From 4ded7e588d3699523d42300ff198dd3ec7461f95 Mon Sep 17 00:00:00 2001 From: Haixia Shi Date: Wed, 27 Sep 2023 10:34:00 -0700 Subject: [PATCH] Add AV1 color space parsing in MP4 atom parser This adds av1C parsing based on the AV1 bitstream specification: https://aomediacodec.github.io/av1-spec/av1-spec.pdf This is needed to have correct color space when using hardware AV1 decoder. --- .../media3/extractor/mp4/AtomParsers.java | 138 ++++++++++++++++++ 1 file changed, 138 insertions(+) diff --git a/libraries/extractor/src/main/java/androidx/media3/extractor/mp4/AtomParsers.java b/libraries/extractor/src/main/java/androidx/media3/extractor/mp4/AtomParsers.java index 3d29f06b8f..ba20cab216 100644 --- a/libraries/extractor/src/main/java/androidx/media3/extractor/mp4/AtomParsers.java +++ b/libraries/extractor/src/main/java/androidx/media3/extractor/mp4/AtomParsers.java @@ -19,6 +19,7 @@ import static androidx.media3.common.MimeTypes.getMimeTypeFromMp4ObjectType; import static androidx.media3.common.util.Assertions.checkNotNull; import static androidx.media3.common.util.Util.castNonNull; import static java.lang.Math.max; +import static java.lang.Math.min; import android.util.Pair; import androidx.annotation.Nullable; @@ -1091,6 +1092,133 @@ import java.util.List; .build(); } + // Helper class for parsing syntax elements from AV1 bitstream. + // Bitstream specification: https://aomediacodec.github.io/av1-spec/av1-spec.pdf + private static final class Av1BitstreamParser { + private static final String TAG = "Av1BitstreamParser"; + + private ParsableByteArray data; + private int bitCount; + private int currentByte; + + public int colorDescriptionPresentFlag; + public int colorPrimaries; + public int transferCharacteristics; + public int matrixCoefficients; + public int colorRange; + + public Av1BitstreamParser(ParsableByteArray data) { + this.data = data; + } + + private int f(int length) { + // 4.10.2. f(n): Unsigned n-bit number appearing directly in the bitstream. + // The bits are read from high to low order. + int result = 0; + while (length > 0) { + if (bitCount == 0) { + currentByte = data.readUnsignedByte(); + bitCount = 8; + } + int newBitCount = min(length, bitCount); + bitCount -= newBitCount; + length -= newBitCount; + result = (result << newBitCount) | + ((currentByte >> bitCount) & ((1 << newBitCount) - 1)); + } + return result; + } + + public boolean parseSequenceHeader() { + // 5.3.1. General OBU syntax + f(1); // obu_forbidden_bit + int obuType = f(4); // obu_type + if (obuType != 1) { // obu_type != OBU_SEQUENCE_HEADER + Log.e(TAG, "Unsupported obu_type: " + obuType); + return false; + } else if (f(1) != 0) { // obu_extension_flag + Log.e(TAG, "Unsupported obu_extension_flag"); + return false; + } + int obuHasSizeField = f(1); // obu_has_size_field + f(1); // obu_reserved_1bit + if (obuHasSizeField == 1 && f(8) > 127) { // obu_size + Log.e(TAG, "Excessive obu_size"); + return false; + } + // 5.5.1. General sequence header OBU syntax + int seqProfile = f(3); // seq_profile + f(1); // still_picture + if (f(1) != 0) { // reduced_still_picture_header + Log.e(TAG, "Unsupported reduced_still_picture_header"); + return false; + } else if (f(1) != 0) { // timing_info_present_flag + Log.e(TAG, "Unsupported timing_info_present_flag"); + return false; + } else if (f(1) != 0) { // initial_display_delay_present_flag + Log.e(TAG, "Unsupported initial_display_delay_present_flag"); + return false; + } + int operatingPointsCntMinus1 = f(5); // operating_points_cnt_minus_1 + for (int i = 0; i <= operatingPointsCntMinus1; i++) { + f(12); // operating_point_idc[i] + int seqLevelIdx = f(5); // seq_level_idx[i] + if (seqLevelIdx > 7) { + f(1); // seq_tier[i] + } + } + int frameWidthBitsMinus1 = f(4); // frame_width_bits_minus_1 + int frameHeightBitsMinus1 = f(4); // frame_height_bits_minus_1 + f(frameWidthBitsMinus1 + 1); // max_frame_width_minus_1 + f(frameHeightBitsMinus1 + 1); // max_frame_height_minus_1 + if (f(1) == 1) { // frame_id_numbers_present_flag + f(7); // delta_frame_id_length_minus_2, additional_frame_id_length_minus_1 + } + f(7); // use_128x128_superblock...enable_dual_filter: 7 flags + int enableOrderHint = f(1); // enable_order_hint + if (enableOrderHint == 1) { + f(2); // enable_jnt_comp, enable_ref_frame_mvs + } + int seqForceScreenContentTools = 2; // SELECT_SCREEN_CONTENT_TOOLS + if (f(1) == 0) { // seq_choose_screen_content_tools + seqForceScreenContentTools = f(1); // seq_force_screen_content_tools + } + if (seqForceScreenContentTools > 0) { + if (f(1) == 0) { // seq_choose_integer_mv + f(1); // seq_force_integer_mv + } + } + if (enableOrderHint == 1) { + f(3); // order_hint_bits_minus_1 + } + f(3); // enable_superres, enable_cdef, enable_restoration + // 5.5.2. Color config syntax + int highBitdepth = f(1); // high_bitdepth + if (seqProfile == 2 && highBitdepth == 1) { + f(1); // twelve_bit + } + int monoChrome = 0; + if (seqProfile != 1) { + monoChrome = f(1); // mono_chrome + } + colorDescriptionPresentFlag = f(1); // color_description_present_flag + if (colorDescriptionPresentFlag == 1) { + colorPrimaries = f(8); // color_primaries + transferCharacteristics = f(8); // transfer_characteristics + matrixCoefficients = f(8); // matrix_coefficients + if (monoChrome == 0 + && colorPrimaries == 1 // CP_BT_709 + && transferCharacteristics == 13 // TC_SRGB + && matrixCoefficients == 0) { // MC_IDENTITY + colorRange = 1; + } else { + colorRange = f(1); // color_range + } + } + return true; + } + } + // hdrStaticInfo is allocated using allocate() in allocateHdrStaticInfo(). @SuppressWarnings("ByteBufferBackingArray") private static void parseVideoSampleEntry( @@ -1237,6 +1365,16 @@ import java.util.List; bitdepthLuma = highBitdepth ? 10 : 8; } bitdepthChroma = bitdepthLuma; + // See av1C atom syntax: https://aomediacodec.github.io/av1-isobmff/#av1codecconfigurationbox-syntax + parent.skipBytes(4); // skip to configOBUs[] + Av1BitstreamParser parser = new Av1BitstreamParser(parent); + if (parser.parseSequenceHeader() && parser.colorDescriptionPresentFlag == 1) { + colorSpace = ColorInfo.isoColorPrimariesToColorSpace(parser.colorPrimaries); + colorTransfer = ColorInfo.isoTransferCharacteristicsToColorTransfer( + parser.transferCharacteristics + ); + colorRange = (parser.colorRange == 1) ? C.COLOR_RANGE_FULL : C.COLOR_RANGE_LIMITED; + } } else if (childAtomType == Atom.TYPE_clli) { if (hdrStaticInfo == null) { hdrStaticInfo = allocateHdrStaticInfo();