Fix SIGABRT when playing mp4 file

If the track duration was shorter than the segment duration, the calculated
encoder padding would be negative, resulting in a crash.
b/11823061
https://code.google.com/p/android/issues/detail?id=62610

Change-Id: I3989ad88caea38d212b61355c15aec13382c6116

1 files changed, 6 insertions, 0 deletions

diff --git a/media/libstagefright/MPEG4Extractor.cpp b/media/libstagefright/MPEG4Extractor.cpp
index d0b6185..13e22d6 100644
--- a/media/libstagefright/MPEG4Extractor.cpp
+++ b/media/libstagefright/MPEG4Extractor.cpp
@@ -963,6 +963,12 @@ status_t MPEG4Extractor::parseChunk(off64_t *offset, int depth) {
                     mLastTrack->meta->setInt32(kKeyEncoderDelay, delay);
 
                     int64_t paddingus = duration - (segment_duration + media_time);
+                    if (paddingus < 0) {
+                        // track duration from media header (which is what kKeyDuration is) might
+                        // be slightly shorter than the segment duration, which would make the
+                        // padding negative. Clamp to zero.
+                        paddingus = 0;
+                    }
                     int64_t paddingsamples = (paddingus * samplerate + 500000) / 1000000;
                     mLastTrack->meta->setInt32(kKeyEncoderPadding, paddingsamples);
                 }