TW200428880A - Method and apparatus for moving picture compression rate control using bit allocation with initial quantization step size estimation at picture level - Google Patents

Abstract

A method and apparatus for rate control in moving picture compression. Bit allocation with initial quantization step size estimation is used at picture level. With the relationship between pre-analyzed activity of current picture to be encoded and actual complexity of previously encoded picture of the same type, a target bit budget can be allocated to the current picture in accordance with the present invention. Once the target bit budget has been determined, an initial value for an average quantization step size is estimated on the basis of the target bit budget, along with the relationship between pre-analyzed activity of current picture and actual complexity of previously coded picture. Such an initial value of the average quantization step size is useful to achieve higher picture quality at a given bit allocation.

Description

200428880 V. Description of the invention (1) [Invention = technical field of the invention] The field of data compression regards' specially refers to an applicable method and system to perform bit rate control based on the estimated initial quantization level [prior art 】 Bit representation ί = t 'The world of electronic communications is undergoing a revolution of digital digits. The main advantage of digital transmission and processing is that it can store and reproduce almost error-free data streams. ). For example, 480 video images have 29.97 diurnal surfaces per second, each frame is about ^ T Mada Line 'each scanning line needs about 480 points to be red, green, and trioxin (Plxel), but If each color component is coded at 8 bits, the bitrate is about 168 million bits per second (Mbits / S \ * video formats, the uncompressed bit rate is very high, T2 is therefore not suitable for most applications. ^ Digital audio and video integrated with computers, telecommunications networks, and consumer products: It further stimulates the information revolution, and the core of this revolution is video and audio digital compression technology. Many compression standards include algorithms based on the general knowledge of compression techniques, such as: I τ u — τ (formerly c CITT) Recommendations H.261 and H.2 6 3, and IS0 / IEC MPEG-1, MPEG-2, and MPEG-4 standards. MPEG algorithms were developed by the Moving Picture Experts Group (MPEG), which is an international standard organization (international standards) Organ i zat ion (ISO) and International Electrotechnical Commission

200428880 V. Joint Technical Committee of the Invention Description (2) (International Electrotechnical Commission, IEC) is committed to the development of video and audio compression and multiplexing expressions. These standards specify the syntax of compressed bit streams (Snta X ) And decoding methods, but for the algorithms used by the encoder, it retains a considerable amount of freedom for the novelty and diversity of the encoding. According to M PEG 'a series of video pictures (picture) divided into a sequence of group of pictures (Gop), where each group GOPwj — day starts, followed by p-day and B — day Arrangement, Figure 1 illustrates a typical set of GOPs in the order shown. The I-picture coding does not need to refer to the day-to-day or future day-to-day. The P-picture refers to the I-day or P-day-plane that is closest in time to the series of video day-days. B-day The planes are interspersed between the I-day plane and the P-day plane. And use the previous, future, or both of the immediate I-day plane and P-day plane to encode. Although several B-days can appear next to each other in succession, the other day can not be estimated by the B-days. The mother day surface has three components: a brightness value (represented by γ), a red color difference (represented by Cr), and a blue color difference (represented by Cb). For the MPEG 4 · 2: 0 format, the sampling points for each Cr and Cb component are only half of the Y component in the horizontal and vertical directions. As shown in Figure 2, the basic composition of a MPEG diurnal surface is a large block (macrobiock, expressed in MB). Taking the video of 4: 2: 0 as an example, each MB contains an array of 16x1 6 sampling points of the Y component, and two blocks of 8 X 8 sampling points of the C r and C b components, of which the Y component 1 6 X 1 6 The array of sampling points is actually composed of 4 blocks of 8x8 sampling points.

200428880 V. Description of the invention (3) The function of the flat code state is to determine which picture encoding type and which prediction mode are the best. For each daylight surface, each 8x8 block in MB is subjected to a discrete cosine transform (dlscrete c0slne transfrn) (DCT) to form an array of 8x8 conversion coefficients. The conversion coefficients are then processed by a quantization matrix =, then The zigzag (zig-zag) is used to scan the quantized results of the DCT coefficients to obtain a series of DCT coefficients, and the DCT coefficients are sequenced (= ri_e length) for encoding. You must write ^ \ =: = Type 1 type 0 is used for encoding. Type 1 type 0 is based on the previous surface, and for each plane, you need to get the following v: c ^ r) ^^ # -^ * (m〇t1〇n and its previous ^ 1-day facial towel will be encoded by the prediction error between the β β, DCT, the amount of words:? "Estimated Μ β and the current MB code. Z sub-shaped target And when VLC edits B-pictures, it is necessary to determine MB: 1 mode, F mode, and B mode to encode each body in a series of MB modes without the use of motion compensation to edit and format. 1 mode is based on MB.

