sjs/media
1
0
Fork 0
mirror of https://github.com/samsonjs/media.git synced 2026-04-27 15:07:40 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Redesign states of the SubtitleExtractor.

Browse source 
Simplifies the SubtitleExtractor implementation. Makes the extractor
more aligned with the Extractor interface documentation by removing
STATE_DECODING in which extractor was doing nothing in term of input
and output while returning RESULT_CONTINUE at the same time.

PiperOrigin-RevId: 395267468
This commit is contained in:
apodob 2021-09-07 17:42:31 +01:00 committed by Oliver Woodman
parent 9949424da4
commit 66335ab6f5
1 changed files with 29 additions and 62 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

91
library/extractor/src/main/java/com/google/android/exoplayer2/extractor/subtitle/SubtitleExtractor.java
View file

@ -47,33 +47,20 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
/** Generic extractor for extracting subtitles from various subtitle formats. */
public class SubtitleExtractor implements Extractor {
@IntDef(
value = {
STATE_CREATED,
STATE_INITIALIZED,
STATE_READING,
STATE_DECODING,
STATE_WRITING,
STATE_FINISHED,
STATE_RELEASED
})
@Retention(RetentionPolicy.SOURCE)
@IntDef({STATE_CREATED, STATE_INITIALIZED, STATE_EXTRACTING, STATE_FINISHED, STATE_RELEASED})
private @interface State {}
/** The extractor has been created. */
private static final int STATE_CREATED = 0;
/** The extractor has been initialized. */
private static final int STATE_INITIALIZED = 1;
/** The extractor is reading data from the input. */
private static final int STATE_READING = 2;
/** The extractor is queueing data for decoding. */
private static final int STATE_DECODING = 3;
/** The extractor is writing data to the output. */
private static final int STATE_WRITING = 4;
/** The extractor has finished writing. */
private static final int STATE_FINISHED = 5;
/** The extractor has bean released */
private static final int STATE_RELEASED = 6;
/** The extractor is reading from input and writing to output. */
private static final int STATE_EXTRACTING = 2;
/** The extractor has finished. */
private static final int STATE_FINISHED = 3;
/** The extractor has been released. */
private static final int STATE_RELEASED = 4;
private static final int DEFAULT_BUFFER_SIZE = 1024;
@ -126,29 +113,26 @@ public class SubtitleExtractor implements Extractor {
@Override
public int read(ExtractorInput input, PositionHolder seekPosition) throws IOException {
switch (state) {
case STATE_INITIALIZED:
prepareMemory(input);
state = readFromInput(input) ? STATE_DECODING : STATE_READING;
return Extractor.RESULT_CONTINUE;
case STATE_READING:
state = readFromInput(input) ? STATE_DECODING : STATE_READING;
return Extractor.RESULT_CONTINUE;
case STATE_DECODING:
queueDataToDecoder();
state = STATE_WRITING;
return RESULT_CONTINUE;
case STATE_WRITING:
writeToOutput();
state = STATE_FINISHED;
return Extractor.RESULT_END_OF_INPUT;
case STATE_FINISHED:
return Extractor.RESULT_END_OF_INPUT;
case STATE_CREATED:
case STATE_RELEASED:
default:
throw new IllegalStateException();
checkState(state != STATE_CREATED && state != STATE_RELEASED);
if (state == STATE_INITIALIZED) {
subtitleData.reset(
input.getLength() != C.LENGTH_UNSET
? Ints.checkedCast(input.getLength())
: DEFAULT_BUFFER_SIZE);
bytesRead = 0;
state = STATE_EXTRACTING;
}
if (state == STATE_EXTRACTING) {
boolean inputFinished = readFromInput(input);
if (inputFinished) {
decodeAndWriteToOutput();
state = STATE_FINISHED;
}
}
if (state == STATE_FINISHED) {
return RESULT_END_OF_INPUT;
}
return RESULT_CONTINUE;
}
@Override
@ -166,13 +150,6 @@ public class SubtitleExtractor implements Extractor {
state = STATE_RELEASED;
}
private void prepareMemory(ExtractorInput input) {
subtitleData.reset(
input.getLength() != C.LENGTH_UNSET
? Ints.checkedCast(input.getLength())
: DEFAULT_BUFFER_SIZE);
}
/** Returns whether reading has been finished. */
private boolean readFromInput(ExtractorInput input) throws IOException {
if (subtitleData.capacity() == bytesRead) {
@ -186,7 +163,9 @@ public class SubtitleExtractor implements Extractor {
return readResult == C.RESULT_END_OF_INPUT;
}
private void queueDataToDecoder() throws IOException {
/** Decodes subtitle data and writes samples to the output. */
private void decodeAndWriteToOutput() throws IOException {
checkStateNotNull(this.trackOutput);
try {
@Nullable SubtitleInputBuffer inputBuffer = subtitleDecoder.dequeueInputBuffer();
while (inputBuffer == null) {
@ -196,23 +175,11 @@ public class SubtitleExtractor implements Extractor {
inputBuffer.ensureSpaceForWrite(bytesRead);
inputBuffer.data.put(subtitleData.getData(), /* offset= */ 0, bytesRead);
subtitleDecoder.queueInputBuffer(inputBuffer);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new InterruptedIOException();
} catch (SubtitleDecoderException e) {
throw ParserException.createForMalformedContainer("SubtitleDecoder failed.", e);
}
}
private void writeToOutput() throws IOException {
checkStateNotNull(this.trackOutput);
try {
@Nullable SubtitleOutputBuffer outputBuffer = subtitleDecoder.dequeueOutputBuffer();
while (outputBuffer == null) {
Thread.sleep(5);
outputBuffer = subtitleDecoder.dequeueOutputBuffer();
}
for (int i = 0; i < outputBuffer.getEventTimeCount(); i++) {
List<Cue> cues = outputBuffer.getCues(outputBuffer.getEventTime(i));
byte[] cuesSample = cueEncoder.encode(cues);