each case with a defined sequence, an intraframe-coded picture (I) and at least one other picture coding type (P, B) for a further picture or further pictures are used in a group of successive pictures, is provided with:
- a detector, which determines pixel values whlch change greatly from one picture to another picture or greatly changing picture contents;
- a coder, which is controlled by the detector in such a way that intraframe coding is carried out for a picture having greatly changing pixel values or greatly changing picture contents, independently of the position of this picture within the group.
Advantageous developments of the apparatus according to the invention emerge from the associated dependent claim.
Drawing An exemplary embodiment of the invention is described with reference to the drawing, in which:
Figure 1 shows an example of a scene-controlled MPEG
coder.
CA 022064~4 1997-0~-29 PD960037 D94/156A-Ha-300197 Exemplary embodiments The video signal is drawn from a picture generator 1, which may be a film scanner, a television camera or any desired analog picture source (for example tape recording device). This signal is first of all fed to an analog/digital converter 2 in order that digital input data can be made available for the coder.
If the signal generator which is available is already a digital signal source, the latter can be connected to the circuit arrangement via input 3. The signal at input 3 is then fed to a scene detector lu, wrlic.~.
comprises, for example, a frame memory 4, a subtractlon stage 5 and a threshold value decision circuit 6. The current frame n of the signal source is available at the input of the frame memory 4 and the preceding frame n-1 delayed by one frame period is available at the output. The sum of the absolute value differences between the pixels of the two frames, for example, is calculated by means of the subtraction stage 5. This summation value is then fed to the threshold value decision circuit 6. Depending on this summation value, the threshold value decision circuit generates a control signal for the MPEG coder 8. The characteristic of the threshold value decision circuit is in this case dimensioned in such a way that differences in the same picture scene which are caused, for example, by moving objects or by slow camera panning trigger no cGntrol signal or a first control signal (in the case of a relatively small summation value), but that a scene change which is characterized by completely different picture information leads to an unambiguous control signal or a second control signal (in the case of a relatively large summation value).
In order that the control signal is present contemporaneously with the scene change at the coder 8, the frame of the signal source must be correspondingly delayed by one frame period in the buffer 7. The coder CA 022064~4 1997-0~-29 PD960037 D94/156A-Ha-300197 8 then identifies from the control signal whether the frame present at its input belGngs to a new picture scene and, if this is the case, causes the coding algorithm to begin with a new Group of Pictures and therefore with an I-coded picture. The data-red~cei output signal is available at output 9.
In order, for example, to identify greater camera panning as such, the scene detector 10 can also carry out internally a global video signal prediction in a global predictor 11. Such a global predictor is described, for example, in EP-A-0 414 113. For this purpose, the input signal and the output signal of memory 4 are fed to the predictor 11. If this predictor identifies global motion in the picture, the subtraction stage 5, the threshold value decision circuit 6 and/or the coder 8 are controlled in such a way that the coder 8 does not deviate from the nGrmal I-picture sequence. The global motion parameters can be forwarded by the predictor 11 to the coder 8. The advantage in doing this is that pictures with global motion can be coded with good efficiency as P or B
pictures and, therefore, the number of I-coded pictures and hence the data rate do not have to be increased unnecessarily, that is to say that detectable (global) camera panning is not interpreted as a scene change. It is advantageously possible for the result of this global prediction to be included during "normal"
prediction in the coder. This enables the prediction in the coder 8 to be simplified or improved.
In further exemplary embodiments of the invention, the storage capacity for the scene detector can be reduced. A scene change can also be identified on the basis of fields. The memories 4 and 7 are then field memories and the pixel values of two adjacent fields are then correspondingly processed with one another in the subtractor 5. The two fields may also originate from adjacent frames.
CA 022064~4 l997-0~-29 PD960037 D94/156A-Ha-300197 A different or a further reduction in the storage capacity is possible with the aid of video data reduction upstream of the input of memory 4 and possibly also buffer 7, which can be carried out by means of horizontal and/or vertical low-pass filtering of the video data in conjunction wlth subsa~.pllng the corresponding direction.
In the case of a scene change, either the I
coding can be additionally inserted into the sequence present. Alternatively, the normal sequence can be continued again from the scene change, in other words, for example, every 12 pictures an I picture, the picture with the scene change being the first of these I pictures.