Forward prediction encoding of ():-general; F mode is one-way surface-general L and vice versa, = the estimate of motion compensation (such as the picture from P gets a motion compensation box: ° white, backward prediction encoding, It is a backward-looking predictive coding, which is different from the grasping mode. It does interpolation for F, β, and FB modes. Β-branch-type motion compensation estimation. Scanning seedlings and VLC encoding. Heart Difference can use DCT, quantization, 2 words 0702-7400TWf (Nl); 90P113; Lin.ptd page 8 ^ UU428880 V. Description of the invention (4) Video encoder is important _ The main purpose of control is two: The bit rate is the bit rate. The bit rate of each MR field is from a to w to assign a code to each day and each time, T f number, so that the coded video is decoded by the decoder; the coded video The visual taste of the m. The encoder must be true 7 ::: level: then control the visible missing two at a given bit rate Rank :: Inverse: It is only after the L-intercoding, it does not exist in reality-the real p-bit used by Zhang Tianmeng 'Decision atopic (or variable. Coffee key features are adapted system using different regions with different production processes knitting 2, this technique allows each day plane

The method is quite complicated, Tumbe. However, the traditional bit rate control processing, in addition to several times to complete the video encoding using a simple mechanism to use, using two, a less adaptive quantization method can be more average. , ° and the initial quantization level, so that the quality of the day and night are here, and a single, real-time video encoding is urgently needed. The rate control technology can be used for ^ ^ # 1 ir ^ ά ^ ”, 叩, In addition, it is also expected to provide a bit manufacturing method and clothing that use the estimated initial quantization level at the day level to perform bit allocation to compress the dynamic image. [Summary of the Invention] According to the present invention, each day The allocation of target bits is based on the encoding result of the previous day surface and its pre-scoring of the current day surface to be encoded.

200428880 V. Description of the invention (5) Once the target bit is allocated, the initial value of the average quantization level will be determined accordingly. Based on the relationship between the pre-analyzed activity of the current diurnal surface and the actual complexity of the previously encoded diurnal surface, the complexity of the current picture can be estimated. This estimated current diurnal complexity is an important factor for video encoders. It is very useful to assign the target bit quota more accurately to each day. Furthermore, by using the above initial value of the average quantization level, the video encoder can output better daylight quality under the condition of a predetermined bit quota. The invention is directed to a dynamic image compression bit rate control method using an initial quantization level estimation. First calculate its full activity for the current day surface to be coded, where the current day surface is in a set of continuous day surfaces in a video sequence; then based on the current full day activity surface and this set of continuous day The ratio of the amount of activity to the complexity of the previously coded pictures of the same type in the face, estimates the current day-to-day complexity, and updates the instantaneous complexity of this group of continuous day-to-day pictures with the current day-to-day estimated complexity; The allocation of the target bit quota is based on the estimated complexity and instantaneous complexity. The initial value of the average quantization level used to encode the current daytime plane can be based on the current total activity of the daytime plane, the target bitrate, and The previously encoded day-to-day surface of the same type has its activity to complexity ratio determined; therefore, the current picture in the video sequence is encoded based on the initial value of the average quantization level. After the current diurnal coding, the ratio of the current diurnal activity to the complexity is calculated based on the current full diurnal activity, the actual number of bits consumed in the current picture, and the average quantization level of the current diurnal surface. In other words, the ratio of current day-to-day activity to complexity is directly proportional to the current day-to-day total activity, and

