Fused and Electronic Subtitling

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Now you can watch Movies on TV sets with subtitles in you regional languages - Thanks to the efforts of a crack team at C-DAC supported by NFDC and Doordarshan.

Language Independent Programme Subtitles (LIPS) Technology has provided unique solutions for a multi-lingual country like India. The system makes it possible to broadcast the same programme from a central place and provide different language subtitles simultaneously in different states. It has been deployed by C-DAC, Pune in collaboration with NFDC and Doordarshan.

Doordarshan makes use os the versatile INSAT system which makes it possible to feed the same signal to all the parts of India with Electronic subtitles. The data for subtitles in the various languages is inserted digitally in the vertical interval of video signal. The programmes are uplinked from Delhi on S-Band. Two channels namely S1 and S2 are used for the network programmes. Channel S1 carries the signal meant to be used by state capital for decoding subtitles. Channel S2 carries the signal with fused Hindi subtitles. This is done at Delhi Doordarshan Kendra.

LIPS decoder Installations in India

The state capitals have a frequency allocation for the regional service in the C-band. The northern states needing Hindi subtitles, simply relay the signal got from S2. Other state capitals use the LIPS decoder to select the regional languageon the signal got from S1 and then it is uplinked in their regional service. This way the transmitters throughout that state relay the programme with the regional language subtitles.


LIPS decoder installation at regional relay centres

Other possibilities include the usage of subtitle decoders at home. Additional audio tracks may also be multiplexed on the satellite signal and then selected by the cable operators.

Subtitling procedure:
The electronic subtitles are put on the master tape before it goes for telecast. This procedure consists of subtitling in each language separately and then merging the different language subtitles together.

For subtitling in each language, a person with good language skills watches the cassette with subtitles in a link language and then translates it into another language. The time codes for each subtitle are added to ensure time-sync. With the help of subedit software, on-line data-entry is done in that language. LIPS Creation Station has all the facilities for creating subtitles, previewing them on video and editing the subtitles. All mistakes are corrected by previewing the film subtitles and using Indian language spell-checkers. Next, the subtitles data is validated for consistency.

Then the different language subtitles are merged and the subtitle data is generated. This is transferred to the video-tape with the help of LIPS master station. This digitally encoded subtitle tape is used for telecast.

Subtitling cell:
In order to meet the growing requirement of subtitled programmes, a subtitling cell has been set upwithin the precincts of C-DAC under the CMDS project funded by Department of Electronics. The cell has the equipment for creation in different languages and merging them for recording on the master tape.. The languages available for subtitling include Assamese, Bengali, Gujrati, Hindi, Kannada, Marathi, Malayalam, Oriya, Tamil and Telugu. Amongst the foreign languages the ones supported are English, French, German, Spanish, Italian, Portugese, Hungarian, Norwegian, Swedish and Danish. For improving the quality of subtitles, spell-checkers are used to correct the spelling mistakes.

Visual Readability Index:
The feedback from viewers has guided us to conceive os a special technique named VRI(visual readability index). The difficulty faced by the viewers is that the subtitles do not stay long enough for reading at an average speed.. Earlier the subtitle was shown for the same duration for which the dialogue was spoken. This leads to a problem since reading requires more time as compared to voice. Hence, based on the parameters like length of the subtitle, language, and the average reading speed we can optimize the VRI for each subtitle separately. The subtitle's out-time is modified with respect to in-time. This will enhance the comfort while watching subtitles and make the technique more popular.

New Applications:
There is a good scope for subtitling more programmes of national interest and the ones having mass appeal. Tele-serials and tele magazines can reach larger audience with the help of regional language subtitles. For other applications, fused subtitling is a simple affair on the LIPS Creation Station.

Past, Present and Future:
"Salaam Bombay" was the first movie to be telecast on by Doordarshan with simultaneous multi-lingual subtitles in January 93. Another milestone was the telecast of "Bhavani Bhavai" in March 94 when simultaneous audio was provided in Hindi and Gujrati. There is a plan to offer this technique for more movies and programmes in future.

Presently, the award winning movie that are telecast on Sunday by Doordarshan network are providing the subtitles in the regional language for the viewers in different parts of the country. This has been liked by the public and they are giving valuable feedback to improve the system further.

There is a plan to design and develop a dubbing station which will extend this technology to voice as well. Digital techniques for compression and decompression are well suited for reducing the bandwidth requirement and enhance the transmission quality as well.