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Detect frames using first_slice_segment_in_pic_flag.

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This commit is contained in:
Andrew Lewis 2015-07-10 11:46:30 +01:00
parent ead8abf09f
commit c47c6816e4
1 changed files with 30 additions and 19 deletions
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49
library/src/main/java/com/google/android/exoplayer/extractor/ts/H265Reader.java
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@ -35,17 +35,16 @@ import java.util.Collections;
private static final String TAG = "H265Reader";
// nal_unit_type values from H.265/HEVC (2014) Table 7-1.
private static final int RASL_R = 9;
private static final int BLA_W_LP = 16;
private static final int BLA_W_RADL = 17;
private static final int BLA_N_LP = 18;
private static final int IDR_W_RADL = 19;
private static final int IDR_N_LP = 20;
private static final int CRA_NUT = 21;
private static final int VPS_NUT = 32;
private static final int SPS_NUT = 33;
private static final int PPS_NUT = 34;
private static final int PREFIX_SEI_NUT = 39;
private static final int SUFFIX_SEI_NUT = 40;
@ -122,10 +121,7 @@ import java.util.Collections;
int nalUnitType = NalUnitUtil.getH265NalUnitType(dataArray, nextNalUnitOffset);
int bytesWrittenPastNalUnit = limit - nextNalUnitOffset;
isKeyframe |= isRandomAccessPoint(nalUnitType);
// Output sample data for VCL NAL units.
if (isInVcl(nalUnitType)) {
if (isFirstSliceSegmentInPic(dataArray, nextNalUnitOffset)) {
if (foundFirstSample) {
if (isKeyframe && !hasOutputFormat && vps.isCompleted() && sps.isCompleted()
&& pps.isCompleted()) {
@ -138,7 +134,7 @@ import java.util.Collections;
foundFirstSample = true;
samplePosition = totalBytesWritten - bytesWrittenPastNalUnit;
sampleTimeUs = pesTimeUs;
isKeyframe = false;
isKeyframe = isRandomAccessPoint(nalUnitType);
}
// If the length to the start of the unit is negative then we wrote too many bytes to the
@ -325,7 +321,7 @@ import java.util.Collections;
} else {
int coefNum = Math.min(64, 1 << (4 + sizeId << 1));
if (sizeId > 1) {
// scaling_list_dc_coef_minus8[sizeId − 2][matrixId]
// scaling_list_dc_coef_minus8[sizeId - 2][matrixId]
bitArray.readSignedExpGolombCodedInt();
}
for (int i = 0; i < coefNum; i++) {
@ -336,17 +332,6 @@ import java.util.Collections;
}
}
/** Returns whether the NAL unit is a random access point. */
private static boolean isRandomAccessPoint(int nalUnitType) {
return nalUnitType == BLA_W_LP || nalUnitType == BLA_W_RADL || nalUnitType == BLA_N_LP
|| nalUnitType == IDR_W_RADL || nalUnitType == IDR_N_LP || nalUnitType == CRA_NUT;
}
/** Returns whether the NAL unit is in the video coding layer. */
private static boolean isInVcl(int nalUnitType) {
return nalUnitType <= VPS_NUT;
}
/**
* Reads the number of short term reference picture sets in a SPS as ue(v), then skips all of
* them. See H.265/HEVC (2014) 7.3.7.
@ -388,4 +373,30 @@ import java.util.Collections;
}
}
/**
* Returns whether the NAL unit is a random access point.
*/
private static boolean isRandomAccessPoint(int nalUnitType) {
return nalUnitType == BLA_W_LP || nalUnitType == BLA_W_RADL || nalUnitType == BLA_N_LP
|| nalUnitType == IDR_W_RADL || nalUnitType == IDR_N_LP || nalUnitType == CRA_NUT;
}
/**
* Returns whether the NAL unit in {@code data} starting at {@code offset} contains the first
* slice in a picture.
*
* @param data The data to read.
* @param offset The start offset of a NAL unit. Must lie between {@code -3} (inclusive) and
* {@code data.length - 3} (exclusive).
* @return Whether the NAL unit contains the first slice in a picture.
*/
public static boolean isFirstSliceSegmentInPic(byte[] data, int offset) {
int nalUnitType = NalUnitUtil.getH265NalUnitType(data, offset);
// Check the flag in NAL units that contain a slice_segment_layer_rbsp RBSP.
if ((nalUnitType <= RASL_R) || (nalUnitType >= BLA_W_LP && nalUnitType <= CRA_NUT)) {
return (data[offset + 5] & 0x80) != 0;
}
return false;
}
}