/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* vim:set ts=2 sw=2 sts=2 tw=80 et cindent: */ /* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ #include "nsMediaSniffer.h" #include "nsIHttpChannel.h" #include "nsString.h" #include "nsMimeTypes.h" #include "mozilla/ArrayUtils.h" #include "mozilla/ModuleUtils.h" #include "mp3sniff.h" #include "nestegg/nestegg.h" #include "FlacDemuxer.h" #include "nsIClassInfoImpl.h" #include <algorithm> // The minimum number of bytes that are needed to attempt to sniff an mp4 file. static const unsigned MP4_MIN_BYTES_COUNT = 12; // The maximum number of bytes to consider when attempting to sniff a file. static const uint32_t MAX_BYTES_SNIFFED = 512; // The maximum number of bytes to consider when attempting to sniff for a mp3 // bitstream. // This is 320kbps * 144 / 32kHz + 1 padding byte + 4 bytes of capture pattern. static const uint32_t MAX_BYTES_SNIFFED_MP3 = 320 * 144 / 32 + 1 + 4; NS_IMPL_ISUPPORTS(nsMediaSniffer, nsIContentSniffer) nsMediaSnifferEntry nsMediaSniffer::sSnifferEntries[] = { // The string OggS, followed by the null byte. PATTERN_ENTRY("\xFF\xFF\xFF\xFF\xFF", "OggS", APPLICATION_OGG), // The string RIFF, followed by four bytes, followed by the string WAVE PATTERN_ENTRY("\xFF\xFF\xFF\xFF\x00\x00\x00\x00\xFF\xFF\xFF\xFF", "RIFF\x00\x00\x00\x00WAVE", AUDIO_WAV), // mp3 with ID3 tags, the string "ID3". PATTERN_ENTRY("\xFF\xFF\xFF", "ID3", AUDIO_MP3), // FLAC with standard header PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "fLaC", AUDIO_FLAC) }; // For a complete list of file types, see http://www.ftyps.com/index.html nsMediaSnifferEntry sFtypEntries[] = { PATTERN_ENTRY("\xFF\xFF\xFF", "mp4", VIDEO_MP4), // Could be mp41 or mp42. PATTERN_ENTRY("\xFF\xFF\xFF", "avc", VIDEO_MP4), // Could be avc1, avc2, ... PATTERN_ENTRY("\xFF\xFF\xFF", "3gp", VIDEO_3GPP), // Could be 3gp4, 3gp5, ... PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "M4A ", AUDIO_MP4), PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "M4P ", AUDIO_MP4), PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "qt ", VIDEO_QUICKTIME), PATTERN_ENTRY("\xFF\xFF\xFF", "iso", VIDEO_MP4), // Could be isom or iso2. PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "mmp4", VIDEO_MP4), }; static bool MatchesBrands(const uint8_t aData[4], nsACString& aSniffedType) { for (size_t i = 0; i < mozilla::ArrayLength(sFtypEntries); ++i) { const auto& currentEntry = sFtypEntries[i]; bool matched = true; MOZ_ASSERT(currentEntry.mLength <= 4, "Pattern is too large to match brand strings."); for (uint32_t j = 0; j < currentEntry.mLength; ++j) { if ((currentEntry.mMask[j] & aData[j]) != currentEntry.mPattern[j]) { matched = false; break; } } if (matched) { aSniffedType.AssignASCII(currentEntry.mContentType); return true; } } return false; } // This function implements sniffing algorithm for MP4 family file types, // including MP4 (described at http://mimesniff.spec.whatwg.org/#signature-for-mp4), // M4A (Apple iTunes audio), and 3GPP. static bool MatchesMP4(const uint8_t* aData, const uint32_t aLength, nsACString& aSniffedType) { if (aLength <= MP4_MIN_BYTES_COUNT) { return false; } // Conversion from big endian to