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Add private @SeekHeader IntDef to Mp3Extractor

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Also use `switch` instead of `if-else`.

PiperOrigin-RevId: 597004322
This commit is contained in:
ibaker 2024-01-09 12:01:54 -08:00 committed by Copybara-Service
parent 1c1d4d506d
commit 143d782b1c
1 changed files with 38 additions and 25 deletions
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63
libraries/extractor/src/main/java/androidx/media3/extractor/mp3/Mp3Extractor.java
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@ -16,6 +16,7 @@
package androidx.media3.extractor.mp3;
import static java.lang.annotation.ElementType.TYPE_USE;
import static java.lang.annotation.RetentionPolicy.SOURCE;
import androidx.annotation.IntDef;
import androidx.annotation.Nullable;
@ -48,7 +49,6 @@ import java.io.EOFException;
import java.io.IOException;
import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import org.checkerframework.checker.nullness.qual.EnsuresNonNull;
import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
@ -67,7 +67,7 @@ public final class Mp3Extractor implements Extractor {
* {@link #FLAG_ENABLE_INDEX_SEEKING} and {@link #FLAG_DISABLE_ID3_METADATA}.
*/
@Documented
@Retention(RetentionPolicy.SOURCE)
@Retention(SOURCE)
@Target(TYPE_USE)
@IntDef(
flag = true,
@ -142,6 +142,12 @@ public final class Mp3Extractor implements Extractor {
/** Mask that includes the audio header values that must match between frames. */
private static final int MPEG_AUDIO_HEADER_MASK = 0xFFFE0C00;
@Documented
@Target(TYPE_USE)
@Retention(SOURCE)
@IntDef(value = {SEEK_HEADER_XING, SEEK_HEADER_INFO, SEEK_HEADER_VBRI, SEEK_HEADER_UNSET})
private @interface SeekHeader {}
private static final int SEEK_HEADER_XING = 0x58696e67;
private static final int SEEK_HEADER_INFO = 0x496e666f;
private static final int SEEK_HEADER_VBRI = 0x56425249;
@ -506,30 +512,37 @@ public final class Mp3Extractor implements Extractor {
(synchronizedHeader.version & 1) != 0
? (synchronizedHeader.channels != 1 ? 36 : 21) // MPEG 1
: (synchronizedHeader.channels != 1 ? 21 : 13); // MPEG 2 or 2.5
int seekHeader = getSeekFrameHeader(frame, xingBase);
@SeekHeader int seekHeader = getSeekFrameHeader(frame, xingBase);
@Nullable Seeker seeker;
if (seekHeader == SEEK_HEADER_XING || seekHeader == SEEK_HEADER_INFO) {
seeker = XingSeeker.create(input.getLength(), input.getPosition(), synchronizedHeader, frame);
if (seeker != null && !gaplessInfoHolder.hasGaplessInfo()) {
// If there is a Xing header, read gapless playback metadata at a fixed offset.
switch (seekHeader) {
case SEEK_HEADER_XING:
case SEEK_HEADER_INFO:
seeker =
XingSeeker.create(input.getLength(), input.getPosition(), synchronizedHeader, frame);
if (seeker != null && !gaplessInfoHolder.hasGaplessInfo()) {
// If there is a Xing header, read gapless playback metadata at a fixed offset.
input.resetPeekPosition();
input.advancePeekPosition(xingBase + 141);
input.peekFully(scratch.getData(), 0, 3);
scratch.setPosition(0);
gaplessInfoHolder.setFromXingHeaderValue(scratch.readUnsignedInt24());
}
input.skipFully(synchronizedHeader.frameSize);
if (seeker != null && !seeker.isSeekable() && seekHeader == SEEK_HEADER_INFO) {
// Fall back to constant bitrate seeking for Info headers missing a table of contents.
return getConstantBitrateSeeker(input, /* allowSeeksIfLengthUnknown= */ false);
}
break;
case SEEK_HEADER_VBRI:
seeker =
VbriSeeker.create(input.getLength(), input.getPosition(), synchronizedHeader, frame);
input.skipFully(synchronizedHeader.frameSize);
break;
case SEEK_HEADER_UNSET:
default:
// This frame doesn't contain seeking information, so reset the peek position.
seeker = null;
input.resetPeekPosition();
input.advancePeekPosition(xingBase + 141);
input.peekFully(scratch.getData(), 0, 3);
scratch.setPosition(0);
gaplessInfoHolder.setFromXingHeaderValue(scratch.readUnsignedInt24());
}
input.skipFully(synchronizedHeader.frameSize);
if (seeker != null && !seeker.isSeekable() && seekHeader == SEEK_HEADER_INFO) {
// Fall back to constant bitrate seeking for Info headers missing a table of contents.
return getConstantBitrateSeeker(input, /* allowSeeksIfLengthUnknown= */ false);
}
} else if (seekHeader == SEEK_HEADER_VBRI) {
seeker = VbriSeeker.create(input.getLength(), input.getPosition(), synchronizedHeader, frame);
input.skipFully(synchronizedHeader.frameSize);
} else { // seekerHeader == SEEK_HEADER_UNSET
// This frame doesn't contain seeking information, so reset the peek position.
seeker = null;
input.resetPeekPosition();
}
return seeker;
}
@ -560,7 +573,7 @@ public final class Mp3Extractor implements Extractor {
* the provided {@code frame} may have seeking metadata, or {@link #SEEK_HEADER_UNSET} otherwise.
* If seeking metadata is present, {@code frame}'s position is advanced past the header.
*/
private static int getSeekFrameHeader(ParsableByteArray frame, int xingBase) {
private static @SeekHeader int getSeekFrameHeader(ParsableByteArray frame, int xingBase) {
if (frame.limit() >= xingBase + 4) {
frame.setPosition(xingBase);
int headerData = frame.readInt();