CN102547307A - Digital video amplitude limiting method for analog broadcasting TV signal - Google Patents
Digital video amplitude limiting method for analog broadcasting TV signal Download PDFInfo
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- CN102547307A CN102547307A CN2011104440897A CN201110444089A CN102547307A CN 102547307 A CN102547307 A CN 102547307A CN 2011104440897 A CN2011104440897 A CN 2011104440897A CN 201110444089 A CN201110444089 A CN 201110444089A CN 102547307 A CN102547307 A CN 102547307A
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Abstract
The invention relates to a digital video amplitude limiting method for analog broadcasting TV signals. The system used in the method comprises an audio/video decoder, an audio data cache, an amplitude detector, an amplitude limiter, and an audio/video encoder. The method comprises receiving an audio/video file, and decoding; amplitude detecting; amplitude limiting; and audio/video encoding. The invention can predict the level after modulation within the making domain and accordingly determine whether the video data result in over-standard level after modulation, so as to, after editing and making of a TV program file, detect the video data of the file, limit the over-standard pixel and solve the over-standard problem before D/A (digital to analog) conversion. The inventive method is implemented pixel by pixel, only limits amplitude of the over-standard pixel and does not process the other pixels, so as to minimize the influence on video data amplitude limiting, without causing the problem of overall compression due to local over-standard.
Description
Technical field
The present invention relates to a kind of method of digital video amplitude limit of analog television broadcast signal, is a kind of method of digital video signal processing, is a kind of preceding method that digital video signal is handled of analog television broadcast signal emission that is used for.
Background technology
Analog television broadcast signal need be modulated to baseband video signal on the carrier frequency before emission.For various reasons, in the process of modulation, the phenomenon that vision signal exceeds standard can appear; The amplitude that is the signal of telecommunication is too high or too low, and the signal quality after the modulation can be affected, after television set receives signal; Produce demodulation distortion, image quality descends, and finally influences spectators' the impression of watching.Therefore, the distortion how effective erasure signal exceeds standard and brought becomes a major issue.
To the problem that signal amplitude exceeds standard, generally adopt the mode of amplitude compression.This is after analog-modulated, before the emission signal amplitude is detected, and when finding that signal amplitude exceeds standard, the amplitude of the analog signal after the modulation is carried out reduced overall.But owing to be the compression of after modulation, carrying out, this method exists a lot of problems.In the actual signal processing procedure, the video data that exceeds standard often just continues very short a period of time, even is some limited pixels.But existing method is after modulation, signal to be carried out the overall magnitude restriction, therefore can cause the whole reduction of signal amplitude, and receiving terminal video pictures total quality is descended.The video pictures total quality is descended, and is a kind of method that loses more than gain.
Summary of the invention
Be to solve prior art problems, the objective of the invention is to propose a kind of method of digital video amplitude limit of analog television broadcast signal.Described method is after the digital video programs documenting finishes; Promptly all pixels to the video image in the digital video programs file detect; Find out the pixel that exceeds standard, and these pixels are carried out the amplitude limit compression, to guarantee the total quality of video image.
The objective of the invention is to realize like this: a kind of method of digital video amplitude limit of analog television broadcast signal; The system that said method is used comprises: audio/video decoder, voice data buffer memory, range detector, amplitude limiter, audio/video coder, and the step of said method is following:
Receive the step of audio-video document and decoding: be used for receiving pending audio-video document and pending audio-video document be decoded as voice data and video data at audio/video decoder; Then voice data is sent into the voice data buffer memory, simultaneously video data is sent into range detector and detect;
The step of amplitude detection: be used for detection and record that whether range detector exceeds standard to the pixel data amplitude of carrying out of video data, the situation of afterwards video data being sent in the amplitude limiter and being notified the amplitude limiter video data to exceed standard;
The step of amplitude limit: be used for amplitude limiter the video data that exceeds standard is carried out amplitude limit, the data that do not exceed standard are not processed, the video data of amplitude limiter output is sent into audio/video coder;
The step of audio/video coding: be used for audio/video coder and video data of receiving and the voice data that extracts from the voice data buffer memory are encoded form the audio-video document after handling, accomplish processing procedure.