0702-7400TWf (Nl); 90P113; Lm.ptd Page 10 200428880 V. Description of the invention (6) Dynamic image of the other side of the consumed bit-complexity estimation-parameter update When the block is matched in the daytime, the full activity Complexity of Complex Surfaces by Momentum This group performed the daytime complexity. The average daily activity of the full-time surface of the daily surface is based on the ratio of the current daily surface to the average daily surface. The number of modes and planes, the compression bit counter of the hair, one for. The mobile code is calculated differently for this purpose and the ratio of this group of connections,. Instantly assign the target quantization level momentum, and the full activity average quantization level of complexity to the current day, which is directly proportional to the current day, and inversely proportional to the average quantization level. The rate control device quota dispatcher estimation unit is also exposed to the day and time. In the full-continuity picture of the day-to-day picture, the estimated complexity of the ten pictures is estimated, and the bit quota is given the initial value. The ratio of the standard quota is the basic amount and the current drawing level to calculate the current activity. The amount is inversely proportional to the current picture. This method uses initial quantization, including a mobile estimation and a quantized level estimation. The video sequence search is used to perform mobile activity. The previous encoder based on the model can be used to estimate the complexity, and the quota points are based on the estimated complexity of the current picture. It is used to determine by the quantization level estimation and the isotype first. The actual consumption level of the front surface of the parameter surface is compared with the ratio of the amount of activity to the complexity of the continuous consumption level of the surface. The estimation is different as early as 7L. The degree of renewal and instant encoding is based on the current pre-encoded day-to-day updater root element number and complexity. The current diurnal surface element number and the above-mentioned objects, features, and advantages of the present invention can be made more obvious and easier. 4 A better implementation is given below. Examples, and in accordance with the drawings, make 礞 y understand '

0702-7400TWf (Nl); 90P113; Lm.ptd Page 11 200428880 V. Description of the invention (7) Next ... At the beginning, the I-picture and p-day plane for prediction must be decoded in the "" encoder, By calculating the root mean square error between the original diurnal plane and the decoded diurnal plane, an objective measure of the quality of the decoded diurnal plane can be obtained. Using the root mean square difference as the distortion of the decoded diurnal plane, the decoded diurnal plane is decoded. The complexity of the surface (c 0mp 1 e X)-C is defined as follows: C = r 乂 d where r is the bit rate required to encode the day plane, and d is the distortion of the decoded day plane. In theory ' There is a proportional relationship between the average quantizati onstepslze and the degree of distortion, so the complexity of the day surface can be

Wu Yicheng ^ rxq C «-.2 where q is the average quantization level of the day surface. After the day-plane coding, the bit rate (and the number of bits consumed across the interval) and the average quantization level will be known, and the complexity of the day-plane will be obtained as a result. The complexity of the diurnal plane depends on the f of the t-plane and its coding form. The a priori technology uses a complex cliff near the coded diurnal plane to represent the current diurnal plane: 并 Degree and: IP and B _ diurnal plane respectively Maintaining its complexity to alleviate the same coding style. If the day-to-day changes of the video sequence, this method can achieve a very good effect of Bai Yiwu's gate order Ma Shishun. However, due to the book

The encoding target bit quota does not match the actual number of bits it consumes; if the content of the video sequence changes significantly, the above methods achieve consistent visual quality. Bu Yi

0702-7400TWf (Nl); 90P113; Lin.ptd Page 12 200428880 V. Description of the invention (8) According to the present invention, the current activity between the current day surface and the actual complexity of the previously coded day surface are analyzed in advance. Relationship, the complexity of the current picture will be able to estimate. Activity is a measure of its bit rate and quality after daytime coding. Assuming that the total activity A of a whole daytime surface is proportional to complexity C, then k A ~ kxC ^ — xrxq — k] xr xa 2 ^ Where k is the proportionality constant. If k 'is the activity-to-complexity ratio (ACR), the full activity A can also be expressed by the following formula: A = A CR xr xq According to the present invention, the same type Previously coded day to day to estimate A CR. Conceptually, calculate the full activity A before coding a day, and then the complexity of the day surface to be coded is estimated as follows: // (0 广 ⑴ = Λ ^ est-ACR {1-1) Among them, "(/) is the total activity of the day surface · P (2),-: 4C /? (:! _ 1: I is the ratio of the activity amount to complexity of the previously coded day surface of the same type. Below, The superscript (i) in a symbol or variable indicates that the symbol or variable is related to the current day surface to be encoded; similarly, the superscript in a symbol or variable is related to the previously coded day surface. Estimated complexity It can be used to update the complexity of the appropriate type of diurnal surface, so the complexity of the three types of diurnal surfaces q, Cp, and CB will be stored separately

