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Support for Large CodecSpecificData in ESDS box

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Some external media files have CodecSpecificData greater than 128 bytes. Currently, that size
isn't fitting in one byte. Hence, added support to store large CodecSpecificDataSize, as per
ISO standard, by extending to more than one byte as required.

PiperOrigin-RevId: 650972472
This commit is contained in:
Googler 2024-07-10 05:13:18 -07:00 committed by Copybara-Service
parent 9d4e43cf55
commit cf90d2624d
1 changed files with 35 additions and 17 deletions
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52
libraries/muxer/src/main/java/androidx/media3/muxer/Boxes.java
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@ -39,6 +39,7 @@ import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.common.primitives.Bytes;
import java.nio.ByteBuffer;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
@ -1343,37 +1344,37 @@ import java.util.List;
ByteBuffer csd0ByteBuffer = ByteBuffer.wrap(csd0);
int peakBitrate = format.peakBitrate;
int averageBitrate = format.averageBitrate;
int csd0Size = csd0ByteBuffer.limit();
ByteBuffer dsiSizeBuffer = getSizeBuffer(csd0Size);
ByteBuffer dcdSizeBuffer = getSizeBuffer(csd0Size + dsiSizeBuffer.remaining() + 14);
ByteBuffer esdSizeBuffer =
getSizeBuffer(csd0Size + dsiSizeBuffer.remaining() + dcdSizeBuffer.remaining() + 21);
ByteBuffer contents = ByteBuffer.allocate(csd0Size + MAX_FIXED_LEAF_BOX_SIZE);
contents.putInt(0x0); // version and flags.
contents.putInt(0x00); // Version and flags.
contents.put((byte) 0x03); // ES_DescrTag
// We're normally using a variable-length encoding for the length of various sub-packages (esds
// etc.), in a nested way, so outer lengths need to account for variable-length inner lengths
// too (to save ~10 bytes per video file). Meanwhile, AAC codec-specific
// data is typically just 2 bytes, so every length actually fits into a byte. Here, we're just
// skipping the entire complex story by asserting that we won't ever need variable-length sizes.
checkArgument(csd0Size + 21 < 127, "CSD too long; we might need variable-length encoding?");
contents.put(esdSizeBuffer);
contents.put((byte) (23 + csd0Size));
contents.putShort((short) 0x0000); // ES_ID
contents.put((byte) 0x00);
contents.putShort((short) 0x0000); // First 16 bits of ES_ID.
contents.put((byte) 0x00); // Last 8 bits of ES_ID.
contents.put((byte) 0x04); // DecoderConfigDescrTag
contents.put((byte) (15 + csd0Size));
contents.put((byte) 0x40); // objectTypeIndication
contents.put((byte) 0x15); // streamType AudioStream
contents.put(dcdSizeBuffer);
contents.putShort((short) 0x03);
contents.put((byte) 0x00); // 24-bit buffer size (0x300)
contents.put((byte) 0x40); // objectTypeIndication
// streamType (6 bits) | upStream (1 bit) | reserved = 1 (1 bit)
contents.put((byte) ((0x05 << 2) | 0x01)); // streamType AudioStream
contents.putShort((short) 0x03); // First 16 bits of buffer size (0x300).
contents.put((byte) 0x00); // Last 8 bits of buffer size (0x300).
contents.putInt(peakBitrate != Format.NO_VALUE ? peakBitrate : 0);
contents.putInt(averageBitrate != Format.NO_VALUE ? averageBitrate : 0);
contents.put((byte) 0x05); // DecoderSpecificInfoTag
contents.put((byte) csd0Size);
contents.put(dsiSizeBuffer);
contents.put(csd0ByteBuffer);
csd0ByteBuffer.rewind();
@ -1385,6 +1386,23 @@ import java.util.List;
return BoxUtils.wrapIntoBox("esds", contents);
}
private static ByteBuffer getSizeBuffer(int length) {
int prefix = 0;
ArrayDeque<Byte> esdsSizeBytes = new ArrayDeque<>();
do {
esdsSizeBytes.push((byte) (prefix | (length & 0x7F)));
length >>= 7;
prefix = 0x80;
} while (length > 0);
ByteBuffer sizeBuffer = ByteBuffer.allocate(esdsSizeBytes.size());
while (!esdsSizeBytes.isEmpty()) {
sizeBuffer.put(esdsSizeBytes.removeFirst());
}
sizeBuffer.flip();
return sizeBuffer;
}
/** Returns the audio damr box. */
private static ByteBuffer damrBox(short mode) {