The beneficial effect that the present invention produces is: the characteristics that the present invention is directed to this locality of data that exceeds standard; In making the territory, promptly dope modulation level afterwards; And judge video data in view of the above and whether can cause that the level after the modulation exceeds standard, and then after television program file was accomplished editing, promptly the video data to this document detected; Pixel to exceeding standard limits, and the problem that will exceed standard solves before D/A conversion prerequisite.Method of the present invention is undertaken by pixel, only the pixel that exceeds standard is done amplitude limit, and what do not exceed standard does not then deal with.Like this; The present invention has not only prevented the problem that modulation exceeds standard from the source; But also will be reduced to minimum to the influence of video data amplitude restriction; Can not produce and original the sort ofly to the problem that integral body is compressed, kept original video information because of local exceeding standard to greatest extent, the influence of impression is finally watched in minimal reduction to spectators.
Description of drawings
Below in conjunction with accompanying drawing and embodiment the present invention is described further.
Fig. 1 is the flow chart of the embodiment of the invention one said method;
Fig. 2 is the amplitude detection flow chart of the embodiment of the invention two said methods.
Embodiment
Embodiment one:
Present embodiment is a kind of method of digital video amplitude limit of analog television broadcast signal, and the system that said method is used comprises: audio/video decoder, voice data buffer memory, range detector, amplitude limiter, audio/video coder.This system can be a hardware, also can be software.If hardware can be designed as special IC chip, or use the chip of similar programmable gate array.If software, can be arranged in the server that audio frequency and video handle and use software to form audio/video decoder, voice data buffer memory, range detector, amplitude limiter, audio/video coder, realize processing procedure.The video input of the said system of present embodiment, output all are digital fileizations.
Audio/video decoder: this module is positioned at input interface, and the audio file of looking of documentation is decoded, and for follow-up amplitude detection module provides YCbCr 4:2:2 the video data of form, simultaneously voice data is separated from file.
Audio/video coder: video data and the voice data before separated that this module will be passed through the YCbCr 4:2:2 form of amplitude limiting processing are re-encoded as video file output.Postpone because amplitude limit operation can be introduced, so voice data done certain buffer delay, to keep in time synchronous of voice data and video data.
Range detector: this module is pursued the detection of pixel to video data, calculates that this pixel data can or can not cause the problem of exceeding standard after modulation.And the signalisation amplitude compression module whether current pixel is exceeded standard.
Amplitude limiter: when definite this pixel can exceed standard after modulation, the amplitude compression module was carried out amplitude compression to this pixel data; When this pixel data can not exceed standard after modulation, the amplitude compression module was left intact to this pixel data.
The said procedure of present embodiment is as shown in Figure 1, and step is following:
Receive the step of audio-video document and decoding: be used for receiving pending audio-video document and at audio/video decoder pending audio-video document is decoded as voice data and video data; Then voice data is sent into the voice data buffer memory, simultaneously video data is sent into range detector and detect.
The step of amplitude detection: be used for detection and record that whether range detector exceeds standard to the pixel data amplitude of carrying out of video data, the situation of afterwards video data being sent in the amplitude limiter and being notified the amplitude limiter video data to exceed standard.Present embodiment adopts a kind of elder generation to convert single pixel data into yuv format, calculates the aberration vector then, calculates the level peak value after modulating afterwards, finally judges according to preset threshold whether this pixel data exceeds standard.The mode that present embodiment adopted is the detection to single pixel, therefore can avoid entire image is imposed uniformity without examining individual cases, and forms overall image quality and descends.
The step of amplitude limit: be used for amplitude limiter the video data that exceeds standard is carried out amplitude limit, the video data behind the amplitude limit is sent into audio/video coder.The mode of amplitude limit also has multiple, for example, can compress luminance signal, also can compress color difference signal, can also compress YUV simultaneously.The amplitude of exceeding standard of considering the data that exceed standard can't be too big; Compression chromatism signal relates to two variablees; And because the relation of the sub-sampling form of 4:2:2, also can have influence on the pixel of adjacent shared a pair of color difference signal, present embodiment is taked the easiest a kind of mode: brightness data is compressed; Thereby reach the purpose of compression, received good effect in the reality.
The step of audio/video coding: be used for audio/video coder and video data of receiving and the voice data that extracts from the voice data buffer memory are encoded form the audio-video document after handling, accomplish processing procedure.