0702-740.0TWf (Nl); 90P113; Lm.ptd page 13 200428880 V. Description of the invention (9) To facilitate subsequent processing. The instantaneous complexity of a group of continuous pictures is also updated in the following way: INST_C = Nj x + Np x Cp + N3 x C5 where Ni, NP, and NB are I-, P- And B-the number of diurnal planes, and the set of consecutive pictures referred to here contains at least one set of GOPs. Once the instantaneous complexity ^ ST_C has been determined, the target bit quota of the current day-time household] is TB (Β ρ · ⑴ ——- xR ^ INST C ', where Reii is a set of effective day-time effective bits The amount of usage. According to the above formula, the target bit quota is directly proportional to the complexity and inversely proportional to the instantaneous complexity JJVST_C. All MPEG-2 data bit streams must follow the MPEG-2 standard video buffer checker (V ide ο Buffer Verifier, VBV) rule, the allocated target quota must be limited so that the VBV buffer will not overflow (overf 10w) or be scarce (underf 1 ow). It was originally only available after encoding. The current average quantization level of the daytime plane can be estimated after the target bit quota is determined. According to the present invention, the current average quantization level of the current daytime plane Pα] is as follows: = ___ XB ^ xACR ^ where 2 are taken as The initial value of the average quantization level.

III 0702-7400TWf (Nl); 90P113; Lin.ptd Page 14 200428880 V. Description of the invention (10) Under the initial value of the quantization level, the video code is crying.), Output better daylight quality. ^ After checking the determined bit quota and the initial value of the quantization level, you can use the target location. Image encoder, such as described by the MPEG-2 standard = many different types of

Model 5), according to the target bit quota; ^ Type 5 (Test is currently completed after the coding, i ;: of; contraction. ^ The complexity of 1 will be available, and The relationship between the amount of activity and the actual complexity can be obtained from the following calculations,

AQ (i) X

ACR;: U is directly proportional to the full activity 'and is inversely proportional to the actual number of consumed frames UB (o and the average quantizer (0, not eighty w & white dagger). This can be used to estimate the next picture by hand The complexity of the diurnal surface of the same type. ^ Jealousy] ACT [2-1] makes a linear combination to avoid being affected by the richness 17 Too respectful from the mouth w 丨 Yitian 3 is also affected by the diurnal surface. Ben 1 The video coding of the early person of the month (31 called 161 & 33) can be explained by the preferred embodiment and the operation flow chart of Fig. 4. If the day is 3 = No, the moving image video encoder 30 includes a motion estimation. Unit 3: two complexity estimators 3 2 0, a quota dispatcher 3 3 0,-:-quantization level estimation surface and an image coding "more than two sets of continuous day planes in the video sequence will soon be encoded. Then, the surface π is used to perform the current activity of the daytime surface when performing block matching of the motion estimation (step S410). Based on the full activity volume: and the previous encoding of the same type in this set of continuous daylight surfaces Screen its, complex

200428880 V. Description of the invention (11) The complexity estimator 3 2 0 can be used to estimate the complexity of the current day (step S42). The quota dispatcher 3 30 updates the continuous day and time of this group with the estimated complexity. Instantaneous complexity / hysteresis, c, ϋc% and 0 allocate target bit quota to the current picture # (step S4 30). It is used to encode the initial value of the average quantization level of the current diurnal plane. "The quantization level estimator 35 is determined on the basis of the full activity amount, the target bit quota, and the activity amount (step S440). In this embodiment, Like the encoder 3 6 0 based on the initial value, adaptively quantify the current day betting, and after completion, return the actual number of bits consumed (0 and the average quantization level but 0 (0 to the parameter updater 34 0). (Step S45 0). Based on the full activity amount, the actual number of consumed bits, and the actual average quantization level, pan 0, the parameter updater 340 calculates the amount of activity versus complexity for the current day (乂 cf) (step S 460). 3 Wait, above, the preferred embodiment of FIG. 3 can be implemented by hardware and / or software. According to the present invention, the mobile estimation unit 3 and 0 Other components can be operated in pipeline mode. Before the second device 3 2 0 starts to calculate the current complexity of the day, move estimates, sigh, people: You must first complete the full activity of the current day that will be coded. Erzao—Estimate of the 3 10 moving vector, and When the mobile estimation unit calculates and prepares for 3 mile, the complexity estimator 3 2 0 and other components are still working under the current day surface. The next step will be completed in detail— Each element in the example.

