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Diffstat (limited to 'mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/util/NalUnitUtil.java')
| -rw-r--r-- | mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/util/NalUnitUtil.java | 519 |
1 files changed, 519 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/util/NalUnitUtil.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/util/NalUnitUtil.java new file mode 100644 index 0000000000..d7409daa66 --- /dev/null +++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/util/NalUnitUtil.java @@ -0,0 +1,519 @@ +/* + * Copyright (C) 2016 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.mozilla.thirdparty.com.google.android.exoplayer2.util; + +import java.nio.ByteBuffer; +import java.util.Arrays; + +/** + * Utility methods for handling H.264/AVC and H.265/HEVC NAL units. + */ +public final class NalUnitUtil { + + private static final String TAG = "NalUnitUtil"; + + /** + * Holds data parsed from a sequence parameter set NAL unit. + */ + public static final class SpsData { + + public final int profileIdc; + public final int constraintsFlagsAndReservedZero2Bits; + public final int levelIdc; + public final int seqParameterSetId; + public final int width; + public final int height; + public final float pixelWidthAspectRatio; + public final boolean separateColorPlaneFlag; + public final boolean frameMbsOnlyFlag; + public final int frameNumLength; + public final int picOrderCountType; + public final int picOrderCntLsbLength; + public final boolean deltaPicOrderAlwaysZeroFlag; + + public SpsData( + int profileIdc, + int constraintsFlagsAndReservedZero2Bits, + int levelIdc, + int seqParameterSetId, + int width, + int height, + float pixelWidthAspectRatio, + boolean separateColorPlaneFlag, + boolean frameMbsOnlyFlag, + int frameNumLength, + int picOrderCountType, + int picOrderCntLsbLength, + boolean deltaPicOrderAlwaysZeroFlag) { + this.profileIdc = profileIdc; + this.constraintsFlagsAndReservedZero2Bits = constraintsFlagsAndReservedZero2Bits; + this.levelIdc = levelIdc; + this.seqParameterSetId = seqParameterSetId; + this.width = width; + this.height = height; + this.pixelWidthAspectRatio = pixelWidthAspectRatio; + this.separateColorPlaneFlag = separateColorPlaneFlag; + this.frameMbsOnlyFlag = frameMbsOnlyFlag; + this.frameNumLength = frameNumLength; + this.picOrderCountType = picOrderCountType; + this.picOrderCntLsbLength = picOrderCntLsbLength; + this.deltaPicOrderAlwaysZeroFlag = deltaPicOrderAlwaysZeroFlag; + } + + } + + /** + * Holds data parsed from a picture parameter set NAL unit. + */ + public static final class PpsData { + + public final int picParameterSetId; + public final int seqParameterSetId; + public final boolean bottomFieldPicOrderInFramePresentFlag; + + public PpsData(int picParameterSetId, int seqParameterSetId, + boolean bottomFieldPicOrderInFramePresentFlag) { + this.picParameterSetId = picParameterSetId; + this.seqParameterSetId = seqParameterSetId; + this.bottomFieldPicOrderInFramePresentFlag = bottomFieldPicOrderInFramePresentFlag; + } + + } + + /** Four initial bytes that must prefix NAL units for decoding. */ + public static final byte[] NAL_START_CODE = new byte[] {0, 0, 0, 1}; + + /** Value for aspect_ratio_idc indicating an extended aspect ratio, in H.264 and H.265 SPSs. */ + public static final int EXTENDED_SAR = 0xFF; + /** Aspect ratios indexed by aspect_ratio_idc, in H.264 and H.265 SPSs. */ + public static final float[] ASPECT_RATIO_IDC_VALUES = new float[] { + 1f /* Unspecified. Assume square */, + 1f, + 12f / 11f, + 10f / 11f, + 16f / 11f, + 40f / 33f, + 24f / 11f, + 20f / 11f, + 32f / 11f, + 80f / 33f, + 18f / 11f, + 15f / 11f, + 64f / 33f, + 160f / 99f, + 4f / 3f, + 3f / 2f, + 2f + }; + + private static final int H264_NAL_UNIT_TYPE_SEI = 6; // Supplemental enhancement information + private static final int H264_NAL_UNIT_TYPE_SPS = 7; // Sequence parameter set + private static final int H265_NAL_UNIT_TYPE_PREFIX_SEI = 39; + + private static final Object scratchEscapePositionsLock = new Object(); + + /** + * Temporary store for positions of escape codes in {@link #unescapeStream(byte[], int)}. Guarded + * by {@link #scratchEscapePositionsLock}. + */ + private static int[] scratchEscapePositions = new int[10]; + + /** + * Unescapes {@code data} up to the specified limit, replacing occurrences of [0, 0, 3] with + * [0, 0]. The unescaped data is returned in-place, with the return value indicating its length. + * <p> + * Executions of this method are mutually exclusive, so it should not be called with very large + * buffers. + * + * @param data The data to unescape. + * @param limit The limit (exclusive) of the data to unescape. + * @return The length of the unescaped data. + */ + public static int unescapeStream(byte[] data, int limit) { + synchronized (scratchEscapePositionsLock) { + int position = 0; + int scratchEscapeCount = 0; + while (position < limit) { + position = findNextUnescapeIndex(data, position, limit); + if (position < limit) { + if (scratchEscapePositions.length <= scratchEscapeCount) { + // Grow scratchEscapePositions to hold a larger number of positions. + scratchEscapePositions = Arrays.copyOf(scratchEscapePositions, + scratchEscapePositions.length * 2); + } + scratchEscapePositions[scratchEscapeCount++] = position; + position += 3; + } + } + + int unescapedLength = limit - scratchEscapeCount; + int escapedPosition = 0; // The position being read from. + int unescapedPosition = 0; // The position being written to. + for (int i = 0; i < scratchEscapeCount; i++) { + int nextEscapePosition = scratchEscapePositions[i]; + int copyLength = nextEscapePosition - escapedPosition; + System.arraycopy(data, escapedPosition, data, unescapedPosition, copyLength); + unescapedPosition += copyLength; + data[unescapedPosition++] = 0; + data[unescapedPosition++] = 0; + escapedPosition += copyLength + 3; + } + + int remainingLength = unescapedLength - unescapedPosition; + System.arraycopy(data, escapedPosition, data, unescapedPosition, remainingLength); + return unescapedLength; + } + } + + /** + * Discards data from the buffer up to the first SPS, where {@code data.position()} is interpreted + * as the length of the buffer. + * <p> + * When the method returns, {@code data.position()} will contain the new length of the buffer. If + * the buffer is not empty it is guaranteed to start with an SPS. + * + * @param data Buffer containing start code delimited NAL units. + */ + public static void discardToSps(ByteBuffer data) { + int length = data.position(); + int consecutiveZeros = 0; + int offset = 0; + while (offset + 1 < length) { + int value = data.get(offset) & 0xFF; + if (consecutiveZeros == 3) { + if (value == 1 && (data.get(offset + 1) & 0x1F) == H264_NAL_UNIT_TYPE_SPS) { + // Copy from this NAL unit onwards to the start of the buffer. + ByteBuffer offsetData = data.duplicate(); + offsetData.position(offset - 3); + offsetData.limit(length); + data.position(0); + data.put(offsetData); + return; + } + } else if (value == 0) { + consecutiveZeros++; + } + if (value != 0) { + consecutiveZeros = 0; + } + offset++; + } + // Empty the buffer if the SPS NAL unit was not found. + data.clear(); + } + + /** + * Returns whether the NAL unit with the specified header contains supplemental enhancement + * information. + * + * @param mimeType The sample MIME type. + * @param nalUnitHeaderFirstByte The first byte of nal_unit(). + * @return Whether the NAL unit with the specified header is an SEI NAL unit. + */ + public static boolean isNalUnitSei(String mimeType, byte