CN1133324C

CN1133324C - Captions superposing method

Info

Publication number: CN1133324C
Application number: CN 99111318
Authority: CN
Inventors: 黄天; 张明; 朱雄羽
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 1999-08-05
Filing date: 1999-08-05
Publication date: 2003-12-31
Anticipated expiration: 2019-08-05
Also published as: CN1283931A

Abstract

The present invention discloses a caption superposition method, which is applied to a system of a conference TV. The present invention is characterized in that the method at least contains the following steps that the contents of captions to be superposed are superposed with images before the images at the transmission end are encoded, and the superposed captions and the images are encoded. Then, the captions and the images are transmitted to the terminal of the receiving end, are decoded and displayed. The present invention solves the defects of the superposed captions of a caption card in the application of the conference TV, leads any terminal of the conference TV to be flexibly and conveniently superposed onto pictures. Then, the captions are transmitted to the receiving end of a far end to be decoded and displayed.

Description

A kind of stacking method of captions

Technical field

The present invention relates to video pre-process and post-process technical field, be specifically related to be applied to the stacking method of a kind of captions in the video conferencing.

Background technology

In the application of video conferencing, the subtitle superposition technology is a kind of very useful technology.In the process that meeting is carried out, often need pass through the mode of broadcast subtitle and point out some information relevant with meeting.Show that its meeting-place name is necessary as each meeting-place in session, which meeting-place what can allow the participant be clear that like this to show on the screen is.In addition in session in, making each terminal can both broadcast some information also is of great use.

Normally used subtitle superposition technology is to adopt the mode of a title insert to realize.The mode of this title insert overlapping text is before video shows subtitle superposition to be gone to image, that is to say, each terminal is just subtitle superposition to be got on after receiving the image that far-end sends here.H.261 or coding standard H.263 the ITU.T that the Code And Decode process of TV conference system image is followed International Telecommunication Association.When carrying out subtitle superposition, at first import the caption content that will show from the receiving terminal backstage, again this caption content is converted to the caption image of public intermediate-resolution pixel format (CIF) or extended formatting (for example dot matrix format), then with the stack of the pictorial data of CIF form (the stack computational methods of two CIF images can referring to International Telecommunication Association H.261 or coding standard H.263), form the CIF format pattern data of band captions.

The shortcoming of prior art is, what receiving terminal showed is the remote site image, and the captions that need stack also are and the corresponding meeting-place explanation of this remote site information such as (for example meeting place names), in this case, caption content input and image overlay step are arranged on receiving terminal, just be easy to lead to errors or inharmonious, for example when showing the meeting-place name, what the operating personnel of receiving terminal needed to know present demonstration in advance in allocation list is that remote site, could get on the meeting-place name displayed image that is added to.In case it is wrong that this mode allocation list upgrades, perhaps allocation list can not upgrade in time, all will cause the meeting-place name to show mistake.Another shortcoming of prior art is that in this manner, each meeting-place can only send pictorial information or control information to other-end, and can't send caption information, has limited the application of video conferencing.

Summary of the invention

In view of this, a kind of purpose of the present invention just is to provide a kind of stacking method of captions, to solve the deficiency of title insert overlapping text in video conferencing is used, make TV conference system can be more flexibly, overlapping text easily.

For achieving the above object, technical scheme of the present invention specifically is achieved in that

A kind of stacking method of captions is applied in the system of video conferencing, and the method includes the steps of:

The caption content that superposes superposeed with image before the image encoding of transmitting terminal; Captions after the stack are encoded with image, and the terminal that re-sends to receiving terminal is carried out decoding and displaying.

Described stack can may further comprise the steps:

A) from sending the caption content of terminal input desire stack;

B) this caption content is written in the middle buffer memory that sends terminal;

C) a captions buffer area that will this centre data in buffer writes transmitting terminal image processing template;

D) carry out supercomposed coding with the view data that sends.

Captions buffer memory in the described step c) adopts the first in first out buffer memory, and writing can be that mode by block operations realizes.

Writing of described step b) can comprise: if the caption content of desiring to write has converted public intermediate-resolution pixel format coded format to, then only need write this centre buffer memory in proper order; If the caption content of desiring to write is for by the latticed form of row format, then the address that will calculate the picture element in each dot matrix according to public intermediate-resolution pixel format coded format writes corresponding address then.

Before the described step a) or after the step a), can may further comprise the steps before the step b),

One captions controlled flag is set and is changed to effectively this buffer zone, centre of initialization; And

After the described step c), it is invalid putting this captions controlled flag.

