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Add manifestless captions support. This code fits into the pre-existing

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captions fetcher architecture.

1.  ManifestlessCaptionsMetadata

Other captions fetchers must first fetch a manifest (HLS or manifest) to
discover captions tracks.  This process does not exist for manifestless.  All
we need to do is scan the FormatStream's for the right itag, so this is an
all-static class.

2.  ManifestlessSubtitleWindowProvider

Once a captions track is selected, a subtitles provider is instantiated.  This
is the main interface used by the player to retrieve captions according to
playback position.  This class stores fetched captions in a tree index by time
for efficient lookups.  Background captions fetches are used to populate
the tree.

3.  ManifestlessCaptionsFetch

Captions are fetched one segment at a time.  One instance of this object
is required per fetch.  It performs a blocking fetch on call(), and is
intended to be submitted to a background-thread executor.

4.  ManifestlessCaptionsFetch.CaptionSegment

This is the result of the caption fetch.  These values are used to populate
the captions tree.

Manifestlessness

The initial request is always a headm request.  There is a separate tree
of every segment indexed by start time.  This tree is used to improve
manifestless sequence number calculation.  Once we have data for the current
timestamp, we walk forward through the tree to find the next unfetched
sequence number, and fetch that.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=177385094
This commit is contained in:
mdoucleff 2017-11-29 16:59:41 -08:00 committed by Oliver Woodman
parent 800cfeea3d
commit f0f726dfa9
3 changed files with 7 additions and 5 deletions
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4
library/core/src/main/java/com/google/android/exoplayer2/text/webvtt/WebvttCssStyle.java
View File

@ -31,10 +31,11 @@ import java.util.List;
* @see <a href="https://w3c.github.io/webvtt/#applying-css-properties">W3C specification - Apply
* CSS properties</a>
*/
/* package */ final class WebvttCssStyle {
public final class WebvttCssStyle {
public static final int UNSPECIFIED = -1;
/** Style flag enum */
@Retention(RetentionPolicy.SOURCE)
@IntDef(flag = true, value = {UNSPECIFIED, STYLE_NORMAL, STYLE_BOLD, STYLE_ITALIC,
STYLE_BOLD_ITALIC})
@ -44,6 +45,7 @@ import java.util.List;
public static final int STYLE_ITALIC = Typeface.ITALIC;
public static final int STYLE_BOLD_ITALIC = Typeface.BOLD_ITALIC;
/** Font size unit enum */
@Retention(RetentionPolicy.SOURCE)
@IntDef({UNSPECIFIED, FONT_SIZE_UNIT_PIXEL, FONT_SIZE_UNIT_EM, FONT_SIZE_UNIT_PERCENT})
public @interface FontSizeUnit {}

4
library/core/src/main/java/com/google/android/exoplayer2/text/webvtt/WebvttCue.java
View File

@ -23,7 +23,7 @@ import com.google.android.exoplayer2.text.Cue;
/**
* A representation of a WebVTT cue.
*/
/* package */ final class WebvttCue extends Cue {
public final class WebvttCue extends Cue {
public final long startTime;
public final long endTime;
@ -59,7 +59,7 @@ import com.google.android.exoplayer2.text.Cue;
* Builder for WebVTT cues.
*/
@SuppressWarnings("hiding")
public static final class Builder {
public static class Builder {
private static final String TAG = "WebvttCueBuilder";

4
library/core/src/main/java/com/google/android/exoplayer2/text/webvtt/WebvttCueParser.java
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@ -45,7 +45,7 @@ import java.util.regex.Pattern;
/**
* Parser for WebVTT cues. (https://w3c.github.io/webvtt/#cues)
*/
/* package */ final class WebvttCueParser {
public final class WebvttCueParser {
public static final Pattern CUE_HEADER_PATTERN = Pattern
.compile("^(\\S+)\\s+-->\\s+(\\S+)(.*)?$");
@ -90,7 +90,7 @@ import java.util.regex.Pattern;
* @param styles List of styles defined by the CSS style blocks preceeding the cues.
* @return Whether a valid Cue was found.
*/
/* package */ boolean parseCue(ParsableByteArray webvttData, WebvttCue.Builder builder,
public boolean parseCue(ParsableByteArray webvttData, WebvttCue.Builder builder,
List<WebvttCssStyle> styles) {
String firstLine = webvttData.readLine();
if (firstLine == null) {