200428880

1. One of the main purposes of the motion estimation unit 310 is to decide what prediction mode to use to encode each M β in a daytime plane. If necessary, it also performs forward uranium and backward motion prediction. Extracting information from written / tongue movements during matching operations. First, calculate the amount of activity of each MB (丨 nt η — activUy), and set the pixel intensity of 4 of 8 in a block with a luminance value as Ym, n'm-0, ..., 7, η = 0, ..., 7, and the average value of each 8x8 block? , Then the amount of activity within each MB IntraAct ·· 3

MroAct = k == 〇 Where V ?? ϊ = 0? 2 = 43 If a lower computational complexity is required, the relative absolute difference can be substituted: 3

IntrcL ^ ct = where ^ -ςςK, --ψ 7? Ί = 0? 2 = 0 Because MB in I-day has only one mode ... I mode, so IntraAct is every MB of I-picture Of activity. If the daytime picture is a P- or B-picture, then motion estimation is required. Most often

200428880 V. Description of the Invention (13) The technique used to find the best motion vector is block matching. For non in tra coding (such as P- and B-day), choose to use forward, backward, or bidirectional prediction or No motion compensation is required. Once the MB mode of each MB in the P- or B-day is determined, the variation number of 4 8 × 8 blocks in the difference Mβ of each motion compensation can also be obtained. The difference MB of the motion compensation is pending. The pixel-to-pixel difference between the estimated and MB; the absolute value of distortion and usually have better computational efficiency 'so it can be used to replace the k-different. Add the sum of the absolute values of the variations or distortions of the four 8 X 8 blocks to obtain the inter-activity of each MB in the non-encoded diurnal surface. The IntraAct and InterAct of each MB are compared to determine whether the InterAct is smaller. If it is, then the interAct is used as the Mβ activity amount, and the MB is coded in inter-mode; otherwise, the IntraAct is used as the The amount of MB activity and encodes the MB in intra mode. Finally, for the current: [―, p—, or ^ diurnal surface, add all the activity amounts of ㈣ to get the full activity amount, and the motion estimation unit 310 then sends the full activity amount, # to the complexity estimator 2 0, parameter updater 34 0 and quantization level estimator 3 5 0. Next, the 'complexity estimator 3 2 0 is the current diurnal plane of a certain type.] Estimating the complexity of i / and according to the three diurnal types, introduce a weighting coefficient to the estimation: complexity β. Since it is impossible to estimate the other day planes with the B-day plane, the weighting coefficient of the B-day plane can be reduced to allocate fewer bits to the ^ -day plane while retaining more bits to I- and P- Picture; in general, encoding a picture will produce

0702-7400TWf (Nl); 90P113; Lin.ptd Page 18 200428880 V. Description of the invention (14) The most bits, so the weighting coefficient of P-day is smaller than the weighting coefficient of I-picture. The complexity estimator 3 2 0 updates the complexity q, CP, or CB based on the current type of the daytime surface to estimate one of three ways: ί / (ΐ-picture) e / m / (P-daytime) else z / ( B-picture) 乂 1 0) ACR \ .4 'At present, the complexity of the daytime surface is as follows -1; (0

ACR

0-D 乂 | (0 ACR (rl) where Hf-1; 4〇 Qiu ~ and a series of successive day-planes, each of the previously coded day-planes of the I, p, and B types have their respective activity to complexity These nf 〃, 乂, and up are stored in the parameter updater 3 4 0, and the complexity estimator 3 2 0 will read the corresponding amount of activity to the complexity of the previous diurnal surface of the appropriate type. L , KP, and KB are the weighting coefficients of I-, P-, and B-days, respectively, and their ranges are generally between 0 and 1.0. As for I-days, the preferred embodiment can use 1.0. When received At this time, the quota dispatcher 3 3 0 continuously updates the group daily.

0702-7400TWf (Nl); 90P113; Lm.ptd Page 19 200428880 V. Description of the invention (15) Its instantaneous complexity is quickly cut to 20 and the target bit quota is allocated to the current daytime Pco. The instantaneous complexity is "ST- The update of C is as follows:

S ^ T_C = NT xCj + Np X Cp + Nb X CB where%, NP, and Nβ are the numbers of I-, P-, and B- diurnal planes in the continuous diurnal plane of this group, respectively. In addition, the current target bit quota of the day: Γ5 (2) is TB (lJ = —— ^ — X —xi? II'IST ^ C f, where n is the number of consecutive day and day in this group, f Is the number of diurnal planes per second, that is: the frame rate (fr am erate). R is the expected average bit rate of each group of continuous diurnal planes. However, the actual number of consumed bits does not match the expected bit rate. The quotas are just equal, so develop a feedback strategy to make the number of bits actually consumed by the picture close to the target quota. In a preferred embodiment, the amount of super-used bits encoded to date can be calculated from the current day being encoded. Part of the noodles:

