diff options
Diffstat (limited to 'mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/mp4/Sniffer.java')
| -rw-r--r-- | mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/mp4/Sniffer.java | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/mp4/Sniffer.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/mp4/Sniffer.java new file mode 100644 index 0000000000..d58c2f06eb --- /dev/null +++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/mp4/Sniffer.java @@ -0,0 +1,201 @@ +/* + * 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.extractor.mp4; + +import org.mozilla.thirdparty.com.google.android.exoplayer2.C; +import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.ExtractorInput; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ParsableByteArray; +import java.io.IOException; + +/** + * Provides methods that peek data from an {@link ExtractorInput} and return whether the input + * appears to be in MP4 format. + */ +/* package */ final class Sniffer { + + /** The maximum number of bytes to peek when sniffing. */ + private static final int SEARCH_LENGTH = 4 * 1024; + + private static final int[] COMPATIBLE_BRANDS = + new int[] { + 0x69736f6d, // isom + 0x69736f32, // iso2 + 0x69736f33, // iso3 + 0x69736f34, // iso4 + 0x69736f35, // iso5 + 0x69736f36, // iso6 + 0x61766331, // avc1 + 0x68766331, // hvc1 + 0x68657631, // hev1 + 0x61763031, // av01 + 0x6d703431, // mp41 + 0x6d703432, // mp42 + 0x33673261, // 3g2a + 0x33673262, // 3g2b + 0x33677236, // 3gr6 + 0x33677336, // 3gs6 + 0x33676536, // 3ge6 + 0x33676736, // 3gg6 + 0x4d345620, // M4V[space] + 0x4d344120, // M4A[space] + 0x66347620, // f4v[space] + 0x6b646469, // kddi + 0x4d345650, // M4VP + 0x71742020, // qt[space][space], Apple QuickTime + 0x4d534e56, // MSNV, Sony PSP + 0x64627931, // dby1, Dolby Vision + }; + + /** + * Returns whether data peeked from the current position in {@code input} is consistent with the + * input being a fragmented MP4 file. + * + * @param input The extractor input from which to peek data. The peek position will be modified. + * @return Whether the input appears to be in the fragmented MP4 format. + * @throws IOException If an error occurs reading from the input. + * @throws InterruptedException If the thread has been interrupted. + */ + public static boolean sniffFragmented(ExtractorInput input) + throws IOException, InterruptedException { + return sniffInternal(input, true); + } + + /** + * Returns whether data peeked from the current position in {@code input} is consistent with the + * input being an unfragmented MP4 file. + * + * @param input The extractor input from which to peek data. The peek position will be modified. + * @return Whether the input appears to be in the unfragmented MP4 format. + * @throws IOException If an error occurs reading from the input. + * @throws InterruptedException If the thread has been interrupted. + */ + public static boolean sniffUnfragmented(ExtractorInput input) + throws IOException, InterruptedException { + return sniffInternal(input, false); + } + + private static boolean sniffInternal(ExtractorInput input, boolean fragmented) + throws IOException, InterruptedException { + long inputLength = input.getLength(); + int bytesToSearch = (int) (inputLength == C.LENGTH_UNSET || inputLength > SEARCH_LENGTH + ? SEARCH_LENGTH : inputLength); + + ParsableByteArray buffer = new ParsableByteArray(64); + int bytesSearched = 0; + boolean foundGoodFileType = false; + boolean isFragmented = false; + while (bytesSearched < bytesToSearch) { + // Read an atom header. + int headerSize = Atom.HEADER_SIZE; + buffer.reset(headerSize); + input.peekFully(buffer.data, 0, headerSize); + long atomSize = buffer.readUnsignedInt(); + int atomType = buffer.readInt(); + if (atomSize == Atom.DEFINES_LARGE_SIZE) { + // Read the large atom size. + headerSize = Atom.LONG_HEADER_SIZE; + input.peekFully(buffer.data, Atom.HEADER_SIZE, Atom.LONG_HEADER_SIZE - Atom.HEADER_SIZE); + buffer.setLimit(Atom.LONG_HEADER_SIZE); + atomSize = buffer.readLong(); + } else if (atomSize == Atom.EXTENDS_TO_END_SIZE) { + // The atom extends to the end of the file. + long fileEndPosition = input.getLength(); + if (fileEndPosition != C.LENGTH_UNSET) { + atomSize = fileEndPosition - input.getPeekPosition() + headerSize; + } + } + + if (atomSize < headerSize) { + // The file is invalid because the atom size is too small for its header. + return false; + } + bytesSearched += headerSize; + + if (atomType == Atom.TYPE_moov) { + // We have seen the moov atom. We increase the search size to make sure we don't miss an + // mvex atom because the moov's size exceeds the search length. + bytesToSearch += (int) atomSize; + if (inputLength != C.LENGTH_UNSET && bytesToSearch > inputLength) { + // Make sure we don't exceed the file size. + bytesToSearch = (int) inputLength; + } + // Check for an mvex atom inside the moov atom to identify whether the file is fragmented. + continue; + } + + if (atomType == Atom.TYPE_moof || atomType == Atom.TYPE_mvex) { + // The movie is fragmented. Stop searching as we must have read any ftyp atom already. + isFragmented = true; + break; + } + + if (bytesSearched + atomSize - headerSize >= bytesToSearch) { + // Stop searching as peeking this atom would exceed the search limit. + break; + } + + int atomDataSize = (int) (atomSize - headerSize); + bytesSearched += atomDataSize; + if (atomType == Atom.TYPE_ftyp) { + // Parse the atom and check the file type/brand is compatible with the extractors. + if (atomDataSize < 8) { + return false; + } + buffer.reset(atomDataSize); + input.peekFully(buffer.data, 0, atomDataSize); + int brandsCount = atomDataSize / 4; + for (int i = 0; i < brandsCount; i++) { + if (i == 1) { + // This index refers to the minorVersion, not a brand, so skip it. + buffer.skipBytes(4); + } else if (isCompatibleBrand(buffer.readInt())) { + foundGoodFileType = true; + break; + } + } + if (!foundGoodFileType) { + // The types were not compatible and there is only one ftyp atom, so reject the file. + return false; + } + } else if (atomDataSize != 0) { + // Skip the atom. + input.advancePeekPosition(atomDataSize); + } + } + return foundGoodFileType && fragmented == isFragmented; + } + + /** + * Returns whether {@code brand} is an ftyp atom brand that is compatible with the MP4 extractors. + */ + private static boolean isCompatibleBrand(int brand) { + // Accept all brands starting '3gp'. + if (brand >>> 8 == 0x00336770) { + return true; + } + for (int compatibleBrand : COMPATIBLE_BRANDS) { + if (compatibleBrand == brand) { + return true; + } + } + return false; + } + + private Sniffer() { + // Prevent instantiation. + } + +} |