nalUnitHeaderFirstByte) { + return (MimeTypes.VIDEO_H264.equals(mimeType) + && (nalUnitHeaderFirstByte & 0x1F) == H264_NAL_UNIT_TYPE_SEI) + || (MimeTypes.VIDEO_H265.equals(mimeType) + && ((nalUnitHeaderFirstByte & 0x7E) >> 1) == H265_NAL_UNIT_TYPE_PREFIX_SEI); + } + + /** + * Returns the type of the NAL unit in {@code data} that starts at {@code offset}. + * + * @param data The data to search. + * @param offset The start offset of a NAL unit. Must lie between {@code -3} (inclusive) and + * {@code data.length - 3} (exclusive). + * @return The type of the unit. + */ + public static int getNalUnitType(byte[] data, int offset) { + return data[offset + 3] & 0x1F; + } + + /** + * Returns the type of the H.265 NAL unit in {@code data} that starts at {@code offset}. + * + * @param data The data to search. + * @param offset The start offset of a NAL unit. Must lie between {@code -3} (inclusive) and + * {@code data.length - 3} (exclusive). + * @return The type of the unit. + */ + public static int getH265NalUnitType(byte[] data, int offset) { + return (data[offset + 3] & 0x7E) >> 1; + } + + /** + * Parses an SPS NAL unit using the syntax defined in ITU-T Recommendation H.264 (2013) subsection + * 7.3.2.1.1. + * + * @param nalData A buffer containing escaped SPS data. + * @param nalOffset The offset of the NAL unit header in {@code nalData}. + * @param nalLimit The limit of the NAL unit in {@code nalData}. + * @return A parsed representation of the SPS data. + */ + public static SpsData parseSpsNalUnit(byte[] nalData, int nalOffset, int nalLimit) { + ParsableNalUnitBitArray data = new ParsableNalUnitBitArray(nalData, nalOffset, nalLimit); + data.skipBits(8); // nal_unit + int profileIdc = data.readBits(8); + int constraintsFlagsAndReservedZero2Bits = data.readBits(8); + int levelIdc = data.readBits(8); + int seqParameterSetId = data.readUnsignedExpGolombCodedInt(); + + int chromaFormatIdc = 1; // Default is 4:2:0 + boolean separateColorPlaneFlag = false; + if (profileIdc == 100 || profileIdc == 110 || profileIdc == 122 || profileIdc == 244 + || profileIdc == 44 || profileIdc == 83 || profileIdc == 86 || profileIdc == 118 + || profileIdc == 128 || profileIdc == 138) { + chromaFormatIdc = data.readUnsignedExpGolombCodedInt(); + if (chromaFormatIdc == 3) { + separateColorPlaneFlag = data.readBit(); + } + data.readUnsignedExpGolombCodedInt(); // bit_depth_luma_minus8 + data.readUnsignedExpGolombCodedInt(); // bit_depth_chroma_minus8 + data.skipBit(); // qpprime_y_zero_transform_bypass_flag + boolean seqScalingMatrixPresentFlag = data.readBit(); + if (seqScalingMatrixPresentFlag) { + int limit = (chromaFormatIdc != 3) ? 8 : 12; + for (int i = 0; i < limit; i++) { + boolean seqScalingListPresentFlag = data.readBit(); + if (seqScalingListPresentFlag) { + skipScalingList(data, i < 6 ? 16 : 64); + } + } + } + } + + int frameNumLength = data.readUnsignedExpGolombCodedInt() + 4; // log2_max_frame_num_minus4 + 4 + int picOrderCntType = data.readUnsignedExpGolombCodedInt(); + int picOrderCntLsbLength = 0; + boolean deltaPicOrderAlwaysZeroFlag = false; + if (picOrderCntType == 0) { + // log2_max_pic_order_cnt_lsb_minus4 + 4 + picOrderCntLsbLength = data.readUnsignedExpGolombCodedInt() + 4; + } else if (picOrderCntType == 1) { + deltaPicOrderAlwaysZeroFlag = data.readBit(); // delta_pic_order_always_zero_flag + data.readSignedExpGolombCodedInt(); // offset_for_non_ref_pic + data.readSignedExpGolombCodedInt(); // offset_for_top_to_bottom_field + long numRefFramesInPicOrderCntCycle = data.readUnsignedExpGolombCodedInt(); + for (int i = 0; i < numRefFramesInPicOrderCntCycle; i++) { + data.readUnsignedExpGolombCodedInt(); // offset_for_ref_frame[i] + } + } + data.readUnsignedExpGolombCodedInt(); // max_num_ref_frames + data.skipBit(); // gaps_in_frame_num_value_allowed_flag + + int picWidthInMbs = data.readUnsignedExpGolombCodedInt() + 1; + int picHeightInMapUnits = data.readUnsignedExpGolombCodedInt() + 1; + boolean frameMbsOnlyFlag = data.readBit(); + int frameHeightInMbs = (2 - (frameMbsOnlyFlag ? 