This invention relates in general to the field of interactive television and more particularly to the recording of interactive television contents and even more particularly to the font handling in the field of recording of interactive television contents.
Interactive television (iTV) is becoming more and more popular. An example for interactive television is the Multimedia Home Platform (MHP), which is a digital video broadcasting (DVB) standard intended to combine digital television (DTV) with interactivity and access to the Internet and the World Wide Web. DTV service providers offer a large variety of audio-visual (A/V) television programs and also of applications allowing the interaction of the viewer/user with the TV set and its contents. The applications are broadcast together with the A/V contents and executed in a television set adapted for this task or in a separate set top box (STB).
Similar to today's video recorders for analogue television broadcasts using video tapes for recording broadcast streams, digital video recorders for interactive television are developed using either a harddisk or removable media such as optical discs for storing recorded broadcasts. The digital video recorders for interactive television record both A/V television contents and applications for playback at a later point of time.
Interactive TV applications consist of an application program part being executed and which uses fonts when displaying characters. These fonts can be either resident in a set top box (STB) or downloaded with the application that uses them. The resident fonts in a STB are commonly called default fonts.
When recording iTV broadcast contents, in the case of downloaded fonts (i.e. fonts embedded in the broadcast transport stream), the downloaded font is currently stored along with each application program together with other files needed by the application program for running the application at a later point of time, when playing back the application. In case of Latin alphabets, the size needed for storing the font is relatively small, in the range of less than about 50 Kbytes. However, in the case of certain other alphabets, such as Asian alphabets, e.g. the Chinese alphabet, the font size is significantly larger, e.g. 2 Mbytes.
When recording the applications as mentioned above, the font is recorded together with each application as it is generally not known which fonts are available in the device executing the application, e.g. a STB. Furthermore, it is likely that a broadcaster will use the same downloadable font for multiple applications, e.g. for esthetical reasons generating the same look-and feel of the applications. Thus, when a plurality of applications is recorded, which all use the same font, the font will have to be recorded, i.e. stored, multiple times. This multiple recording of the same downloaded font data occupies a large amount of storage space on the storage media, as the amount of storage space is limited. Therefore a large portion of the storing media is used for fonts, especially when each font has a large size, or when the number of files, i.e. the number of fonts, stored on the storage media is large. It is desirable to keep the amount of space used for applications is as low as possible, in order to be able to record as much iTV content as possible on a storage medium.
U.S. Pat. No. 6,141,002 discloses a system and method for rendering Unicode text in multiple languages on a set-top box (STB). The STB includes a set of default fonts. When the STB receives a broadcast application with a character which is not part of the default fonts, the STB checks the fonts available through the download application and uses the download font instead. The downloaded font is then stored in a separate memory comprising downloaded fonts, so that the currently downloaded font glyph is available in the future. This method has the drawback that, when the A/V content and the application are to be recorded on a removable medium, such as an optical disc, the font has to be recorded on the disc together with the application. This is due to the fact that the recorded removable medium might be played on another recorder than the one on which it was recorded on. This means that even when the STB has the necessary font in a memory, as disclosed by U.S. Pat. No. 6,141,002, the font still has to be stored on the disc, at least if the disc is removable. Furthermore the font information is stored independent of any application, thus generating a memory space problem with an increasing number of fonts to be stored, i.e. a plurality of fonts will be resident in the font download memory which are not needed for any current application. As the download memory is physically limited, the STB runs out of available download memory. Therefore the problem of keeping the amount of space used for applications as low as possible is not solved by the disclosed system and method.
It is an object of the invention to keep the amount of space used for applications as low as possible, in order to be able to record as much iTV content as possible on a storage medium.
A more detailed definition of the terms used in this disclosure is given below for a better understanding.
A set-top box (STB) is a device which enables a television set to receive and decode digital television (DTV) broadcasts with an existing analogue television set. A STB may also allow a television set to become a user interface to the Internet. Sophisticated set-top boxes contain a hard drive for storing recorded television broadcasts, for download software and for other applications provided by a DTV service provider.
A font is a set of printable or displayable text characters in a specific style and size.
