From 7567469034fd9032cc32b3b8366467704ac4a06b Mon Sep 17 00:00:00 2001
From: Anthony Jones <ajones@mozilla.com>
Date: Tue, 16 Dec 2014 18:10:44 +1300
Subject: [PATCH] Bug 1098126 - Remove duplication in MP4 demuxer seek;
 r=mattwoodrow

---
 .../media/libstagefright/MPEG4Extractor.cpp   | 102 ++++++++----------
 1 file changed, 42 insertions(+), 60 deletions(-)

diff --git a/media/libstagefright/frameworks/av/media/libstagefright/MPEG4Extractor.cpp b/media/libstagefright/frameworks/av/media/libstagefright/MPEG4Extractor.cpp
index 7adcb6f6e22..4b22bf3db71 100644
--- a/media/libstagefright/frameworks/av/media/libstagefright/MPEG4Extractor.cpp
+++ b/media/libstagefright/frameworks/av/media/libstagefright/MPEG4Extractor.cpp
@@ -112,6 +112,7 @@ private:
     status_t parseSampleAuxiliaryInformationSizes(off64_t offset, off64_t size);
     status_t parseSampleAuxiliaryInformationOffsets(off64_t offset, off64_t size);
     void lookForMoof();
+    status_t moveToNextFragment();
 
     struct TrackFragmentHeaderInfo {
         enum Flags {
@@ -3583,6 +3584,34 @@ status_t MPEG4Source::read(
     }
 }
 
+status_t MPEG4Source::moveToNextFragment() {
+    off64_t nextMoof = mNextMoofOffset;
+    mCurrentSamples.clear();
+    mDeferredSaio.clear();
+    mDeferredSaiz.clear();
+    mCurrentSampleIndex = 0;
+    uint32_t hdr[2];
+    do {
+        if (mDataSource->readAt(nextMoof, hdr, 8) < 8) {
+            return ERROR_END_OF_STREAM;
+        }
+        uint64_t chunk_size = ntohl(hdr[0]);
+        uint32_t chunk_type = ntohl(hdr[1]);
+
+        // Skip over anything that isn't a moof
+        if (chunk_type != FOURCC('m', 'o', 'o', 'f')) {
+            nextMoof += chunk_size;
+            continue;
+        }
+        mCurrentMoofOffset = nextMoof;
+        status_t ret = parseChunk(&nextMoof);
+        if (ret != OK) {
+            return ret;
+        }
+    } while (mCurrentSamples.size() == 0);
+    return OK;
+}
+
 status_t MPEG4Source::fragmentedRead(
         MediaBuffer **out, const ReadOptions *options) {
 
@@ -3598,10 +3627,6 @@ status_t MPEG4Source::fragmentedRead(
     ReadOptions::SeekMode mode;
     if (options && options->getSeekTo(&seekTimeUs, &mode)) {
 
-        mCurrentSamples.clear();
-        mDeferredSaio.clear();
-        mDeferredSaiz.clear();
-        mCurrentSampleIndex = 0;
         int numSidxEntries = mSegments.size();
         if (numSidxEntries != 0) {
             int64_t totalTime = 0;
@@ -3624,37 +3649,21 @@ status_t MPEG4Source::fragmentedRead(
                 totalOffset += se->mSize;
             }
             mCurrentMoofOffset = totalOffset;
-            mNextMoofOffset = totalOffset;
+            mCurrentSamples.clear();
+            mDeferredSaio.clear();
+            mDeferredSaiz.clear();
+            mCurrentSampleIndex = 0;
             mCurrentTime = totalTime * mTimescale / 1000000ll;
+            mNextMoofOffset = totalOffset;
         }
         else {
             mNextMoofOffset = mFirstMoofOffset;
             uint32_t seekTime = (int32_t) ((seekTimeUs * mTimescale) / 1000000ll);
             while (true) {
-
-                uint32_t hdr[2];
-                do {
-                    off64_t moofOffset = mNextMoofOffset; // lastSample.offset + lastSample.size;
-                    if (mDataSource->readAt(moofOffset, hdr, 8) < 8) {
-                        ALOGV("Seek ERROR_END_OF_STREAM\n");
-                        return ERROR_END_OF_STREAM;
-                    }
-                    uint64_t chunk_size = ntohl(hdr[0]);
-                    uint32_t chunk_type = ntohl(hdr[1]);
-                    char chunk[5];
-                    MakeFourCCString(chunk_type, chunk);
-
-                    // If we're pointing to a segment type or sidx box then we skip them.
-                    if (chunk_type != FOURCC('m', 'o', 'o', 'f')) {
-                        mNextMoofOffset += chunk_size;
-                        continue;
-                    }
-                    mCurrentMoofOffset = moofOffset;
-                    status_t ret = parseChunk(&moofOffset);
-                    if (ret != OK) {
-                        return ret;
-                    }
-                } while (mCurrentSamples.size() == 0);
+                status_t ret = moveToNextFragment();
+                if (ret != OK) {
+                    return ret;
+                }
                 uint32_t time = mCurrentTime;
                 int i;
                 for (i = 0; i < mCurrentSamples.size() && time <= seekTime; i++) {
@@ -3668,11 +3677,6 @@ status_t MPEG4Source::fragmentedRead(
                 if (i != mCurrentSamples.size()) {
                     break;
                 }
-
-                mCurrentSamples.clear();
-                mDeferredSaio.clear();
-                mDeferredSaiz.clear();
-                mCurrentSampleIndex = 0;
             }
             ALOGV("Seeking offset %d; %ldus\n", mCurrentTime - seekTime,
                     (((int64_t) mCurrentTime - seekTime) * 1000000ll) / mTimescale);
@@ -3697,32 +3701,10 @@ status_t MPEG4Source::fragmentedRead(
         newBuffer = true;
 
         if (mCurrentSampleIndex >= mCurrentSamples.size()) {
-            // move to next fragment
-            off64_t nextMoof = mNextMoofOffset; // lastSample.offset + lastSample.size;
-            mCurrentSamples.clear();
-            mDeferredSaio.clear();
-            mDeferredSaiz.clear();
-            mCurrentSampleIndex = 0;
-            uint32_t hdr[2];
-            do {
-                if (mDataSource->readAt(nextMoof, hdr, 8) < 8) {
-                    return ERROR_END_OF_STREAM;
-                }
-                uint64_t chunk_size = ntohl(hdr[0]);
-                uint32_t chunk_type = ntohl(hdr[1]);
-
-                // If we're pointing to a segment type or sidx box then we skip them.
-                if (chunk_type == FOURCC('s', 't', 'y', 'p') ||
-                    chunk_type == FOURCC('s', 'i', 'd', 'x')) {
-                    nextMoof += chunk_size;
-                    continue;
-                }
-                mCurrentMoofOffset = nextMoof;
-                status_t ret = parseChunk(&nextMoof);
-                if (ret != OK) {
-                    return ret;
-                }
-            } while (mCurrentSamples.size() == 0);
+            status_t ret = moveToNextFragment();
+            if (ret != OK) {
+                return ret;
+            }
         }
 
         const Sample *smpl = &mCurrentSamples[mCurrentSampleIndex];