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Changes based on internal comments

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This commit is contained in:
Rohit Singh 2024-04-12 15:01:27 +01:00
parent ae77333d0f
commit 6811b8394b
2 changed files with 80 additions and 98 deletions
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11
libraries/common/src/main/java/androidx/media3/common/util/ParsableBitArray.java
View file

@ -17,7 +17,6 @@ package androidx.media3.common.util;
import static java.lang.Math.min;
import androidx.media3.common.C;
import com.google.common.base.Charsets;
import com.google.errorprone.annotations.CheckReturnValue;
import java.nio.charset.Charset;
@ -249,16 +248,6 @@ public final class ParsableBitArray {
assertValidOffset();
}
/**
* Whether the position is byte-aligned. A bit position is considered byte-aligned if the number
* of bits left in the current position is a multiple of {@link C#BITS_PER_BYTE}.
*
* @return {@code true} if the position is byte-aligned, {@code false} otherwise.
*/
public boolean isByteAligned() {
return bitsLeft() % C.BITS_PER_BYTE == 0;
}
/**
* Reads the next {@code length} bytes into {@code buffer}. Must only be called when the position
* is byte aligned.

167
libraries/extractor/src/main/java/androidx/media3/extractor/MpeghUtil.java
View file

@ -41,10 +41,8 @@ public final class MpeghUtil {
public static final int MAX_MHAS_PACKET_HEADER_SIZE = 15;
/**
* Returns whether a given integer matches an MHAS sync word. See ISO_IEC_23008-3;2022, 14.4.4.
*
* @param word An integer.
* @return Whether a given integer matches an MHAS sync word.
* Returns whether the lower 3 bytes of the given integer matches an MHAS sync word. See
* ISO_IEC_23008-3;2022, 14.4.4.
*/
public static boolean isSyncWord(int word) {
return (word & 0xFFFFFF) == MHAS_SYNC_WORD;
@ -92,82 +90,6 @@ public final class MpeghUtil {
return new MhasPacketHeader(packetType, packetLabel, packetLength, headerLength);
}
/**
* Obtains the sampling rate of the current MPEG-H frame. See ISO_IEC_23003-3;2020, 5.2, Table 7.
* The reading position of {@code data} will be modified.
*
* @param data The data to parse, positioned at the start of the fields to obtain the sampling
* rate from.
* @return The sampling frequency.
* @throws ParserException if sampling frequency could not be obtained.
*/
private static int getSamplingFrequency(ParsableBitArray data) throws ParserException {
int samplingFrequencyIndex = data.readBits(5);
if (samplingFrequencyIndex == 0x1F) {
return data.readBits(24);
}
// See ISO_IEC_23003-3;2020, 6.1.1.1, Table 72.
switch (samplingFrequencyIndex) {
case 0:
return 96_000;
case 1:
return 88_200;
case 2:
return 64_000;
case 3:
return 48_000;
case 4:
return 44_100;
case 5:
return 32_000;
case 6:
return 24_000;
case 7:
return 22_050;
case 8:
return 16_000;
case 9:
return 12_000;
case 10:
return 11_025;
case 11:
return 8_000;
case 12:
return 7350;
case 15:
return 57_600;
case 16:
return 51_200;
case 17:
return 40_000;
case 18:
return 38_400;
case 19:
return 34_150;
case 20:
return 28_800;
case 21:
return 25_600;
case 22:
return 20_000;
case 23:
return 19_200;
case 24:
return 17_075;
case 25:
return 14_400;
case 26:
return 12_800;
case 27:
return 9_600;
default:
throw ParserException.createForUnsupportedContainerFeature(
"Unsupported sampling rate index " + samplingFrequencyIndex);
}
}
/**
* Obtains the output frame length of the current MPEG-H frame. See ISO_IEC_23003-3;2020, 6.1.1.1,
* Table 75.
@ -289,14 +211,9 @@ public final class MpeghUtil {
int profileLevelIndication = data.readBits(8);
int usacSamplingFrequency = getSamplingFrequency(data);
if (usacSamplingFrequency <= 0) {
throw ParserException.createForUnsupportedContainerFeature(
"Unsupported sampling frequency " + usacSamplingFrequency);
}
int coreSbrFrameLengthIndex = data.readBits(3);
int outputFrameLength = getOutputFrameLength(/* index= */ coreSbrFrameLengthIndex);
int sbrRatioIndex = getSbrRatioIndex(/* index= */ coreSbrFrameLengthIndex);
int outputFrameLength = getOutputFrameLength(coreSbrFrameLengthIndex);
int sbrRatioIndex = getSbrRatioIndex(coreSbrFrameLengthIndex);
data.skipBits(2); // cfg_reserved(1), receiverDelayCompensation(1)
@ -334,6 +251,82 @@ public final class MpeghUtil {
profileLevelIndication, samplingFrequency, standardFrameSamples, compatibleProfileLevelSet);
}
/**
* Obtains the sampling rate of the current MPEG-H frame. See ISO_IEC_23003-3;2020, 5.2, Table 7.
* The reading position of {@code data} will be modified.
*
* @param data The data to parse, positioned at the start of the fields to obtain the sampling
* rate from.
* @return The sampling frequency.
* @throws ParserException if sampling frequency could not be obtained.
*/
private static int getSamplingFrequency(ParsableBitArray data) throws ParserException {
int samplingFrequencyIndex = data.readBits(5);
if (samplingFrequencyIndex == 0x1F) {
return data.readBits(24);
}
// See ISO_IEC_23003-3;2020, 6.1.1.1, Table 72.
switch (samplingFrequencyIndex) {
case 0:
return 96_000;
case 1:
return 88_200;
case 2:
return 64_000;
case 3:
return 48_000;
case 4:
return 44_100;
case 5:
return 32_000;
case 6:
return 24_000;
case 7:
return 22_050;
case 8:
return 16_000;
case 9:
return 12_000;
case 10:
return 11_025;
case 11:
return 8_000;
case 12:
return 7350;
case 15:
return 57_600;
case 16:
return 51_200;
case 17:
return 40_000;
case 18:
return 38_400;
case 19:
return 34_150;
case 20:
return 28_800;
case 21:
return 25_600;
case 22:
return 20_000;
case 23:
return 19_200;
case 24:
return 17_075;
case 25:
return 14_400;
case 26:
return 12_800;
case 27:
return 9_600;
default:
throw ParserException.createForUnsupportedContainerFeature(
"Unsupported sampling rate index " + samplingFrequencyIndex);
}
}
/**
* Obtains the number of truncated samples of the AudioTruncationInfo from an MPEG-H bit stream.
* See ISO_IEC_23008-3;2022, 14.2.2, Table 225. The reading position of {@code data} will be