A character is a printable symbol having phonetic or pictographic meaning and usually forming part of a word of text, depicting a numeral, or expressing grammatical punctuation. A character can be distinguished from other characters in terms of meaning and sound.
The present invention overcomes the above-identified deficiencies in the art and solves the above problems by providing according to one aspect of the invention, a method of handling fonts in a recorder or a playback-recorder for interactive television, wherein said fonts are stored on a recordable storage medium, such as a recordable DVD. The fonts are part of a downloaded interactive television applications, and the method comprises, in the case of recording interactive television contents, the step of storing the downloaded fonts separate from the application program in a font library on the recordable storage medium. Each font is only stored once on a storage medium. When playing back the application, according to another aspect of the invention, a method comprises the step of indicating which font or fonts of the font library comprising a plurality of fonts on the storage medium are required for playback of said application from said storage medium and subsequently choosing a font for said application and then merging the chosen font with the application program.
According to another aspect of the invention, an apparatus which is used for recording and/or playing back interactive television contents, wherein said apparatus comprises a font handling device. This font handling device is adapted for use in said apparatus. Fonts being part of downloaded interactive television applications are stored on a recordable storage medium. The fonts are stored separate from the application in a font library on said recordable storage medium, and whereby each font is only stored in one copy.
According to yet another aspect of the invention, a computer readable medium is disclosed, which comprises instructions for performing the above method, wherein the computer readable medium contains thereon a computer program for processing by a computer. The computer program comprises a code segment for storing downloaded fonts from interactive television applications on a storage medium, wherein said code segment instructs the computer to store only one copy of different fonts in said font library.
A further aspect of the invention is a storage medium for interactive television comprising a separate font library and a separately stored application module. The storage medium comprises at least two interactive television applications recorded on it. The applications are stored separate from the fonts needed for running said applications. The storage medium further comprises a font library which comprises fonts, whereby the font library does not comprise more than one copy of each of the fonts needed for running all applications stored on the storage medium.
Downloaded fonts are stored separately from applications in a font library on the iTV storage media. Each font is only stored once, even if it is used with multiple applications.
According to a preferred embodiment of the invention, the iTV application is during recording parsed for fonts, which it includes. The fonts are then removed from the application module. If the fonts are already downloaded, i.e. if the fonts are already stored in the font library on the storage medium, preferably a removable medium, the downloaded copy of the fonts is disregarded. In the other case, the downloaded font is stored in the font library on the storage medium. The modified application module without the font is stored on the storage medium.
For playback, an info file indicates which fonts are required for playback of the application. The fonts are loaded from the font library and merged with the application program and the other application files for running the recorded application.
Thus, the invention solves the problem that fonts use an unnecessarily large amount of storage space on a storage medium in the case of multiple iTV applications using the same font.
These and other aspects of the invention will be apparent from and elucidated with reference to the drawings and the embodiments described hereinafter.
A number of exemplary embodiments of the present invention will be described in the following detailed disclosure, reference being made to the accompanying drawings, in which
3A and 11A show schematic diagrams over iTV structures to be recorded,
3B and 11B show schematic diagrams over iTV recordings of the structures from
Generally, an iTV broadcast includes a number of files, some of which are applications, generally consisting of executable code in Java, and some are data files including the above mentioned font files. The application indicates generally the font to be used for running the application program. For receiving and displaying the iTV application on a TV set, the font has either to be available in the Set Top Box, either as a default font or as a downloaded and in the STB stored font, or else the font has to be included as a file in the broadcast. When storing the application on a storage medium for being played back at a later point of time, the fonts used by the application must also be stored. According to the invention, the fonts are stored in a font library on the storage medium instead of with the specific application that uses them. Thus, the application has not to be modified, e.g. for pointing at a specific font file location. The necessary font files are stored in a separate location on the storage medium, which preferably is an optical disc and it is ensured that there is no duplication of font files in the font library. On playback the font library is searched for the fonts the application wants to use. This principle of the invention will be described in more detail by the following description of embodiments of the invention.
