The DVB standard, issued by Digital Video Broadcasting consortium, defines technology for transmission of subtitles as part of the program stream.
It allows viewers to choose whether or not to display the subtitles, as long as they have digital receiver capable of decoding the DVB compliant subtitle stream.
The DVB standard defines two ways of subtitle delivery. The first one is character based with each character represented by an individual code.
The second one is image based. The subtitle text is rendered as an individual image and then encoded into the DVB subtitle stream.
EZConvert uses the image based method for delivering DVB subtitles because it has proved to be more popular and reliable, and offers more advantages over the character based method:
▪The subtitle font, size and position can be adjusted and controlled by the editor.
▪Presentation effects like outline, box and stripe can be applied.
▪All languages and text scripts are supported because the subtitles are transmitted as images.
▪The subtitles may be output in higher resolution and in greater quality.
The DVB subtitle stream needs to be multiplexed together with the audio and video streams into the program stream of the digital material before the actual transmission of the program.
Currently EZConvert could create and output DVB subtitle streams for use by ProMedia Carbon and Manzanita MP2TSME as well as Generic DVB Elementary Stream.
All three of them will produce fully compliant DVB subtitle stream but it will be customized for the specific needs and requirements of either ProMedia Carbon or Manzanita applications.
Compatibility
DVB Subtitles for |
The output DVB subtitles stream is optimized for use by ProMedia Carbon. Note: Please note that DVB Subtitles cannot be encoded by using the ProMedia Carbon GUI or ADMIN tools. The Job Submit function shall be considered instead. The Rhozet API guide explains in details how to use DVB subtitles and ProMedia Carbon in your workflow. |
DVB Subtitles for |
The output DVB subtitles stream is optimized for use by Manzanita MP2TSME multiplexer. Two files are created: .dvb elementary subtitle stream binary data and xml based description file with .idx extension. Note: Please mind that in Manzanita's user interface you need to Insert Private Stream and then add the .idx XML file. |
MPEG-TS |
The output will be MPEG Transport Stream (mpeg-ts) with .dvb extension compatible for muxing by FFMPEG. Note: The proccess of muxing the output can be automated via EZConvert's Watch Folder by configuring Post Conversion Event to do that. |
Generic DVB ES |
The Generic DVB Elementary Stream is a sequence of PES packages, starting with packet_start_code_prefix (0x000001), containing PTS and Data field with the encoded subtitles. For more information please refer to ISO/IEC 13818-1 and ETSI EN 300 743. |
General
Recut/Offset |
Allows you to Recut/Offset the subtitles during the export. From the drop-down menu you can choose between the following options: None - doesn't recut or offset the subtitles and they will be exported with their original timing. Manual - allows you manually specify the offset for the recut. Auto - automatically offsets the timing using the first subtitle's In-cue. All timecodes are offset backward with the first subtitle's In-cue rounded down to the closes hour. For example if the first subtitle originally starts at 10:00:32:21 after applying the recut it's start time will become 00:00:32:21. Programme Start TC - automatically subtracts the value of the Programme Start TimeCode metadata parameter if available in the input file. Note that this parameter is supported for EBU STL, EBU-TT, EZT or EZTXML file formats only. Video Start TC - automatically gets video's start time from the input EZT or EZTXML file and uses it to recut/offset the subtitles. |
Pixel Color Depth |
Determines the quality of the DVB subtitles. Choosing higher value for the pixel color depth will increase the quality of the DVB subtitles but at the same time will increase their size. |
Stream properties
ISO Language - The DVB standard allows different languages to be transmitted simultaneously and viewers are able to choose which one to activate by the subtitle selection menu of their TV set.
Code is the 3 letters language code specified by the ISO standard. When you choose a language this field is automatically set with the default code. If it is not the correct one you can type a new value by hand.
Subtitling type indicates if these are regular subtitles or has more descriptive functions for deaf and heard of hearing.
Stream ID - allows you change the PID of the DVB subtitle stream. This option is available only when exporting MPEG-TS (FFMPEG compatible) DVB subtitles.
Options
Please mind that all other remaining options shall be used only if there is a problem with the default parameters.
They are intended to solve some compatibility issues which appear on different DVB decoding devices.
Skip Display Definition Segment |
Discards Display Definition Segment attribute from the DVB stream. |
Use 0x00000000 for transparent CLUT entry |
The transparent color could be 0x00000000 or black with maximum possible level of transparency (255). |
Use Region fill flag |
Forces the region_fill_flag. |
Full width regions |
Instead of creating display regions with the size of the text this option will create region with the width of the video instead. |
Full width Bitmaps |
Creates bitmaps to fill in the whole display region. Some decoding devices might not be able to correctly display partially filled in or empty regions. |
Send non-empty PCS on hide subtitle |
By default each subtitle will hide by transmitting an empty page which doesn't contain any regions. This, however, might turn into a problem for some devices and by activating this option EZConvert will create a page containing region that equals the size of the lastly displayed one, instead of a page without region. |
Send empty bitmaps |
If the Send non-empty PCS... option is already activated the display region will be filled by a transparent bitmap. |