TB {0 = TB (i) -ARxEB Among them, the EB is the overused bit amount transmitted by the parameter updater 3 4 0, and AR is the predetermined amortization rate, and its range is generally from 0.5 to 0. Between 2. The quota dispatcher 3 3 0 must adjust the target bit quota to comply with the VBV specification, so it also sets the upper limit (ϋ —bound) and lower limit (L_bund) of the quota. For constant bitrate'CBR operations, the target bit quota allocated to a daytime plane must be such that the VBV buffer will not overflow or be scarce, so the target bit quota is strongly limited to Within the lower limit:

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V. Description of the invention (16) if (Γ3ω > u —bound) then ⑴ = U —bound if (< L —bound) then tb (i) = L_bound if it is a variable bit rate (v ar i ab 1 ebitrate, VBR) operation, you can prevent VBV scarcity, so: ^ if (rs [2) > u —bound) then S0.) Two U —bound Then, the target bit quota rs⑴ Will be transmitted to the parameter updater 3 4 0, the quantization level estimator 3 5 0, and the image encoder 3 6 0. Once the target bit quota to⑴ is determined, the quantization level estimator 350 can estimate the initial initial value of the average quantization level ⑶ required for its encoding for the current day plane p (o. It is used to quantify a specific type of current day plane p (2) The initial value is estimated as follows: = 乂 ⑺ — T ^ xACR ^ · ^ e / wi / (P-picture)

T ^ xACR ^^ p // (B-picture)

0702-7400TWf (Nl); 90P113; Lin.ptd page 21 200428880 V. Description of the invention (17) First, one T ^^ xACR (i ~ ^

B then passes the initial value of the average quantization level to the image encoder 36. By adaptively changing the quantization level of each spatial region in the daylight, the video encoder 300 of this embodiment uses a virtual buffer (virtual buffer) to provide a bit rate controlled feedback mechanism. Virtual buffers and adaptive quantification are familiar to those skilled in the art, so they will not be repeated here. The utilization status of the virtual buffer (OCC UP ancy) controls the quantization level, thereby controlling the bit rate. However, the virtual buffer must specify an initial utilization status before it can operate, and the utilization status of the virtual buffer also reflects In order to encode the quantization level of the mother-spatial region, the utilization of the virtual buffer not only controls the initial value of the quantization level, but also controls the visual quality under the condition of giving a localization rate. With the help of the initial values, the image encoder 360 can make the quality of the day and night in the video sequence more consistent. Through the signal line 312, the image is coded 3 to 60 to receive the picture data from the motion estimation unit 31, as well as the amount of movement and the MB mode of each handsome. In order to reduce the amount of visible distortion in the case of locating the amount of positioning elements, the image encoder 3 60 determines the quantization level of each side of the current day and day based on the average quantization level. &Amp; Based on the data, the image encoder 360 starts to enter the current day and time] :: and outputs the encoded data CD. After the current day-day betting coding, Guangzhou, Bianmao Zhai averages the quantization levels and calculates the actual number of bits consumed), and then returns the current day-time jealousy] and the average quantization level offender (0 to come

200428880 V. Description of the invention (18) Number updater 340. The target bit quota ra (2) of the day surface P (z) and the actual number of bits you consume (the gap of 〇 will be accumulated by the parameter updater 34 0 so that the day horse surface) will get the super-used bit Elementary EB: ^ < EB-EB X (1-) + UB (i)-TB (i) where AR is the predetermined rate of return. Therefore, the relationship between the amount of activity and the actual complex sound is awkward. From the following calculation, ACR ^ =-^ pr, 4gu) X UB (2) can be used to estimate the complexity of the next diurnal surface of the same type. In order that 乂 Ci? (2) will not be enriched The effect of noise day and day, the preferred embodiment uses a linear combination of 乂 CR: (2-1), for example: ί / (Ι_Picture) ACR (ji) = ACR (/ a) x (l-CW ) ~ l · ACR (0 x CIV else i / (P-picture) ACR (;) = ACR ^ a) x (l-CW) + ACR1'0 x CW else i / (B-picture)