The concrete data of the step of present embodiment amplitude detection and amplitude limit for example.Get one group of pixel data: Y=168, Cb=44, Cr=135.Wherein data precision is 8, and numerical value is the decimal system.
At first, calculate Y ' UV, this process is obtained a result through a fixing reduction formula:
Y’=152，U=-73.4255，V=8.6101。
Then, calculate the absolute value of chrominance vector C, | C|=(U
2+ V
2)
1/2:
|C|=73.9286
At last, calculating upper limit A
+=f
1(Y ')+f
2(| C|)/2 with lower limit A
-=f
1(Y ')-f
2(| C|)/2.Function f
1(Y ') and f
2(| C|) be voltage magnitude (with the millivolt is unit, and unit symbol is mV), wherein f through the numerical value conversion analog domain of numeric field
2(| C|) carrier chrominance signal is sinusoidal wave during the modulation of representative, consider positive and negative, will be during calculating divided by 2.Through calculating A
+Be 717.234 mV, and A
-Be 254.4410 mV.With amplitude range-230 mV ~ 700 mV is example, and the upper limit has surpassed.At this moment, with A
+Be limited to 700 mV, counter rolling back calculates y
h'=146, then Y=y
h'+16=162.
Like this, original Y=168, Cb=44, one group of pixel data of Cr=135 through behind the amplitude limit, has become Y=162, Cb=44, Cr=135.Change for Y is also little.And these group data are in modulation afterwards, and amplitude will be at 700 mV, and can not exceed standard.
Embodiment two:
Present embodiment is the improvement of embodiment one, is the refinement of embodiment one about amplitude detection.The process of the said amplitude detection of present embodiment is as shown in Figure 2, comprises following substep:
The Y of a pixel, Cb, Cr pixel data in the extraction document; Convert into this pixel data into Y ' the UV data in YUV territory, Y '=Y-16, U=[(Cb-128)/0.564] * 0.493; V=[(Cr-128)/0.713] * 0.877 sees standard I TU-R BT.601-4 for details.
Calculate the absolute value of chrominance vector C | C|, brightness value corresponding simulating level amount f
1(Y '), chromatic value corresponding simulating level amount f
2(| C|).Wherein:
|C|=(U
2+V
2)
1/2，
f
1(Y’)=?Y’×3.1963?，
f
2(|C|)=?|C|×6.26。
Calculate the positive level peak A after modulating
+With the negative level peak A
-A wherein
+=f
1(Y ')+f
2(| C|)/2, A
-=f
1(Y ')-f
2(| C|)/2.In when modulation, carrier chrominance signal is added to the form of sine wave on the luminance signal, have positive and negative, so will be divided by 2.
Two level peak values that calculate are done comparison with the upper limit H and the lower limit L of threshold value respectively, judge whether to exceed standard, whether the upper limit A that exceeds standard is promptly arranged
+>H or the lower limit A that exceeds standard
-<l.If exceed standard then be labeled as and exceed standard and mark that the upper limit exceeds standard or lower limit exceeds standard; If do not exceed standard then do not make marks; Get back to the substep of " extract Y, Cb, the Cr data of a pixel in the file, this pixel data is converted into Y ' the UV data in YUV territory " then.
It is YCbCr 4:2:2 form that present embodiment is set the pixel data that decoding is come out from file, and extended formatting can be converted into YCbCr 4:2:2 form through necessary conversion, also can use.And actual what finally modulate is yuv format, and a fixing matrix conversion relation (seeing standard I TU-R BT.601-4 for details) is arranged between the two:
Y’=Y-16;
U=[(Cb-128)/0.564]×0.493;
V=[(Cr-128)/0.713]×0.877;
Y component (when data precision was 8, the two deviation numerically was 16) in order to distinguish the two has specially marked the UV into Y ' with YUV among Fig. 2, to show differentiation.Afterwards according to two color difference components U and V, calculate aberration vector C absolute value (| C|=(U
2+ V
2)
1/2).During final the modulation, be that vector C is modulated on the Y ', obtain analog level f
1(Y ') and f
2(| C|):
f
1(Y’)=Y’×3.1963
f
2(|C|)=|C|×6.26;
Wherein coefficient 3.1963 and 6.26 has embodied the mapping relations of numeric field and analog domain.At numeric field, be example with 8 bit accuracy, the scope of Y is 16 ~ 235, then the scope of Y ' is 0 ~ 219, corresponds on the full width of cloth level of simulation of 700mV, is equivalent to 1 corresponding 3.1963mV of numeric field; In like manner, the scope of Cb and Cr is 16 ~ 240, and then can extrapolate the scope of U and V and C, and coefficient 6.26 also is through the coefficient of calculating out, because positive and negative branch is arranged at Y ' and C C when analog domain superposes, and therefore also will be divided by a coefficient 2 in the back.
