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parse x-timestamp-map #4

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Mar 13, 2017
Merged

parse x-timestamp-map #4

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69f8609
parse x-timestamp-map
Feb 9, 2017
9864d00
update README
Mar 1, 2017
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24 changes: 18 additions & 6 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@ This is a fork of vttjs with some changes that are used by Video.js.
- [oncue(cue)](#oncuecue)
- [onflush()](#onflush)
- [onparsingerror(error)](#onparsingerrorerror)
- [ontimestampmap(timestampmap)](#ontimestampmaptimestampmap)
- [WebVTT.convertCueToDOMTree(window, cuetext)](#webvttconvertcuetodomtreewindow-cuetext)
- [WebVTT.processCues(window, cues, overlay)](#webvttprocesscueswindow-cues-overlay)
- [ParsingError](#parsingerror)
Expand Down Expand Up @@ -159,6 +160,17 @@ parser.onparsingerror = function(e) {
};
```

####ontimestampmap(timestampmap)####

Is invoked when an `X-TIMESTAMP-MAP` metadata header ([defined here](https://tools.ietf.org/html/draft-pantos-http-live-streaming-20#section-3.5)) is parsed. This header maps WebVTT cue timestamps to MPEG-2 (PES) timestamps in other Renditions of the Variant Stream.

```js
parser.ontimestampmap = function(timestamp) {
console.log('LOCAL:', timestamp.LOCAL);
console.log('MPEGTS:', timestamp.MPEGTS);
};
```

####WebVTT.convertCueToDOMTree(window, cuetext)####

Parses the cue text handed to it into a tree of DOM nodes that mirrors the internal WebVTT node structure of
Expand Down Expand Up @@ -538,18 +550,18 @@ for the task. If you want to know more about `cue2json` you can run it directly
like so:

```bash
$ ./bin/cue2json.js
$ ./bin/cue2json.js
$ Generate JSON test files from a reference VTT file.
$ Usage: node ./bin/cue2json.js [options]
$
$
$ Options:
$ -v, --vtt Path to VTT file.
$ -v, --vtt Path to VTT file.
$ -d, --dir Path to test directory. Will recursively find all JSON files with matching VTT files and rewrite them.
$ -c, --copy Copies the VTT file to a JSON file with the same name.
$ -p, --process Generate a JSON file of the output returned from the processing model.
$ -c, --copy Copies the VTT file to a JSON file with the same name.
$ -p, --process Generate a JSON file of the output returned from the processing model.
```

**Notes:**
**Notes:**

* `cue2json` utilizes the last development build done. This is why the Grunt `run` task is
good as you don't have to remember to build it yourself. If you don't build it yourself then you could
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51 changes: 43 additions & 8 deletions lib/vtt.js
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Expand Up @@ -1138,16 +1138,51 @@
}
}

// 3.2 WebVTT metadata header syntax
function parseHeader(input) {
parseOptions(input, function (k, v) {
switch (k) {
case "Region":
// 3.3 WebVTT region metadata header syntax
parseRegion(v);
// draft-pantos-http-live-streaming-20
// https://tools.ietf.org/html/draft-pantos-http-live-streaming-20#section-3.5
// 3.5 WebVTT
function parseTimestampMap(input) {
var settings = new Settings();

parseOptions(input, function(k, v) {
switch(k) {
case "MPEGT":
settings.integer(k + 'S', v);
break;
case "LOCA":
settings.set(k + 'L', parseTimeStamp(v));
break;
}
}, /:/);
}, /[^\d]:/, /,/);

self.ontimestampmap && self.ontimestampmap({
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so, ontimestampmap is a method on the parser that will be called with the MPEGTS and LOCAL times? Does it mean that the user still needs to manually shift all the timestamps by this?

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Yes, the user would have to manually shift the timestamps. The timestamp map tag only gives a mapping from cue time to TS time, but the mapping from TS to display time is still needed for the shift. I think this approach is the easiest instead of storing state on the parse for the extra mapping

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hm... maybe it's the best option; it just seems to be only half complete this way.

"MPEGTS": settings.get("MPEGTS"),
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this is hilarious.

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And by this, I mean LOCA and MPEGT.

"LOCAL": settings.get("LOCAL")
});
}

// 3.2 WebVTT metadata header syntax
function parseHeader(input) {
if (input.match(/X-TIMESTAMP-MAP/)) {
// This line contains HLS X-TIMESTAMP-MAP metadata
parseOptions(input, function(k, v) {
switch(k) {
case "X-TIMESTAMP-MAP":
parseTimestampMap(v);
break;
}
}, /=/);
} else {
parseOptions(input, function (k, v) {
switch (k) {
case "Region":
// 3.3 WebVTT region metadata header syntax
parseRegion(v);
break;
}
}, /:/);
}

}

// 5.1 WebVTT file parsing.
Expand Down