ACR (^) = ACR (J ~ l) x (l-CIV) + ACR (i) x CW where CW is a predetermined weighting coefficient for the linear combination. The updated ACRf; and 〃 are transmitted to the complexity estimate Device 3 2 0 and quantization level 200428880 V. Description of the invention (19) The device 3 50 is used to estimate the initial value of the complexity and the quantization level for the next appropriate type of screen. In addition, the bit amount EB is overused. Then it is sent to the quota dispatcher 3 3 0 for bit allocation. Although the present invention has been disclosed as above with a specific embodiment, it is only for easy explanation of the technical content of the present invention, and is not limited to the present invention in a narrow sense. In the embodiment, anyone skilled in the art can make some modifications and retouching without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.

0702-7400TWf (Nl); 90P113; Lm.ptd Page 24 200428880 Brief description of the diagram Figure 1 shows a typical daytime group (GO P) in the order shown; Figure 2 is a large block of M PEG FIG. 3 is a block diagram of a bit rate control device according to a preferred embodiment of the present invention, and FIG. 4 is an operation flowchart of the present invention. Symbol description 3 0 0 ~ Motion video encoder; 3 1 0 ~ Motion estimation unit; 3 1 2 ~ Signal line; 3 2 0 ~ Complexity estimator; 3 3 0 ~ Quota dispatcher; 3 4 0 ~ Parameter update 3 0 0 ~ quantization level estimator; 3 6 0 ~ image encoder; ⑴ ~ day surface; 乂 (2) ~ full activity; Qiao ~ estimated complexity; ~ ratio of activity to complexity; ΕΒ ~ Over-used bit amount; ~ Target bit amount; ~ Average quantization level; ~ Actual number of bits consumed;

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0702-7400TWf (Nl); 90P113; Lm.ptd page 26

Claims (1)

