Source code

Revision control

Other Tools

/* -*- 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 "ADTSDemuxer.h"
#include "FlacDemuxer.h"
#include "mozilla/ArrayUtils.h"
#include "mozilla/ModuleUtils.h"
#include "mozilla/ScopeExit.h"
#include "mp3sniff.h"
#include "nestegg/nestegg.h"
#include "nsHttpChannel.h"
#include "nsIClassInfoImpl.h"
#include "nsIChannel.h"
#include "nsMediaSniffer.h"
#include "nsMimeTypes.h"
#include "nsQueryObject.h"
#include "nsString.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),
PATTERN_ENTRY("\xFF\xFF\xFF\xFF\xFF\xFF\xFF", "#EXTM3U",
APPLICATION_MPEGURL)};
// 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\xFF", "3gp4",
VIDEO_MP4), // 3gp4 is based on MP4
PATTERN_ENTRY("\xFF\xFF\xFF", "3gp",
VIDEO_3GPP), // Could be 3gp5, ...
PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "M4V ", VIDEO_MP4),
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),
PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "avif", IMAGE_AVIF),
};
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
// audio), and 3GPP.
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);
}
static bool MatchesADTS(const uint8_t* aData, const uint32_t aLength) {
return mozilla::ADTSDemuxer::ADTSSniffer(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) {
nsCOMPtr<nsILoadInfo> loadInfo = channel->LoadInfo();
if (loadInfo->GetSkipContentSniffing()) {
return NS_ERROR_NOT_AVAILABLE;
}
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);
auto maybeUpdate = mozilla::MakeScopeExit([&channel]() {
if (channel && XRE_IsParentProcess()) {
if (RefPtr<mozilla::net::nsHttpChannel> httpChannel =
do_QueryObject(channel)) {
// If the audio or video type pattern matching algorithm given bytes
// does not return undefined, then disable the further check and allow
// the response.
httpChannel->DisableIsOpaqueResponseAllowedAfterSniffCheck(
mozilla::net::nsHttpChannel::SnifferType::Media);
}
};
});
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;
}
if (MatchesADTS(aData, clampedLength)) {
aSniffedType.AssignLiteral(AUDIO_AAC);
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;
}
maybeUpdate.release();
// 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;
}