1 : 0)) * picHeightInMapUnits; + if (!frameMbsOnlyFlag) { + data.skipBit(); // mb_adaptive_frame_field_flag + } + + data.skipBit(); // direct_8x8_inference_flag + int frameWidth = picWidthInMbs * 16; + int frameHeight = frameHeightInMbs * 16; + boolean frameCroppingFlag = data.readBit(); + if (frameCroppingFlag) { + int frameCropLeftOffset = data.readUnsignedExpGolombCodedInt(); + int frameCropRightOffset = data.readUnsignedExpGolombCodedInt(); + int frameCropTopOffset = data.readUnsignedExpGolombCodedInt(); + int frameCropBottomOffset = data.readUnsignedExpGolombCodedInt(); + int cropUnitX; + int cropUnitY; + if (chromaFormatIdc == 0) { + cropUnitX = 1; + cropUnitY = 2 - (frameMbsOnlyFlag ? 1 : 0); + } else { + int subWidthC = (chromaFormatIdc == 3) ? 1 : 2; + int subHeightC = (chromaFormatIdc == 1) ? 2 : 1; + cropUnitX = subWidthC; + cropUnitY = subHeightC * (2 - (frameMbsOnlyFlag ? 1 : 0)); + } + frameWidth -= (frameCropLeftOffset + frameCropRightOffset) * cropUnitX; + frameHeight -= (frameCropTopOffset + frameCropBottomOffset) * cropUnitY; + } + + float pixelWidthHeightRatio = 1; + boolean vuiParametersPresentFlag = data.readBit(); + if (vuiParametersPresentFlag) { + boolean aspectRatioInfoPresentFlag = data.readBit(); + if (aspectRatioInfoPresentFlag) { + int aspectRatioIdc = data.readBits(8); + if (aspectRatioIdc == NalUnitUtil.EXTENDED_SAR) { + int sarWidth = data.readBits(16); + int sarHeight = data.readBits(16); + if (sarWidth != 0 && sarHeight != 0) { + pixelWidthHeightRatio = (float) sarWidth / sarHeight; + } + } else if (aspectRatioIdc < NalUnitUtil.ASPECT_RATIO_IDC_VALUES.length) { + pixelWidthHeightRatio = NalUnitUtil.ASPECT_RATIO_IDC_VALUES[aspectRatioIdc]; + } else { + Log.w(TAG, "Unexpected aspect_ratio_idc value: " + aspectRatioIdc); + } + } + } + + return new SpsData( + profileIdc, + constraintsFlagsAndReservedZero2Bits, + levelIdc, + seqParameterSetId, + frameWidth, + frameHeight, + pixelWidthHeightRatio, + separateColorPlaneFlag, + frameMbsOnlyFlag, + frameNumLength, + picOrderCntType, + picOrderCntLsbLength, + deltaPicOrderAlwaysZeroFlag); + } + + /** + * Parses a PPS NAL unit using the syntax defined in ITU-T Recommendation H.264 (2013) subsection + * 7.3.2.2. + * + * @param nalData A buffer containing escaped PPS data. + * @param nalOffset The offset of the NAL unit header in {@code nalData}. + * @param nalLimit The limit of the NAL unit in {@code nalData}. + * @return A parsed representation of the PPS data. + */ + public static PpsData parsePpsNalUnit(byte[] nalData, int nalOffset, int nalLimit) { + ParsableNalUnitBitArray data = new ParsableNalUnitBitArray(nalData, nalOffset, nalLimit); + data.skipBits(8); // nal_unit + int picParameterSetId = data.readUnsignedExpGolombCodedInt(); + int seqParameterSetId = data.readUnsignedExpGolombCodedInt(); + data.skipBit(); // entropy_coding_mode_flag + boolean bottomFieldPicOrderInFramePresentFlag = data.readBit(); + return new PpsData(picParameterSetId, seqParameterSetId, bottomFieldPicOrderInFramePresentFlag); + } + + /** + * Finds the first NAL unit in {@code data}. + * <p> + * If {@code prefixFlags} is null then the first three bytes of a NAL unit must be entirely + * contained within the part of the array being searched in order for it to be found. + * <p> + * When {@code prefixFlags} is non-null, this method supports finding NAL units whose first four + * bytes span {@code data} arrays passed to successive calls. To use this feature, pass the same + * {@code prefixFlags} parameter to successive calls. State maintained