In the stacking method technical scheme of a kind of captions of the present invention, the captions that superpose superposeed before picture coding, and captions are delivered to each meeting-place terminal again and gone decoding and displaying after image is encoded.Caption content can be passed through terminal backstage, stackable captions whenever and wherever possible.The resolution of captions is CIF (352 * 288), and Y/C (brightness/chroma) is all 8bit.The captions buffer memory adopts first-in first-out (FIFO) buffer memory, and FIFO does not have the notion of address, can only take the mode that refreshes entirely, is raising speed, the mode of buffer memory in the middle of adopting.FIFO does not have the notion of address, therefore can save address resource.

After adopting technical solution of the present invention, any one terminal of video conferencing, as long as apply to become chairman, all easily overlapping text to picture, captions can be delivered to distal displayed easily with picture, to solve the deficiency of title insert overlapping text in video conferencing is used, make TV conference system can be more flexibly, overlapping text easily.In addition, in this manner, each meeting-place can realize that the information that will send superposes whenever and wherever possible, to be broadcast to other terminal.Because the method for this overlapping text is digital-to-analogue conversion (AD) part of handling in the video front and back end, therefore this subtitle superposition mode is also referred to as the AD captions.

Description of drawings

Fig. 1 is the subtitle superposition process schematic diagram before the image encoding of the present invention.

Fig. 2 is the stack schematic flow sheet of the embodiment of the invention.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, below in conjunction with embodiment and accompanying drawing, the present invention is described in more detail.

At first, see also shown in Figure 1ly, caption content is after terminal background interface input, to be put into earlier in the middle buffer memory on terminal foreground, for example, one section region of memory 0x700000～0x73FFFF of PC is as the middle buffer memory of AD captions, and earlier this section zone is initialized as 0xFF.Here, the input of terminal background interface can be keyboard input, or the input of alternate manner such as touch-screen.

When caption content is write the middle buffer memory of this section region of memory,, corresponding Y or C value are write high-end (buffer memory in the middle of this part of 7M～8M) as long as calculate the side-play amount that corresponding address (through the CIF format conversion) adds 7M.

After all having write, utilize piece to move again, middle data in buffer is write among the AD subtitle region address FIFO that 0x840000 begins on the image processing plate ADA plate.The captions of depositing among the FIFO, and are seen coding off and are sent in image with regard to stackable.

It is as follows to see also detailed process shown in Figure 2, above-mentioned:

(1) captions controlled flag register is set, and it is changed to 0.

(2) zone of the 256byte of region of memory 0x700000～0x73FFFF is warded off be middle buffer memory, and be initialized as 0xFF.

(3), then only need write in proper order in the top middle buffer memory if the caption content that will write has converted the CIF form to.If press the latticed form of row format, then to calculate the address of the picture element in each dot matrix according to the CIF form, write appropriate address then.

(4) after Shang Mian process is finished, zero clearing captions buffer memory write pointer.The captions buffer memory that the content block copy of middle buffer memory is begun to the 0x840000 of image processing plate then.

(5) this caption data and view data are carried out supercomposed coding.

(6) writing captions controlled flag register is 1.

Caption superposition method in a kind of TV conference system of the present invention superposeed the captions that will superpose to get on before picture coding, and captions are delivered to each meeting-place terminal again and gone decoding and displaying after image is encoded.Make that the subtitle superposition of TV conference system is more flexible, and the caption information that each meeting-place can will send superposes whenever and wherever possible, to be broadcast to other terminal.

Claims

1, a kind of stacking method of captions is applied to it is characterized in that the method includes the steps of in the system of video conferencing:

2, the stacking method of captions according to claim 1 is characterized in that described stack may further comprise the steps:

A) from sending the caption content of terminal input desire stack;

D) carry out supercomposed coding with the view data that sends.

3, the stacking method of captions according to claim 2 is characterized in that: captions buffer memory in the described step c) adopts the first in first out buffer memory, and writing is that mode by block operations realizes.

4, the stacking method of captions according to claim 2 is characterized in that writing of described step b) comprises: if the caption content of desiring to write has converted public intermediate-resolution pixel format coded format to, then only need write this centre buffer memory in proper order; If the caption content of desiring to write is for by the latticed form of row format, then the address that will calculate the picture element in each dot matrix according to public intermediate-resolution pixel format coded format writes corresponding address then.

5, the stacking method of captions according to claim 2 is characterized in that: before the described step a) or after the step a), may further comprise the steps before the step b),