Moving image reproduction method and moving image reproduction system
A moving image reproduction method includes: dividing data of each of plural frames of a moving image to be displayed on a client terminal using a browser into blocks; judging whether each of the blocks has same information in the preceding frame; obtaining compressed data by encoding each block for which the preceding frame does not have the same information by a method compatible with a still image decoder; preparing compressed still image data in which the compressed data are arranged in succession; describing, for each block, information indicating presence/absence of the same information into image restoration information; preparing image restoration compressed information by encoding the image restoration information; and preparing a display program which is written in a description language that can be interpreted by the browser for reconstructing the data of moving image.
1. A moving image reproduction system comprising:
a client terminal that is provided with a browser; and
a web server that is connected to the client terminal via a network,
wherein the web server stores compressed still image data formed JPEG and image restoration information formed base 64 format or as PNG image data in separate files, the compressed still image data and the image restoration information being prepared by the web server, the image restoration information being information referred to by the browser to reconstruct a moving image from the still image data, and the web server being configured to perform a process comprising:
dividing data of each of plural frames of a moving image to be displayed on the browser of the client terminal into macro blocks;
determining whether each of the macro blocks has same information as in a preceding frame;
encoding, with JPEG format that is decodable with a still image decoder incorporated in the browser of the client terminal, image data of each macro block for which the preceding frame does not have the same information to generate compressed still image data;
generating first reference information with respect to the macro blocks that do not have the same information that is in the preceding frame;
generating second reference information with respect to the macro blocks deemed to have the same information that is in the preceding frame, the second reference information including a motion vector;
generating the image restoration information including the first reference information and the second reference information formed base 64 format or as PNG image data, the image restoration information not employing interframe differential compression processing; and
providing the image restoration information formed base 64 format or as PNG image data to the client terminal; and
providing the compressed still image data in JPEG format to the client terminal separate from the image restoration information,
wherein the client terminal is configured to perform, based on a JavaScript program, a process comprising:
obtaining the first reference information and the second reference information from the image restoration information formed base 64 format or as PNG image data;
decoding the compressed still image data in JPEG format with a still image decoder incorporated into the browser after the obtaining of the first reference information and the second reference information;
obtaining image data with respect to each macro block associated with the first reference information in the image restoration information;
using, by the browser, image data from a received frame based on the motion vector for each macro block associated with the second reference information in the image restoration information; and
reconstructing by the browser the moving image formed by the plural frames.
2. The moving image reproduction system according to claim 1 , wherein
in judging whether the preceding frame has the same information, a range formed of n ×n macro blocks being a range for the judgment as to presence/absence of same information is reduced by decreasing k where n indicates 2 k and k indicates an integer that is larger than or equal to 1.
3. The moving image reproduction system according to claim 1 , wherein
the browser interprets a description language based on HTML5.
4. The moving image reproduction system according to claim 1 , wherein
an area displaying the moving image at the client terminal is an image drawing area defined by a “canvas” tag of HTML5.
5. The moving image reproduction system according to claim 1 , wherein
the compressed still image data is generated as a plurality of divided compressed still image data in accordance with a still image handling capacity of the client terminal.
6. The moving image reproduction system according to claim 1 , wherein
transparency information compressed information is generated by encoding information relating to transparency of the moving image as an alpha channel, and
the moving image is reconstructed from the compressed still image data by decoding the transparency information compressed information and by incorporating the information relating to transparency.
7. The moving image reproduction system according to claim 1 , wherein the obtaining of the first reference information and the second reference information from the image restoration information comprises decoding the image restoration information formed base 64 format or as PNG image data.