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Noop naming generalization for H265Reader

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This change generalizes the concept of "reading parameter sets" to
"reading prefix NAL units", ahead of a change that will treat AUD
and suffix SEI NAL units in the same way.

The change also introduces some static isXxxNalUnit methods for
clarity.

Issue: #7113
PiperOrigin-RevId: 307376967
This commit is contained in:
olly 2020-04-20 12:54:52 +01:00 committed by Oliver Woodman
parent eb8c174b4c
commit 9a7290000c
1 changed files with 31 additions and 23 deletions
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54
library/extractor/src/main/java/com/google/android/exoplayer2/extractor/ts/H265Reader.java
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@ -65,7 +65,7 @@ public final class H265Reader implements ElementaryStreamReader {
private final NalUnitTargetBuffer sps;
private final NalUnitTargetBuffer pps;
private final NalUnitTargetBuffer prefixSei;
private final NalUnitTargetBuffer suffixSei; // TODO: Are both needed?
private final NalUnitTargetBuffer suffixSei;
private long totalBytesWritten;
// Per packet state that gets reset at the start of each packet.
@ -424,17 +424,17 @@ public final class H265Reader implements ElementaryStreamReader {
private final TrackOutput output;
// Per NAL unit state. A sample consists of one or more NAL units.
private long nalUnitStartPosition;
private long nalUnitPosition;
private boolean nalUnitHasKeyframeData;
private int nalUnitBytesRead;
private long nalUnitTimeUs;
private boolean lookingForFirstSliceFlag;
private boolean isFirstSlice;
private boolean isFirstParameterSet;
private boolean isFirstPrefixNalUnit;
// Per sample state that gets reset at the start of each sample.
private boolean readingSample;
private boolean writingParameterSets;
private boolean readingPrefix;
private long samplePosition;
private long sampleTimeUs;
private boolean sampleIsKeyframe;
@ -446,31 +446,29 @@ public final class H265Reader implements ElementaryStreamReader {
public void reset() {
lookingForFirstSliceFlag = false;
isFirstSlice = false;
isFirstParameterSet = false;
isFirstPrefixNalUnit = false;
readingSample = false;
writingParameterSets = false;
readingPrefix = false;
}
public void startNalUnit(
long position, int offset, int nalUnitType, long pesTimeUs, boolean hasOutputFormat) {
isFirstSlice = false;
isFirstParameterSet = false;
isFirstPrefixNalUnit = false;
nalUnitTimeUs = pesTimeUs;
nalUnitBytesRead = 0;
nalUnitStartPosition = position;
nalUnitPosition = position;
if (nalUnitType >= VPS_NUT) {
if (!writingParameterSets && readingSample) {
// This is a non-VCL NAL unit, so flush the previous sample.
if (!isVclBodyNalUnit(nalUnitType)) {
if (readingSample && !readingPrefix) {
if (hasOutputFormat) {
outputSample(offset);
}
readingSample = false;
}
if (nalUnitType <= PPS_NUT) {
// This sample will have parameter sets at the start.
isFirstParameterSet = !writingParameterSets;
writingParameterSets = true;
if (isPrefixNalUnit(nalUnitType)) {
isFirstPrefixNalUnit = !readingPrefix;
readingPrefix = true;
}
}
@ -492,30 +490,40 @@ public final class H265Reader implements ElementaryStreamReader {
}
public void endNalUnit(long position, int offset, boolean hasOutputFormat) {
if (writingParameterSets && isFirstSlice) {
if (readingPrefix && isFirstSlice) {
// This sample has parameter sets. Reset the key-frame flag based on the first slice.
sampleIsKeyframe = nalUnitHasKeyframeData;
writingParameterSets = false;
} else if (isFirstParameterSet || isFirstSlice) {
readingPrefix = false;
} else if (isFirstPrefixNalUnit || isFirstSlice) {
// This NAL unit is at the start of a new sample (access unit).
if (hasOutputFormat && readingSample) {
// Output the sample ending before this NAL unit.
int nalUnitLength = (int) (position - nalUnitStartPosition);
int nalUnitLength = (int) (position - nalUnitPosition);
outputSample(offset + nalUnitLength);
}
samplePosition = nalUnitStartPosition;
samplePosition = nalUnitPosition;
sampleTimeUs = nalUnitTimeUs;
readingSample = true;
sampleIsKeyframe = nalUnitHasKeyframeData;
readingSample = true;
}
}
private void outputSample(int offset) {
@C.BufferFlags int flags = sampleIsKeyframe ? C.BUFFER_FLAG_KEY_FRAME : 0;
int size = (int) (nalUnitStartPosition - samplePosition);
int size = (int) (nalUnitPosition - samplePosition);
output.sampleMetadata(sampleTimeUs, flags, size, offset, null);
}
}
/** Returns whether a NAL unit type is one that occurs before any VCL NAL units in a sample. */
private static boolean isPrefixNalUnit(int nalUnitType) {
// TODO: Include AUD_NUT and PREFIX_SEI_NUT
return VPS_NUT <= nalUnitType && nalUnitType <= PPS_NUT;
}
/** Returns whether a NAL unit type is one that occurs in the VLC body of a sample. */
private static boolean isVclBodyNalUnit(int nalUnitType) {
// TODO: Include SUFFIX_SEI_NUT
return nalUnitType < VPS_NUT;
}
}
}