200428880 6. Scope of Patent Application 1. A method for controlling bit rate of dynamic image compression using initial quantization level estimation, including at least the following steps: Calculating a full activity amount for a current day surface to be encoded, the current day surface In a set of continuous diurnal planes of a video sequence; based on the ratio of the amount of activity to the complexity of the previously coded diurnal planes of the same type of continuous diurnal planes in the current diurnal plane, estimate the One of the current day-to-day complexity; update the instantaneous complexity of the set of consecutive day-to-day surfaces with the estimated complexity of the current day-to-day; assign a target bit quota to the based on the estimated complexity and the instantaneous complexity Current day; based on the total activity of the current day, the target bit quota of the current day, and the ratio of the amount of activity to the complexity of the previously coded day of the same type, a decision is made to encode the current day An initial value of the average quantization level of one of the diurnal planes; encoding the current diurnal plane in the video sequence according to the initial value of the average quantization level; and encoding the current diurnal plane After that, the ratio of the current day's activity to the complexity is calculated based on the full activity of the current day, the actual number of bits consumed by the current day, and the average quantization level of the current day. The ratio of the activity amount to the complexity of the current day surface is directly proportional to the total activity amount of the current day surface, and is inversely proportional to the actual number of bits consumed by the current picture and the average quantization level of the current day surface. 2. Bit rate of video compression as described in item 1 of the scope of patent application 0702-7400TWf (Nl); 90P113; Lm.ptd Page 27 200428880 6. The method for controlling the scope of the patent application, including at least the following steps: Perform the above-mentioned current day-to-day activity ratio to complexity ratio and the previous type of the previous type A linear combination of the ratio of the activity to the complexity of the coded day surface. 3. The bit rate control method for moving image compression as described in item 1 of the scope of patent application, wherein the above-mentioned full activity amount for calculating the current daytime surface is when the current daytime surface is subjected to motion estimation. 4. The bit rate control method for moving image compression as described in item 1 of the scope of patent application, wherein the above step of estimating the complexity is calculated according to a formula: like ACR, where Cest is the above-mentioned complexity of the current day-time estimation Degree, K is a predetermined weighted value, ranging from 0 to 1, A is the above-mentioned full activity of the current day in the above-mentioned group of continuous day, and ACR is the previously coded day of the same type The ratio of its activity to complexity. 5. The bit rate control method for moving image compression as described in item 1 of the scope of patent application, wherein the allocated target bit quota is directly proportional to the above-mentioned complexity of the current day surface, and is related to the above-mentioned group of continuous day surfaces The above-mentioned instantaneous complexity is inversely proportional. 6. The bit rate control method for moving image compression according to item 1 of the scope of patent application, wherein the initial value of the average quantization level is determined by the following function: 0702-7400TWf (Nl); 90P113; Lm.ptd Page 28 200428880 6. Patent application scope x TBxACR, where MQest represents the initial value of the above average quantization level, and A is the above-mentioned current day-plane in the above-mentioned group of continuous day-planes For full activity, TB is the above-mentioned target bit quota for the current day and above, and ACR is the ratio of its activity to complexity for the previously coded day of the same type. 7. The bit rate control method for dynamic image compression according to item 1 of the scope of the patent application, wherein the above-mentioned group of continuous day-planes includes at least one group of pictures (G0P), and the day-plane groups conform to MPEG video standard. 8. — A dynamic image compression bit rate control device using initial quantization level estimation, including at least: a motion estimation unit that receives a current day surface that is about to be encoded in a group of continuous day surfaces in a video sequence, and uses Comes to calculate the full activity of one of the current diurnal planes when performing block matching of the motion estimation; a complexity estimator based on the full active amount of the current diurnal planes and the previous type of the same group of consecutive diurnal planes Encodes the ratio of the amount of activity to the complexity of the diurnal surface to estimate the complexity of the current diurnal surface; a quota dispatcher that updates the instantaneous complexity of one set of consecutive diurnal surfaces with the complexity estimated by the current diurnal surface Degree, used to allocate a target bit quota to the current day plane based on the estimated complexity and the instantaneous complexity; a quantized rank estimator, based on the full activity of the current day plane, the current day plane Based on the target bit quota and the activity-to-complexity ratio of the previously encoded picture of the same type, the decision is made to encode the current day 0702-7400TWf (Nl); 90P113; Lm.ptd page 29 200428880 VI. One of the scope of patent application average initial quantization level initial value; and a parameter updater, based on the current activity of the current day surface, the current day surface Based on the actual number of consumed bits and the average quantization level of the current day, calculate the ratio of the current day's activity to the complexity; where the ratio of the current day's activity to the complexity and the current day The total amount of activity on the diurnal surface is directly proportional to the number of bits consumed by the current diurnal surface and inversely proportional to the average quantization level of the current diurnal surface. 9. The dynamic image compression bit rate control device according to item 8 of the scope of the patent application, wherein the parameter updater also executes the ratio of the current day's daytime activity to the complexity and the previously coded daytime surface of the same type. A linear combination of the ratio of activity to complexity to reduce noise. 10. The dynamic image compression bit rate control device described in item 8 of the scope of the patent application, further comprising at least one image encoder, which encodes the current day surface according to the initial value of the average quantization level, and The actual number of bits consumed by the diurnal plane and the average quantization level used by the current diurnal coding are reported to the parameter updater. 11. The bit rate control device for moving image compression as described in item 8 of the scope of patent application, wherein the above-mentioned complexity of the current daytime surface estimated by the above-mentioned complexity estimator is based on a formula: like ACR, Cest is the above-mentioned complexity of the current day-to-day estimates, and K is an established 0702-7400TWf (Nl); 90P113; Lm.ptd Page 30 200428880 VI. The weighted value of the patent application range, which ranges from 0 to 1, A is the above-mentioned current day-plane in the above-mentioned group of continuous day-planes Full activity, ACR is the ratio of the activity to complexity of the previously coded diurnal surface of the same type. 12. The bit-rate control device for moving image compression as described in item 8 of the scope of the patent application, wherein the allocated target bit quota is proportional to the above-mentioned complexity of the current day surface and is proportional to the above-mentioned group of consecutive day The above-mentioned instantaneous complexity is inversely proportional. 13. The dynamic image compression bit rate control device according to item 8 of the scope of the patent application, wherein the quantization level estimator determines the initial value of the average quantization level with the following function: wherein MQest represents the initial value of the average quantization level, A is the above-mentioned full activity of the above-mentioned current day-plane in the above-mentioned group of continuous day-planes, TB is the above-mentioned target bit quota of the above-mentioned current day-plane, and ACR is the previously-encoded day-plane of the same type Activity to complexity ratio. 14. The dynamic image compression bit rate control device according to item 8 of the scope of the patent application, wherein the above-mentioned group of continuous daylight planes includes at least a daylight plane group (GOP), and the daylight plane group Compliant with MPEG video standards. 0702-7400TWf (Nl); 90P113; Lin.ptd page 31