When modulation, carrier chrominance signal corresponding simulating level f
2(| C|) with the form of the sine wave luminance signal corresponding simulating level f that is added to
1(Y ') on, the possible peak that therefore can calculate certain pixel modulation back analog level is f
1(Y ')+f
2(| C|)/2, possible minimum is f
1(Y ')-f
2(| C|)/2.After calculating the highest and minimum of level, can judge whether to have exceeded standard based on preset threshold.This threshold value is the open user's of giving, and the user can oneself set as required.It is 700mV that present embodiment is recommended the upper limit of acquiescence, and lower limit is-230mV.
Embodiment three:
Present embodiment is the improvement of the foregoing description, is the refinement of the foregoing description about amplitude limit.The described amplitude limit of present embodiment comprises following substep:
If judging the upper limit exceeds standard, then give A with the boundary level value assignment of maximum possible after this pixel modulation
+, i.e. A
+=f
1(y
h')+f
2(C)=H.According to the anti-intensity level f that pushes away of equality
1(y
h'), f then
1(y
h')=H-f
2And then calculate the brightness value y behind this amplitude limit (C)/2, in the YUV territory
h', revising this pixel is Y=y at the brightness value of YCbCr color gamut space
h'+16.
If lower limit exceeds standard, just establish A
-=f
1(y
l')-f
2(C)=L, and then calculate the intensity level f behind the lower limit amplitude limit according to equality
1(y
l'), f then
1(y
l')=H-f
2(C)/2, calculate the brightness value y in this YUV territory behind the lower limit amplitude limit
l', revising this pixel is Y=y at the brightness value of YCbCr color gamut space
l'+16.
For judging the pixel that does not exceed standard, do not process.
Said method can be interpreted as: as the f of certain pixel value
1(Y ')+f
2(| C|)/2 exceed the upper limit or f
1(Y ')-f
2(| C|)/2 exceed down in limited time, need compress pixel data.Processing method is: the f that will exceed standard
1(Y ')+f
2(| C|)/2 (or f
1(Y ')-f
2(| C|)/2) is made as higher limit (or lower limit), anti-then the YCbCr that calculates back.Can adjust Y ', also can adjust, perhaps simultaneously the two adjusted C.Because the adjustment to C relates to two color difference components,, only Y is adjusted in the system at present from handling simple consideration.In the reality, because the amplitude of pixel of exceeding standard can't be big especially, and the amplitude of only Y being adjusted is also not too large, and this influence also can be very little, in the visual error range of human eye, is acceptable.From other aspect, because pixel data YCbCr employing is the sub-sampling form of 4:2:2, the adjacent shared a pair of CbCr of two pixels in order to make the amplitude limit influence not diffuse into neighbor, also should only compress Y.
Embodiment four:
Present embodiment is to implement two, three improvement, is the refinement of embodiment two, three about upper limit H and lower limit L.Described upper limit H of present embodiment and lower limit L can set by the user is artificial, mate with the parameter of transmitter to make things convenient for the user.That default is one group of accepted value: H=700mV at present, L=-230mV.
What should explain at last is; Below only unrestricted in order to technical scheme of the present invention to be described; Although the present invention is specified with reference to the preferred arrangement scheme; Those of ordinary skill in the art should be appreciated that and can make amendment or be equal to replacement technical scheme of the present invention (such as detecting and the method for amplitude limit, the front and back sequential scheduling of step), and do not break away from the spirit and the scope of technical scheme of the present invention.
