JP2002016912A - Video encoding device - Google Patents

Abstract

(57) [Problem] To realize a moving picture coding apparatus using a two-pass coding system with a configuration using only one encoder, and to reduce the scale of the apparatus. A preceding data generation unit creates a reduced image with a reduced resolution from an input image signal, and stores the reduced image in a preceding data memory. After the delay memory 3 delays the time by generating the reduced image from the input image signal and storing the reduced image in the preceding data memory, the multiplexing unit 13 outputs the reduced image output from the preceding data, The image signal output from the delay memory is multiplexed within one picture time. Further, the single encoder 13 encodes the multiplexed reduced image and image signal, and the demultiplexer 14 encodes the encoder 13
The reduced image portion is separated / deleted from the encoding result according to (1) and is output as encoded data 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving picture encoding apparatus for encoding moving pictures with high efficiency and digitally transmitting them.

[0002]

2. Description of the Related Art In a moving picture coding apparatus for compressing and transmitting moving pictures by using a high efficiency coding technique, in order to control the amount of data after compression with high accuracy or to control the quality of the compressed picture. For the purpose of keeping higher, etc., first, the moving image is preliminarily compression-encoded and the amount of data after compression and statistical data indicating the characteristics of the image are estimated (first pass),
Next, a method of performing compression encoding by adjusting the encoding parameter based on the estimated data amount or statistical data (second pass) may be adopted. Hereinafter, such a method is referred to as a two-pass encoding method. A moving image encoding apparatus using a two-pass encoding method is known, for example, from Japanese Patent Application Laid-Open No. H11-98502. The moving picture coding apparatus disclosed in Japanese Patent Application Laid-Open No. 11-98502 will be described with reference to FIG. In FIG. 5, 1 is an input image signal, 2 is an encoder A for performing first pass encoding, 3 is a delay memory, 4 is an encoder B for performing second pass encoding, and 5 is an encoder A coding control unit 6 for controlling A 2 and the encoder B 4 is coded data.

Next, the operation of the conventional moving picture coding apparatus shown in FIG. 5 will be described. First, the input image signal 1 is input to an encoder A2 that performs first-pass encoding, and performs first-pass encoding. At this time, the encoding control unit 5
In addition to controlling the encoder A2, the amount of encoded data obtained when the encoder A2 performs the first pass of encoding, the motion vector, the frequency distribution, and the difference between the previous picture and the current picture Statistical data such as absolute values are stored. On the other hand, the delay memory 3 is
The input image signal 1 is delayed by the time spent for the first pass encoding. Thereby, the encoding control unit 5 stores all the encoded data amount and statistical data obtained by the encoding in the first pass, and then encodes the data in the second pass by the encoder B4. Can be performed. that time,
The encoding control unit 5 adjusts the encoded data amount obtained by the first-pass encoding and the encoding parameter based on the statistical data to thereby reduce the encoded data amount to a desired value. High image quality can be realized while suppressing the data amount.

[0004]

In the above-described moving picture coding apparatus using the conventional two-pass coding method, an encoder for performing a first-pass coding in order to realize coding in real time. It is necessary to have two encoders having the same configuration, that is, an encoder A and an encoder B that performs second-pass encoding. For this reason, there is a problem that the apparatus scale of the moving picture coding apparatus becomes very large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and realizes a moving picture coding apparatus using a two-pass coding system with a configuration using only one coder. It is intended to reduce the scale of the apparatus.

[0006]

An image encoding apparatus according to the present invention preliminarily compresses and encodes a moving image by using a high-efficiency encoding technique to determine the data amount and properties of the moving image after compression. The first pass encoding for estimating statistical data to be shown is performed, and the second pass encoding for performing compression encoding by adjusting encoding parameters based on the estimated data amount and the statistical data is performed. In the moving picture coding apparatus, a preceding data generation unit that creates a reduced image with a reduced resolution from an input image signal, a preceding data memory that stores the reduced image, and the preceding data generation unit that generates the preceding data from the input signal A delay memory for delaying the time by the time stored in the preceding data memory; a reduced image output from the preceding data; and an image signal output from the delay memory for one picture. A multiplexing unit for multiplexing within a channel time, a single encoder for encoding the multiplexed reduced image and image signal, and separating the reduced image portion from an encoding result by the encoder. A separating unit that outputs the encoded data as encoded data, the preceding data generating unit, the preceding data memory, the delay memory, the multiplexing unit, the encoder, and a control unit that controls the separating unit. The separation unit outputs the separated encoded data of the reduced image portion to the encoding control unit, and the encoding control unit calculates an encoding parameter based on the encoded data of the reduced image portion. Adjusting the encoded data of the reduced image portion created by the preceding data generating unit and statistical data obtained from the preceding data generating unit at the time of encoding the reduced image in a first pass code. Gain from Used as the data, and performs coding of the input signal delayed by the delay element is a second pass encoding on the basis of the data obtained in the first pass coding.