The invention is not just restricted to the studio sector, but can also be employed in the consumer sector on data media, in particular optical disks, which contain video data coded according to the invention. For example, the invention can be used to improve the quality of the recording of video signals on a digital home video recorder or DVD recorder in the manner illustrated. In this case, the scene de-ector not to be regarded as part of the picture generator, but rather is implemented as an additional circu't element in the recording unit.
In the case of received video signal which are coded with a fixed GOP length, these signals may first of all be decoded and then encoded with a variable GOP
length for the recording. During the recording of digital video signals which are coded according to the invention, are provided with corresponding, variable GOP length information and are publicly transmitted, or in the case of the reproduction only of prerecorded data media, the scene detector in the recording unit can then be omitted or it is possible not to evaluate its output signal for the recording.
The invention is not restricted to the MPEG2 or MPEG1 coding standard. The invention can be applied to PD960037 D94/156A-Ha-300197 all coding processes which perform segmentation of the video data into groups of pictures, for example MPEG4.
Claims (8)
1. Method for coding (8) digital video signals, in which, in each case with a defined sequence, an intraframe-coded picture (I) and at least one other picture coding type (P, B) for a further picture or further pictures are used in a group (GOP) of successive pictures, characterized in that pixel values which change greatly from one picture to another picture or greatly changing picture contents are determined in a detector (10) and the further coding (8) is controlled in such a way that intraframe coding is carried out for a picture having greatly changing pixel values or greatly changing picture contents, independently of the position of this picture within the group (GOP).
2. Method according to Claim 1, wherein, in the detector (10), the sum of the absolute value differences between the pixels of two adjacent frames (n, n-1) or fields is formed (5) and compared (6) with a threshold value in order to generate a control signal for the subsequent coding (8).
3. Method according to Claim 1 or 2, wherein, prior to the formation of the absolute value differences, the video data are horizontally and/or vertically low-pass-filtered and subsampled in the corresponding direction.
4. Method according to one or more of Claims 1 to 3, wherein, in the detector (10), a search is made for global motion parameters by means of prediction and, if such parameters are present, no additional intraframe coding is effected.
5. Method according to Claim 4, wherein the global motion parameters are used or taken into account during the further coding (8).
6. Apparatus for coding (8) digital video signals, in which, in each case with a defined sequence, an intraframe-coded picture (I) and at least one other picture coding type (P, B) for a further picture or further pictures are used in a group (GOP) of successive pictures, characterized by:
- a detector (10), which determines pixel values which change greatly from one picture to another picture or greatly changing picture contents;
- a coder (8), which is controlled by the detector in such a way that intraframe coding is carried out for a picture having greatly changing pixel values or greatly changing picture contents, independently of the position of this picture within the group (GOP).
- a detector (10), which determines pixel values which change greatly from one picture to another picture or greatly changing picture contents;
- a coder (8), which is controlled by the detector in such a way that intraframe coding is carried out for a picture having greatly changing pixel values or greatly changing picture contents, independently of the position of this picture within the group (GOP).
7. Apparatus according to Claim 6, wherein the detector (10) contains a predictor (11) which determines global motion parameters and, if such parameters are present, controls the coder in such a way that no additional intraframe coding is effected therein.