Claims (4)
1. the method for the digital video amplitude limit of an analog television broadcast signal, the system that said method is used comprises: audio/video decoder, voice data buffer memory, range detector, amplitude limiter, audio/video coder is characterized in that the step of said method is following:
Receive the step of audio-video document and decoding: be used for receiving pending audio-video document and at audio/video decoder pending audio-video document is decoded as voice data and video data; Then voice data is sent into the voice data buffer memory, simultaneously video data is sent into range detector and detect;
The step of amplitude detection: be used for detection and record that whether range detector exceeds standard to the pixel data amplitude of carrying out of video data; The situation of afterwards video data being sent in the amplitude limiter and being notified the amplitude limiter video data to exceed standard comprises that what whether exceed standard and exceed standard is the upper limit or lower limit;
The step of amplitude limit: be used for amplitude limiter the video data that exceeds standard is carried out amplitude limit, the data that do not exceed standard are not processed, the video data of amplitude limiter output is sent into audio/video coder;
The step of audio/video coding: be used for audio/video coder and video data of receiving and the voice data that extracts from the voice data buffer memory are encoded form the audio-video document after handling, accomplish processing procedure.
2. method according to claim 1 is characterized in that, the step of described amplitude detection comprises following substep:
The YCbCr pixel data of a pixel in the extraction document converts this pixel data to Y ' the UV data in YUV territory;
Calculate the absolute value of chrominance vector C | C|, brightness value corresponding simulating level amount f
1(Y '), chromatic value corresponding simulating level amount f
2(| C|);
Calculate the positive level peak A after modulating
+With the negative level peak A
-
Two level peak values that calculate are done comparison with the upper limit H and the lower limit L of threshold value respectively; Judge whether to exceed standard; If exceed standard then be labeled as that to exceed standard and mark what exceed standard be the upper limit or lower limit; Do not exceed standard if do not exceed standard then be labeled as, get back to the substep of " extract the YCbCr data of a pixel in the file, this pixel data is converted into Y ' the UV data in YUV territory " then.
3. method according to claim 1 and 2 is characterized in that, the step of described amplitude limit comprises following substep:
If judging the upper limit exceeds standard, then give A with the boundary level value assignment of maximum possible after this pixel modulation
+, i.e. A
+=f
1(y
h')+f
2(C)=H;
According to the anti-intensity level f that pushes away of equality
1(y
h'), f then
1(y
h')=H-f
2And then calculate the brightness value y behind this amplitude limit (C)/2, in the YUV territory
h', revising this pixel is Y=y at the brightness value of YCbCr color gamut space
h'+16;
If lower limit exceeds standard, just establish A
-=f
1(y
l')-f
2(C)=L, and then calculate the intensity level f behind the lower limit amplitude limit according to equality
1(y
l'), f then
1(y
l')=H-f
2(C)/2, calculate the brightness value y in this YUV territory behind the lower limit amplitude limit
l', revising this pixel is Y=y at the brightness value of YCbCr color gamut space
l'+16;
For judging the pixel that does not exceed standard, do not process.
4. according to the method for claim 3, it is characterized in that: described upper limit H and lower limit L set by the user is artificial; Described H=700mV, L=-230mV.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103472810A (en) * | 2013-09-29 | 2013-12-25 | 贵州电力试验研究院 | Amplitude limiting method of multi-execution-loop control system |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1323488A (en) * | 1998-09-01 | 2001-11-21 | 米克罗纳斯慕尼黑有限公司 | Circuit for controlling luminance signal amplitude |
| US6614489B1 (en) * | 1999-07-30 | 2003-09-02 | Sony United Kingdom Limited | Method of processing signals and apparatus for signal processing |
-
2011
- 2011-12-27 CN CN201110444089.7A patent/CN102547307B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1323488A (en) * | 1998-09-01 | 2001-11-21 | 米克罗纳斯慕尼黑有限公司 | Circuit for controlling luminance signal amplitude |
| US6614489B1 (en) * | 1999-07-30 | 2003-09-02 | Sony United Kingdom Limited | Method of processing signals and apparatus for signal processing |
Non-Patent Citations (1)
| Title |
|---|
| 周斌: "高清电视节目拍摄过程中的质量控制", 《视听技术》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103472810A (en) * | 2013-09-29 | 2013-12-25 | 贵州电力试验研究院 | Amplitude limiting method of multi-execution-loop control system |
| CN103472810B (en) * | 2013-09-29 | 2016-02-10 | 贵州电力试验研究院 | A kind of amplitude limit method performing loop control system more |
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