host byte order. uint32_t boxSize = (uint32_t)(aData[3] | aData[2] << 8 | aData[1] << 16 | aData[0] << 24); // Boxsize should be evenly divisible by 4. if (boxSize % 4 || aLength < boxSize) { return false; } // The string "ftyp". if (aData[4] != 0x66 || aData[5] != 0x74 || aData[6] != 0x79 || aData[7] != 0x70) { return false; } if (MatchesBrands(&aData[8], aSniffedType)) { return true; } // Skip minor_version (bytes 12-15). uint32_t bytesRead = 16; while (bytesRead < boxSize) { if (MatchesBrands(&aData[bytesRead], aSniffedType)) { return true; } bytesRead += 4; } return false; } static bool MatchesWebM(const uint8_t* aData, const uint32_t aLength) { return nestegg_sniff((uint8_t*)aData, aLength) ? true : false; } // This function implements mp3 sniffing based on parsing // packet headers and looking for expected boundaries. static bool MatchesMP3(const uint8_t* aData, const uint32_t aLength) { return mp3_sniff(aData, (long)aLength); } static bool MatchesFLAC(const uint8_t* aData, const uint32_t aLength) { return mozilla::FlacDemuxer::FlacSniffer(aData, aLength); } NS_IMETHODIMP nsMediaSniffer::GetMIMETypeFromContent(nsIRequest* aRequest, const uint8_t* aData, const uint32_t aLength, nsACString& aSniffedType) { nsCOMPtr<nsIChannel> channel = do_QueryInterface(aRequest); if (channel) { nsLoadFlags loadFlags = 0; channel->GetLoadFlags(&loadFlags); if (!(loadFlags & nsIChannel::LOAD_MEDIA_SNIFFER_OVERRIDES_CONTENT_TYPE)) { // For media, we want to sniff only if the Content-Type is unknown, or if it // is application/octet-stream. nsAutoCString contentType; nsresult rv = channel->GetContentType(contentType); NS_ENSURE_SUCCESS(rv, rv); if (!contentType.IsEmpty() && !contentType.EqualsLiteral(APPLICATION_OCTET_STREAM) && !contentType.EqualsLiteral(UNKNOWN_CONTENT_TYPE)) { return NS_ERROR_NOT_AVAILABLE; } } } const uint32_t clampedLength = std::min(aLength, MAX_BYTES_SNIFFED); for (size_t i = 0; i < mozilla::ArrayLength(sSnifferEntries); ++i) { const nsMediaSnifferEntry& currentEntry = sSnifferEntries[i]; if (clampedLength < currentEntry.mLength || currentEntry.mLength == 0) { continue; } bool matched = true; for (uint32_t j = 0; j < currentEntry.mLength; ++j) { if ((currentEntry.mMask[j] & aData[j]) != currentEntry.mPattern[j]) { matched = false; break; } } if (matched) { aSniffedType.AssignASCII(currentEntry.mContentType); return NS_OK; } } if (MatchesMP4(aData, clampedLength, aSniffedType)) { return NS_OK; } if (MatchesWebM(aData, clampedLength)) { aSniffedType.AssignLiteral(VIDEO_WEBM); return NS_OK; } // Bug 950023: 512 bytes are often not enough to sniff for mp3. if (MatchesMP3(aData, std::min(aLength, MAX_BYTES_SNIFFED_MP3))) { aSniffedType.AssignLiteral(AUDIO_MP3); return NS_OK; } // Flac frames are generally big, often in excess of 24kB. // Using a size of MAX_BYTES_SNIFFED effectively means that we will only // recognize flac content if it starts with a frame. if (MatchesFLAC(aData, clampedLength)) { aSniffedType.AssignLiteral(AUDIO_FLAC); return NS_OK; } // Could not sniff the media type, we are required to set it to // application/octet-stream. aSniffedType.AssignLiteral(APPLICATION_OCTET_STREAM); return NS_ERROR_NOT_AVAILABLE; }