8. Data medium, in particular optical disk, which contains video data which are coded using a method according to Claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19626108A DE19626108A1 (en) | 1996-06-28 | 1996-06-28 | Digital image signal coding method e.g. for Digital Video Broadcasting |
| DE19626108.2 | 1996-06-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2206454A1 true CA2206454A1 (en) | 1997-12-28 |
Family
ID=7798375
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002206454A Abandoned CA2206454A1 (en) | 1996-06-28 | 1997-05-29 | Method and apparatus for coding digital video signals |
Country Status (10)
| Country | Link |
|---|---|
| EP (1) | EP0831650A3 (en) |
| JP (1) | JPH1084545A (en) |
| KR (1) | KR980007748A (en) |
| CN (1) | CN1171017A (en) |
| BR (1) | BR9703787A (en) |
| CA (1) | CA2206454A1 (en) |
| DE (1) | DE19626108A1 (en) |
| ID (1) | ID17033A (en) |
| MX (1) | MX9704785A (en) |
| ZA (1) | ZA975424B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19806913A1 (en) | 1998-02-19 | 1999-08-26 | Cit Alcatel | Method for generating an entry point into an image data stream and device for carrying out the method |
| JP2005026747A (en) * | 2003-06-30 | 2005-01-27 | Matsushita Electric Ind Co Ltd | Filter processing apparatus, image coding apparatus, and method therefor |
| CN100379283C (en) * | 2004-04-29 | 2008-04-02 | 明基电通股份有限公司 | Method for dynamically determining video data, storage media, and video transmission device |
| JP4541825B2 (en) * | 2004-10-15 | 2010-09-08 | キヤノン株式会社 | Video encoding apparatus and control method thereof |
| CN100414999C (en) * | 2005-03-07 | 2008-08-27 | 明基电通股份有限公司 | Method and device for processing video signal |
| CN100471273C (en) * | 2006-07-17 | 2009-03-18 | 四川长虹电器股份有限公司 | Digital video frequency wireless transmitting system |
| EP2107811A1 (en) * | 2008-03-31 | 2009-10-07 | British Telecmmunications public limited campany | Encoder |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3338460B2 (en) * | 1991-05-09 | 2002-10-28 | ソニー株式会社 | Video signal encoding device and video signal encoding method |
| DE69229705T2 (en) * | 1991-05-23 | 1999-12-23 | Japan Broadcasting Corp | METHOD FOR DETECTING A MOTION VECTOR AND DEVICE THEREFOR AND SYSTEM FOR PROCESSING AN IMAGE SIGNAL WITH THIS DEVICE |
| AU657510B2 (en) * | 1991-05-24 | 1995-03-16 | Apple Inc. | Improved image encoding/decoding method and apparatus |
| US5488482A (en) * | 1992-01-29 | 1996-01-30 | Mitsubishi Denki Kabushiki Kaisha | High-efficiency encoder and video information recording/reproducing apparatus |
| JP3093494B2 (en) * | 1992-11-18 | 2000-10-03 | 株式会社東芝 | Diversity signal processing device |
| US5614952A (en) * | 1994-10-11 | 1997-03-25 | Hitachi America, Ltd. | Digital video decoder for decoding digital high definition and/or digital standard definition television signals |
| BE1007807A3 (en) * | 1993-11-30 | 1995-10-24 | Philips Electronics Nv | Apparatus for encoding a video signal. |
| US5592226A (en) * | 1994-01-26 | 1997-01-07 | Btg Usa Inc. | Method and apparatus for video data compression using temporally adaptive motion interpolation |
| US5734419A (en) * | 1994-10-21 | 1998-03-31 | Lucent Technologies Inc. | Method of encoder control |
| JP3191583B2 (en) * | 1994-12-12 | 2001-07-23 | ソニー株式会社 | Information decryption device |
| US5508750A (en) * | 1995-02-03 | 1996-04-16 | Texas Instruments Incorporated | Encoding data converted from film format for progressive display |
-
1996
- 1996-06-28 DE DE19626108A patent/DE19626108A1/en not_active Withdrawn
-
1997
- 1997-05-28 ID IDP971784A patent/ID17033A/en unknown
- 1997-05-29 CA CA002206454A patent/CA2206454A1/en not_active Abandoned
- 1997-06-14 EP EP97109716A patent/EP0831650A3/en not_active Withdrawn
- 1997-06-19 ZA ZA975424A patent/ZA975424B/en unknown
- 1997-06-23 KR KR1019970026484A patent/KR980007748A/en not_active Application Discontinuation
- 1997-06-25 JP JP9168984A patent/JPH1084545A/en active Pending
- 1997-06-25 MX MX9704785A patent/MX9704785A/en unknown
- 1997-06-27 CN CN97113972A patent/CN1171017A/en active Pending
- 1997-06-30 BR BR9703787A patent/BR9703787A/en active Search and Examination
Also Published As
| Publication number | Publication date |
|---|---|
| ID17033A (en) | 1997-12-04 |
| KR980007748A (en) | 1998-03-30 |
| MX9704785A (en) | 1997-12-31 |
| JPH1084545A (en) | 1998-03-31 |
| CN1171017A (en) | 1998-01-21 |
| EP0831650A3 (en) | 2000-12-06 |
| EP0831650A2 (en) | 1998-03-25 |
| DE19626108A1 (en) | 1998-01-08 |
| ZA975424B (en) | 1998-12-21 |
| BR9703787A (en) | 1998-11-03 |
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