in this parameter enables + * the detection of such NAL units. Note that when using this feature, the return value may be 3, + * 2 or 1 less than {@code startOffset}, to indicate a NAL unit starting 3, 2 or 1 bytes before + * the first byte in the current array. + * + * @param data The data to search. + * @param startOffset The offset (inclusive) in the data to start the search. + * @param endOffset The offset (exclusive) in the data to end the search. + * @param prefixFlags A boolean array whose first three elements are used to store the state + * required to detect NAL units where the NAL unit prefix spans array boundaries. The array + * must be at least 3 elements long. + * @return The offset of the NAL unit, or {@code endOffset} if a NAL unit was not found. + */ + public static int findNalUnit(byte[] data, int startOffset, int endOffset, + boolean[] prefixFlags) { + int length = endOffset - startOffset; + + Assertions.checkState(length >= 0); + if (length == 0) { + return endOffset; + } + + if (prefixFlags != null) { + if (prefixFlags[0]) { + clearPrefixFlags(prefixFlags); + return startOffset - 3; + } else if (length > 1 && prefixFlags[1] && data[startOffset] == 1) { + clearPrefixFlags(prefixFlags); + return startOffset - 2; + } else if (length > 2 && prefixFlags[2] && data[startOffset] == 0 + && data[startOffset + 1] == 1) { + clearPrefixFlags(prefixFlags); + return startOffset - 1; + } + } + + int limit = endOffset - 1; + // We're looking for the NAL unit start code prefix 0x000001. The value of i tracks the index of + // the third byte. + for (int i = startOffset + 2; i < limit; i += 3) { + if ((data[i] & 0xFE) != 0) { + // There isn't a NAL prefix here, or at the next two positions. Do nothing and let the + // loop advance the index by three. + } else if (data[i - 2] == 0 && data[i - 1] == 0 && data[i] == 1) { + if (prefixFlags != null) { + clearPrefixFlags(prefixFlags); + } + return i - 2; + } else { + // There isn't a NAL prefix here, but there might be at the next position. We should + // only skip forward by one. The loop will skip forward by three, so subtract two here. + i -= 2; + } + } + + if (prefixFlags != null) { + // True if the last three bytes in the data seen so far are {0,0,1}. + prefixFlags[0] = length > 2 + ? (data[endOffset - 3] == 0 && data[endOffset - 2] == 0 && data[endOffset - 1] == 1) + : length == 2 ? (prefixFlags[2] && data[endOffset - 2] == 0 && data[endOffset - 1] == 1) + : (prefixFlags[1] && data[endOffset - 1] == 1); + // True if the last two bytes in the data seen so far are {0,0}. + prefixFlags[1] = length > 1 ? data[endOffset - 2] == 0 && data[endOffset - 1] == 0 + : prefixFlags[2] && data[endOffset - 1] == 0; + // True if the last byte in the data seen so far is {0}. + prefixFlags[2] = data[endOffset - 1] == 0; + } + + return endOffset; + } + + /** + * Clears prefix flags, as used by {@link #findNalUnit(byte[], int, int, boolean[])}. + * + * @param prefixFlags The flags to clear. + */ + public static void clearPrefixFlags(boolean[] prefixFlags) { + prefixFlags[0] = false; + prefixFlags[1] = false; + prefixFlags[2] = false; + } + + private static int findNextUnescapeIndex(byte[] bytes, int offset, int limit) { + for (int i = offset; i < limit - 2; i++) { + if (bytes[i] == 0x00 && bytes[i + 1] == 0x00 && bytes[i + 2] == 0x03) { + return i; + } + } + return limit; + } + + private static void skipScalingList(ParsableNalUnitBitArray bitArray, int size) { + int lastScale = 8; + int nextScale = 8; + for (int i = 0; i < size; i++) { + if (nextScale != 0) { + int deltaScale = bitArray.readSignedExpGolombCodedInt(); + nextScale = (lastScale + deltaScale + 256) % 256; + } + lastScale = (nextScale == 0) ? lastScale : nextScale; + } + } + + private NalUnitUtil() { + // Prevent instantiation. + } + +} |