Allocate extra buffer space in FrameObject in case of H264.

webrtc/modules/video_coding/frame_object.cc

Index: webrtc/modules/video_coding/frame_object.cc
diff --git a/webrtc/modules/video_coding/frame_object.cc b/webrtc/modules/video_coding/frame_object.cc
index acfb25d28d3594e4a0d2047091f20c2238ff8a3a..88205277af1c5fa7c0e2a3ec9e06788a96aff263 100644
--- a/webrtc/modules/video_coding/frame_object.cc
+++ b/webrtc/modules/video_coding/frame_object.cc
@@ -35,6 +35,10 @@ RtpFrameObject::RtpFrameObject(PacketBuffer* packet_buffer,
       times_nacked_(times_nacked) {
   VCMPacket* packet = packet_buffer_->GetPacket(first_seq_num);
   if (packet) {
+    // RtpFrameObject members
+    frame_type_ = packet->frameType;
+    codec_type_ = packet->codec;
+
     // TODO(philipel): Remove when encoded image is replaced by FrameObject.
     // VCMEncodedFrame members
     CopyCodecSpecific(&packet->video_header);
@@ -42,16 +46,23 @@ RtpFrameObject::RtpFrameObject(PacketBuffer* packet_buffer,
     _payloadType = packet->payloadType;
     _timeStamp = packet->timestamp;
     ntp_time_ms_ = packet->ntp_time_ms_;
-    _buffer = new uint8_t[frame_size]();
-    _size = frame_size;
+
+    // Since FFmpeg use an optimized bitstream reader that reads in chunks of
+    // 32/64 bits we have to add at least that much padding to the buffer
+    // to make sure the decoder doesn't read out of bounds.
+    // NOTE! EncodedImage::_size is the size of the buffer (think capacity of
+    //       an std::vector) and EncodedImage::_length is the actual size of
+    //       the bitstream (think size of an std::vector).
+    if (codec_type_ == kVideoCodecH264)
+      _size = frame_size + EncodedImage::kBufferPaddingBytesH264;
+    else
+      _size = frame_size;
+
+    _buffer = new uint8_t[_size];
     _length = frame_size;
     _frameType = packet->frameType;
     GetBitstream(_buffer);
 
-    // RtpFrameObject members
-    frame_type_ = packet->frameType;
-    codec_type_ = packet->codec;
-
     // FrameObject members
     timestamp = packet->timestamp;
   }