[tbb-commits] [tor-browser/tor-browser-45.4.0esr-6.5-1] Bug 1291543 - [1.1] Accept partial information from VBR headers. r=jya

[gk at torproject.org]

commit 6715852d4487a4b3176c70f34358f5894954bbe2
Author: Eugen Sawin <esawin at mozilla.com>
Date:   Wed Aug 3 15:34:30 2016 +0200

    Bug 1291543 - [1.1] Accept partial information from VBR headers. r=jya
    
    This fixes our bug 20160.
---
 dom/media/MP3Demuxer.cpp | 16 ++++++++++------
 dom/media/MP3Demuxer.h   |  5 ++++-
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/dom/media/MP3Demuxer.cpp b/dom/media/MP3Demuxer.cpp
index 88a20dcb..773f996 100644
--- a/dom/media/MP3Demuxer.cpp
+++ b/dom/media/MP3Demuxer.cpp
@@ -347,7 +347,7 @@ MP3TrackDemuxer::Duration() const {
 
   int64_t numFrames = 0;
   const auto numAudioFrames = mParser.VBRInfo().NumAudioFrames();
-  if (mParser.VBRInfo().IsValid()) {
+  if (mParser.VBRInfo().IsValid() && numAudioFrames.valueOr(0) + 1 > 1) {
     // VBR headers don't include the VBR header frame.
     numFrames = numAudioFrames.value() + 1;
   } else {
@@ -513,7 +513,6 @@ MP3TrackDemuxer::GetNextFrame(const MediaByteRange& aRange) {
 
   if (mNumParsedFrames == 1) {
     // First frame parsed, let's read VBR info if available.
-    // TODO: read info that helps with seeking (bug 1163667).
     ByteReader reader(frame->Data(), frame->Size());
     mParser.ParseVBRHeader(&reader);
     reader.DiscardRemaining();
@@ -534,7 +533,7 @@ MP3TrackDemuxer::OffsetFromFrameIndex(int64_t aFrameIndex) const {
   int64_t offset = 0;
   const auto& vbr = mParser.VBRInfo();
 
-  if (vbr.IsValid()) {
+  if (vbr.IsComplete()) {
     offset = mFirstFrameOffset + aFrameIndex * vbr.NumBytes().value() /
              vbr.NumAudioFrames().value();
   } else if (AverageFrameLength() > 0) {
@@ -550,7 +549,7 @@ MP3TrackDemuxer::FrameIndexFromOffset(int64_t aOffset) const {
   int64_t frameIndex = 0;
   const auto& vbr = mParser.VBRInfo();
 
-  if (vbr.IsValid()) {
+  if (vbr.IsComplete()) {
     frameIndex = static_cast<float>(aOffset - mFirstFrameOffset) /
                  vbr.NumBytes().value() * vbr.NumAudioFrames().value();
     frameIndex = std::min<int64_t>(vbr.NumAudioFrames().value(), frameIndex);
@@ -626,7 +625,7 @@ MP3TrackDemuxer::AverageFrameLength() const {
     return static_cast<double>(mTotalFrameLen) / mNumParsedFrames;
   }
   const auto& vbr = mParser.VBRInfo();
-  if (vbr.IsValid() && vbr.NumAudioFrames().value() + 1) {
+  if (vbr.IsComplete() && vbr.NumAudioFrames().value() + 1) {
     return static_cast<double>(vbr.NumBytes().value()) /
            (vbr.NumAudioFrames().value() + 1);
   }
@@ -964,7 +963,12 @@ FrameParser::VBRHeader::IsTOCPresent() const {
 
 bool
 FrameParser::VBRHeader::IsValid() const {
-  return mType != NONE &&
+  return mType != NONE;
+}
+
+bool
+FrameParser::VBRHeader::IsComplete() const {
+  return IsValid() &&
          mNumAudioFrames.valueOr(0) > 0 &&
          mNumBytes.valueOr(0) > 0 &&
          // We don't care about the scale for any computations here.
diff --git a/dom/media/MP3Demuxer.h b/dom/media/MP3Demuxer.h
index d98cb73..54e380a 100644
--- a/dom/media/MP3Demuxer.h
+++ b/dom/media/MP3Demuxer.h
@@ -232,9 +232,12 @@ public:
     // Returns true iff Xing/Info TOC (table of contents) is present.
     bool IsTOCPresent() const;
 
-    // Returns whether the header is valid (containing reasonable field values).
+    // Returns whether the header is valid (type XING or VBRI).
     bool IsValid() const;
 
+    // Returns whether the header is valid and contains reasonable non-zero field values.
+    bool IsComplete() const;
+
     // Returns the byte offset for the given duration percentage as a factor
     // (0: begin, 1.0: end).
     int64_t Offset(float aDurationFac) const;