In
In practice, if two applications in the same broadcast use the same font then it only needs to be broadcast once. Generally, the broadcast comprises a set of files being broadcast within the same broadcast section. In the special case, that two applications are broadcast simultaneously in the same broadcast, these applications can use the same font file from the same broadcast. On the other hand, if an application is broadcast at a later point of time and this application uses the same font as an earlier broadcast application, the font is comprised in both broadcasts, without the exception for the below described case of a separate return channel, in which the subsequent download of a font file already being stored on the storage medium can optionally be avoided. According to the invention, the font file is only recorded once on a storage medium, independently to how often it is transmitted with an iTV broadcast which is to be recorded on a storage medium and independently to how many applications using the same font are recorded on the same storage medium.
In
Applications can also be downloaded over a separate return channel, e.g. via an Internet connection, as well as being included in the broadcast. The invention applies equally when this is done. In this case the font library can optionally be checked if the font required by the current application is already stored in the font library on the storage medium. If the font is already stored, the font does not have to be downloaded over the return channel, such as the mentioned Internet connection, and it is avoided that the font file is downloaded. This is advantageous both regarding connection cost and/or bandwidth of the return channel.
When recording the application and fonts, it is thus not possible to extract information on which fonts are to be recorded with the application. This information is only given as a font name when the application is run. According to an embodiment of the invention, it is compared which fonts are listed in the fontindex file 252 and which fonts actually are in the broadcast and the respective other locations, as described above. Only font files which are listed in the font index file 252 and which are not already stored on a storage medium 280 on which the application 251 is to be recorded, are recorded on that storage medium 280. A possible recording is thus illustrated in
In another embodiment of the invention according to
It should be noted that in the MHP standard, the font library's location according to the MHP application has been defined. The application provides a font info file for the fonts the application may use. The font info file stored in the storage media is used to describe all the fonts stored in the storage media. Preferably its structure is the same as the one in the application module. Only the content and size is different from the one in the broadcast stream.
When, at a later point of time, playing back the recorded application module from the storage medium, the application module indicates which font is needed for running the application program. In this case it is checked where the required font is in the font library and/or if the required font is a default font.
Fonts can be deleted that are no longer used when all recordings of applications requiring this specific font are deleted from the storage medium, thus making the storage space of this font available for other purposes.
In another embodiment of the invention, the step 44 is replaced by a step wherein the stored font—in the font library on the storage medium—is replaced by the font in the received iTV application module.
A further embodiment of the invention is illustrated in
In.
According to
In either case the fonts are preferably stored in the same format as used for broadcast. However, further minimisation of used storage space can be achieved by compressing the font files appropriately.
By way of example, the list for other languages is empty.
The present invention has been described above with reference to specific embodiments. However, other embodiments than the preferred above are equally possible within the scope of the appended claims, e.g. different font storage methods than those described above, different file storing structures than those described above, different ways of transporting the application along with the broadcast stream, number of applications or fonts, performing the above method by hardware or software, using glyphs instead of fonts, being implemented in any form of interactive TV, such as MHP, OpenTV, Digital TV Application Software Environment (DASE), or using alternative storage media such as DVD, SFFO (Small Form Factor Optical Storage, etc. Furthermore an application might use a plurality of fonts. According to the invention, not more than one copy of each single of this plurality of fonts is stored on a storage medium.
Furthermore, the term “comprising” does not exclude other elements or steps, the terms “a” and “an” do not exclude a plurality and a single processor or other unit may fulfil the functions of several of the units or circuits recited in the claims.
The application may be summarised as a method (49, 55) of handling fonts in a recorder or a playback-recorder for interactive television. Fonts are stored on a recordable storage medium (220), wherein the fonts are part of a downloaded interactive television application. When recording, the downloaded fonts are stored separate from the application, preferably in a font library on the recordable storage medium, which preferably is a removable medium, preferably an optical storage medium. Each font is only stored in one copy, even when a plurality of applications on the storage medium need that font for running. When playing back the application from the storage medium, indicating information is provided on which fonts form the storage medium in the font library are required for playback of said application from said storage medium. Thus multiple storage of fonts is prevented, minimising needed storage space on the storage medium.
Number | Date | Country | Kind |
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02080307.8 | Dec 2002 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/IB03/05774 | 12/3/2003 | WO | 6/10/2005 |