1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/toolkit/components/mediasniffer/nsMediaSniffer.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,159 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* vim:set ts=2 sw=2 sts=2 tw=80 et cindent: */
1.6 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#include "nsMediaSniffer.h"
1.11 +#include "nsIHttpChannel.h"
1.12 +#include "nsString.h"
1.13 +#include "nsMimeTypes.h"
1.14 +#include "mozilla/ArrayUtils.h"
1.15 +#include "mozilla/ModuleUtils.h"
1.16 +#include "mp3sniff.h"
1.17 +#ifdef MOZ_WEBM
1.18 +#include "nestegg/nestegg.h"
1.19 +#endif
1.20 +
1.21 +#include "nsIClassInfoImpl.h"
1.22 +#include <algorithm>
1.23 +
1.24 +// The minimum number of bytes that are needed to attempt to sniff an mp4 file.
1.25 +static const unsigned MP4_MIN_BYTES_COUNT = 12;
1.26 +// The maximum number of bytes to consider when attempting to sniff a file.
1.27 +static const uint32_t MAX_BYTES_SNIFFED = 512;
1.28 +// The maximum number of bytes to consider when attempting to sniff for a mp3
1.29 +// bitstream.
1.30 +// This is 320kbps * 144 / 32kHz + 1 padding byte + 4 bytes of capture pattern.
1.31 +static const uint32_t MAX_BYTES_SNIFFED_MP3 = 320 * 144 / 32 + 1 + 4;
1.32 +
1.33 +NS_IMPL_ISUPPORTS(nsMediaSniffer, nsIContentSniffer)
1.34 +
1.35 +nsMediaSniffer::nsMediaSnifferEntry nsMediaSniffer::sSnifferEntries[] = {
1.36 + // The string OggS, followed by the null byte.
1.37 + PATTERN_ENTRY("\xFF\xFF\xFF\xFF\xFF", "OggS", APPLICATION_OGG),
1.38 + // The string RIFF, followed by four bytes, followed by the string WAVE
1.39 + PATTERN_ENTRY("\xFF\xFF\xFF\xFF\x00\x00\x00\x00\xFF\xFF\xFF\xFF", "RIFF\x00\x00\x00\x00WAVE", AUDIO_WAV),
1.40 + // mp3 with ID3 tags, the string "ID3".
1.41 + PATTERN_ENTRY("\xFF\xFF\xFF", "ID3", AUDIO_MP3)
1.42 +};
1.43 +
1.44 +// This function implements mp4 sniffing algorithm, described at
1.45 +// http://mimesniff.spec.whatwg.org/#signature-for-mp4
1.46 +static bool MatchesMP4(const uint8_t* aData, const uint32_t aLength)
1.47 +{
1.48 + if (aLength <= MP4_MIN_BYTES_COUNT) {
1.49 + return false;
1.50 + }
1.51 + // Conversion from big endian to host byte order.
1.52 + uint32_t boxSize = (uint32_t)(aData[3] | aData[2] << 8 | aData[1] << 16 | aData[0] << 24);
1.53 +
1.54 + // Boxsize should be evenly divisible by 4.
1.55 + if (boxSize % 4 || aLength < boxSize) {
1.56 + return false;
1.57 + }
1.58 + // The string "ftyp".
1.59 + if (aData[4] != 0x66 ||
1.60 + aData[5] != 0x74 ||
1.61 + aData[6] != 0x79 ||
1.62 + aData[7] != 0x70) {
1.63 + return false;
1.64 + }
1.65 + for (uint32_t i = 2; i <= boxSize / 4 - 1 ; i++) {
1.66 + if (i == 3) {
1.67 + continue;
1.68 + }
1.69 + // The string "mp42" or "mp41".
1.70 + if (aData[4*i] == 0x6D &&
1.71 + aData[4*i+1] == 0x70 &&
1.72 + aData[4*i+2] == 0x34) {
1.73 + return true;
1.74 + }
1.75 + // The string "isom" or "iso2".