[0007] Further, an image coding apparatus according to the present invention comprises:
Instead of a reduced image created with a lower resolution than the input signal, an image obtained by cutting out a continuous portion of the image from the input signal is used.

[0008] Further, an image coding apparatus according to the present invention comprises:
Instead of a reduced image created by lowering the resolution than the input signal, an image obtained by cutting out a discontinuous portion of the image from the input signal and joining the images is used.

Further, an image coding apparatus according to the present invention comprises:
Instead of a reduced image created with a lower resolution than the input signal, an image having the same resolution as the input signal is used.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Embodiment 1 of the present invention will be described with reference to FIG. FIG.
1 is a configuration diagram of a video encoding device according to Embodiment 1 of the present invention. In FIG. 1, 1 is an input image signal, 3 is a delay memory, 10 is a preceding data generation unit that generates preceding data, 1
1 is a preceding data memory, 12 is a multiplexing unit, 13 is an encoder, 14 is a demultiplexing unit, 5 is an encoding control unit that controls the encoder, and 6 is encoded data.

Next, the operation of the moving picture coding apparatus shown in FIG. 1 will be described. First, the input image signal 1 is input to the delay memory 3 and the preceding data generator 10. The delay memory 3 is
The input image signal 1 is delayed by one picture time.
The image data delayed by the delay memory 3 is hereinafter referred to as delay data. The delay data is sent to the multiplexing unit 12. The preceding data generation unit 10
Generates a reduced image in which the resolution of the input image signal 1 is reduced. The reduced image generated by the preceding data generation unit 10 is hereinafter referred to as preceding data. The preceding data is sent to the multiplexing unit 12 via the preceding data memory 11.

The multiplexing unit 12 time-multiplexes the delayed data and the preceding data and outputs the multiplexed data, as shown in FIG. The data multiplexed by the multiplexing unit 12 is hereinafter referred to as multiplexed data. The multiplexed data is encoded by the encoder 13
Sent to In the configuration of the conventional moving picture coding apparatus, the coder 13 converts one of the delayed data within one picture time.
Although only the operation speed required to encode the picture was necessary, in the configuration of the video encoding apparatus according to the present invention, the encoder 13 operates more frequently than in the configuration of the conventional video encoding apparatus. You need to set the speed faster. That is, it is necessary to have an operation speed enough to encode one picture of the delayed data and one picture of the preceding data within one picture time.

An encoder 13 encodes multiplexed data composed of delayed data and preceding data within one picture time. At this time, motion compensation prediction is performed from the preceding data area when encoding the delayed data, and conversely, motion compensation prediction is performed from the delayed data area when encoding the preceding data. The encoding control unit 5 performs necessary control so that there is no such error. Thereby, the encoder 13 encodes the delayed data and the preceding data as separate data. Further, statistical data and the like obtained at the time of encoding the preceding data are stored in the encoding control unit 5, and the encoding parameters used at the time of encoding the delayed data of the next picture are adjusted based on the statistical data.

The result of the encoding of the multiplexed data by the encoder 13 is separated by the separating unit 14 into a delayed data portion and a preceding data portion. Of these, the delay data portion is output as encoded data 6. The preceding data portion is used by the encoding control unit 5 to measure the data amount after encoding. Here, an encoding parameter used at the time of encoding the delayed data of the next picture is adjusted based on the measured data amount after the encoding of the preceding data.

The encoding control unit 5 may perform the same control as in the delayed data encoding when encoding the preceding data, but instead, the encoding control unit 5 At the time of encoding, special control such as fixing the quantization step or using only intra-encoding may be performed assuming data to be acquired in advance in the first-pass encoding.

As described above, according to the first embodiment, the moving picture coding apparatus using the two-pass coding method
This can be realized with a configuration using only one encoder, and the device scale can be reduced.

