This project is intended as a replacement for the Mozilla WebVTT library.
The general goals of the project are to A) include support for the TTML specification, and B) to improve API usability for WebVTT.
This library includes libexpat, though support for alternative XML libraries, though support for alternative XML libraries such as PugiXML may be added later on, for certain use-cases. As the primary use-case is use within a browser, stream parsing is a nice thing to have.
I've added a demo, for your viewing pleasure! This will be moved to the Wiki page soon, but I thought it would be a good idea to give an idea how this library can be used. It is of course capable of much more than this, of course. An easier to read API reference is coming soon.
Example stream-oriented WebVTT Parsing and displaying on the console:
#include <TimedText/WebVTTParser.h>
#include <TimedText/SynchronousBuffer.h>
#include <fstream>
#include <string>
#include <cstdio>
int
main(int argc, char **argv) {
// Make a nicer name for a List of Cues, since we refer to it
// a lot.
typedef TimedText::List<TimedText::Cue> CueList;
// Use first command line parameter as filename
if(argc < 2)
return 1;
// Client object is notified
struct WebVTTFileParser : public TimedText::Client
{
WebVTTFileParser(const char *file)
: fileName(file)
{
parser = new TimedText::WebVTTParser(buffer, this);
}
~WebVTTFileParser()
{
delete parser;
}
// Read and parse the file in chunks of 4096 bytes
bool parse()
{
file.open(fileName.c_str(), std::ios::in|std::ios::binary);
if(!file.good())
return false;
char buf[0x1000] = "";
while(true) {
bool final = false;
std::streamsize n = file.readsome(buf, sizeof(buf));
if(n < 0x1000)
final = true;
buffer.refill(buf, n, final);
if(!parser->parse())
return false;
if(final)
break;
}
return true;
}
// This message is called by the parser to notify the client that
// there are new Cues available
void cuesAvailable()
{
CueList newCues;
parser->parsedCues(newCues);
myCues += newCues;
}
TimedText::SynchronousBuffer buffer;
TimedText::WebVTTParser *parser;
std::string fileName;
std::ifstream file;
CueList myCues;
};
WebVTTFileParser p(argv[1]);
if(p.parse()) {
// Create a Node visitor to visit and perform some action on each Node in the
// tree of CueText Nodes.
//
// This one will print TextNodes at indents depending on what level branch
// they are on.
class Visitor : public TimedText::NodeVisitor
{
public:
Visitor() : indent(0) {}
bool enter(const TimedText::Node &node)
{
indent += 2;
return true;
}
void leave(const TimedText::Node &node)
{
indent -= 2;
}
void visit(TimedText::Node &node)
{
if(node.element() == TimedText::TextNode) {
::printf("%*s%s%c", indent, "", node.text().text(),
node.text().endsWith('\n') ? '\0' : '\n');
}
}
int indent;
};
for(CueList::iterator it = p.myCues.begin(); it < p.myCues.end(); ++it) {
// Print the Cue ID, if one is present
if(!it->id().isEmpty())
::printf("%s\n", it->id().text());
// Print the start time and end time of the cue, in seconds (double)
::printf("%f --> %f\n", it->startTime().toSeconds(), it->endTime().toSeconds());
// Parse the CueText for the given cue, and walk it.
TimedText::WebVTTParser::parseCuetext(*it);
Visitor v;
it->visit(v);
}
}
}
Copyright (c) 2013 Caitlin Potter and Contributors All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
- Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.