1.76 + if (aData[4*i] == 0x69 &&
1.77 + aData[4*i+1] == 0x73 &&
1.78 + aData[4*i+2] == 0x6F &&
1.79 + (aData[4*i+3] == 0x6D || aData[4*i+3] == 0x32)) {
1.80 + return true;
1.81 + }
1.82 + }
1.83 + return false;
1.84 +}
1.85 +
1.86 +static bool MatchesWebM(const uint8_t* aData, const uint32_t aLength)
1.87 +{
1.88 +#ifdef MOZ_WEBM
1.89 + return nestegg_sniff((uint8_t*)aData, aLength) ? true : false;
1.90 +#else
1.91 + return false;
1.92 +#endif
1.93 +}
1.94 +
1.95 +// This function implements mp3 sniffing based on parsing
1.96 +// packet headers and looking for expected boundaries.
1.97 +static bool MatchesMP3(const uint8_t* aData, const uint32_t aLength)
1.98 +{
1.99 + return mp3_sniff(aData, (long)aLength);
1.100 +}
1.101 +
1.102 +NS_IMETHODIMP
1.103 +nsMediaSniffer::GetMIMETypeFromContent(nsIRequest* aRequest,
1.104 + const uint8_t* aData,
1.105 + const uint32_t aLength,
1.106 + nsACString& aSniffedType)
1.107 +{
1.108 + // For media, we want to sniff only if the Content-Type is unknown, or if it
1.109 + // is application/octet-stream.
1.110 + nsCOMPtr<nsIChannel> channel = do_QueryInterface(aRequest);
1.111 + if (channel) {
1.112 + nsAutoCString contentType;
1.113 + nsresult rv = channel->GetContentType(contentType);
1.114 + NS_ENSURE_SUCCESS(rv, rv);
1.115 + if (!contentType.IsEmpty() &&
1.116 + !contentType.EqualsLiteral(APPLICATION_OCTET_STREAM) &&
1.117 + !contentType.EqualsLiteral(UNKNOWN_CONTENT_TYPE)) {
1.118 + return NS_ERROR_NOT_AVAILABLE;
1.119 + }
1.120 + }
1.121 +
1.122 + const uint32_t clampedLength = std::min(aLength, MAX_BYTES_SNIFFED);
1.123 +
1.124 + for (uint32_t i = 0; i < mozilla::ArrayLength(sSnifferEntries); ++i) {
1.125 + const nsMediaSnifferEntry& currentEntry = sSnifferEntries[i];
1.126 + if (clampedLength < currentEntry.mLength || currentEntry.mLength == 0) {
1.127 + continue;
1.128 + }
1.129 + bool matched = true;
1.130 + for (uint32_t j = 0; j < currentEntry.mLength; ++j) {
1.131 + if ((currentEntry.mMask[j] & aData[j]) != currentEntry.mPattern[j]) {
1.132 + matched = false;
1.133 + break;
1.134 + }
1.135 + }
1.136 + if (matched) {
1.137 + aSniffedType.AssignASCII(currentEntry.mContentType);
1.138 + return NS_OK;
1.139 + }
1.140 + }
1.141 +
1.142 + if (MatchesMP4(aData, clampedLength)) {
1.143 + aSniffedType.AssignLiteral(VIDEO_MP4);
1.144 + return NS_OK;
1.145 + }
1.146 +
1.147 + if (MatchesWebM(aData, clampedLength)) {
1.148 + aSniffedType.AssignLiteral(VIDEO_WEBM);
1.149 + return NS_OK;
1.150 + }
1.151 +
1.152 + // Bug 950023: 512 bytes are often not enough to sniff for mp3.
1.153 + if (MatchesMP3(aData, std::min(aLength, MAX_BYTES_SNIFFED_MP3))) {
1.154 + aSniffedType.AssignLiteral(AUDIO_MP3);
1.155 + return NS_OK;
1.156 + }
1.157 +
1.158 + // Could not sniff the media type, we are required to set it to
1.159 + // application/octet-stream.
1.160 + aSniffedType.AssignLiteral(APPLICATION_OCTET_STREAM);
1.161 + return NS_ERROR_NOT_AVAILABLE;
1.162 +}