Further, in the first embodiment, the preceding data generating section 10 generates a reduced image in which the resolution of the input image signal 1 is reduced. The reduced image is used as the preceding data. In this case, a continuous portion of an image may be cut out. As a result, a moving image encoding device using the two-pass encoding method can be realized with a configuration using only one encoder, and the device scale can be reduced. In FIG. 3, the entire rectangle represents the screen, and the shaded portion represents the cut-out area of the preceding data.

Also, in the first embodiment, the preceding data generating unit 10 generates a reduced image in which the resolution of the input image signal 1 is reduced. The reduced image is used as the preceding data. The operation speed of the device 13 may be increased to about twice the conventional speed, and the same resolution as the delayed data may be used as the preceding data. As a result, a moving image encoding device using the two-pass encoding method can be realized with a configuration using only one encoder, and the device scale can be reduced. In addition, a moving image with higher resolution can be obtained.

Also, in the first embodiment, the preceding data generating section 10 generates a reduced image in which the resolution of the input image signal 1 is reduced. This reduced image is used as the preceding data. As shown in the above, an image obtained by cutting a discontinuous portion of an image may be used. As a result, a moving image encoding device using the two-pass encoding method can be realized with a configuration using only one encoder, and the device scale can be reduced. In FIG. 4, the entire rectangle represents the screen, and the shaded portion represents the cut-out area of the preceding data. However, in this case,
Since the discontinuous portions of the image are connected and used, the preceding data is encoded using only intra-coding without using motion compensation prediction.

[0020]

As described above, according to the first to third aspects of the present invention, a moving picture coding apparatus using a two-pass coding method is realized with a configuration using only one coder. This has the effect that the device scale can be reduced.

According to the fourth aspect of the invention, in addition to the above-mentioned effects, there is an effect that a moving image with higher resolution can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a video encoding device according to Embodiment 1 of the present invention.

FIG. 2 is a time chart illustrating how multiplexing is performed in a multiplexing unit according to Embodiment 1 of the present invention.

FIG. 3 is an example of preceding data generation in a preceding data generation unit according to Embodiment 1 of the present invention.

FIG. 4 is another example of the preceding data generation in the preceding data generating unit according to the first embodiment of the present invention.

FIG. 5 is a configuration example of a moving image encoding device using a conventional two-pass encoding method.

[Explanation of symbols]

 Reference Signs List 1 input image signal 2 encoder A 3 delay memory 4 encoder B 5 encoding control unit 6 encoded data 10 preceding data generation unit 11 preceding data memory 12 multiplexing unit 13 encoder 14 separation unit.

Claims (4)

[Claims] 1. A first-pass encoding for preliminarily compressing and encoding a moving image using a high-efficiency encoding technique and estimating statistical data indicating a data amount and properties of the moving image after compression. Next, in a moving picture coding apparatus for performing a second pass coding for performing compression coding by adjusting a coding parameter based on the estimated data amount and the statistical data and the like, A preceding data generation unit for creating a reduced image with reduced size, a preceding data memory for storing the reduced image, and a delay for delaying the time by generating the preceding data from the input signal and storing it in the preceding data memory. A multiplexing unit that multiplexes a memory, a reduced image output from the preceding data, and an image signal output from the delay memory within one picture time; Only 1 of encoding the reduced image and the image signal has been
One encoder, a separation unit that separates the reduced image portion from the encoding result of the encoder and outputs the encoded data as encoded data, the preceding data generation unit, the preceding data memory, the delay memory, The multiplexing unit, the encoder, and a control unit that controls the separation unit, the separation unit outputs the encoded data of the separated reduced image portion to the encoding control unit, The encoding control unit adjusts an encoding parameter based on the encoded data of the reduced image portion, and the encoder includes the encoded data of the reduced image portion created by the preceding data generation unit, Statistical data obtained from the preceding data generation unit at the time of encoding the reduced image is used as data obtained in the first pass encoding, and second pass encoding is performed based on the data obtained in the first pass encoding. Is a delay Moving image encoding device and performs coding of the input signal delayed by element. 2. The moving image according to claim 1, wherein a continuous portion of the image is cut out from the input signal, instead of the reduced image created by lowering the resolution than the input signal. Encoding device. 3. An image in which discontinuous portions of an image are cut off from the input signal and connected, instead of the reduced image created by lowering the resolution than the input signal. 2. The moving picture encoding device according to 1. 4. The moving picture encoding apparatus according to claim 1, wherein an image having the same resolution as the input signal is used instead of a reduced image created by lowering the resolution than the input signal.