Fix erroneous "format unsupported " error in Play Movies

Only the first 64K of the movie is pulled when sniffing,
if the widevine version metadata is not present in the
sniff buffer then a "format unsupported" error would occur.

This change increases the sniff buffer size to 128K.

bug: 9351294
Change-Id: If162cbea6915bf2b70122afd30e556e9206e8e43

proprietary/wvm/WVMExtractorImpl.cpp

@@ -72,22 +72,26 @@ WVMLoadableExtractor *GetInstance(sp<DataSource> dataSource) {
 }
 
 bool IsWidevineMedia(const sp<DataSource>& dataSource) {
-    char buffer[64 * 1024];
-
     String8 uri = dataSource->getUri();
     if (uri.getPathExtension() == ".m3u8" || uri.find(".m3u8?") != -1) {
         // can't sniff live streams - check for .m3u8 file extension
         return true;
     }
 
-    ssize_t bytesRead = dataSource->readAt(0, buffer, sizeof(buffer));
-    if (bytesRead < (ssize_t)sizeof(buffer)) {
-        ALOGV("IsWidevineMedia - insufficient data: %d", (int)bytesRead);
-        return false;
-    }
+    ssize_t kSniffSize = 128 * 1024;
+    char *buffer = new char[kSniffSize];
+    bool result = false;
 
-    setenv("WV_SILENT", "true", 1);
-    bool result = WV_IsWidevineMedia(buffer, sizeof(buffer));
+    if (buffer) {
+        ssize_t bytesRead = dataSource->readAt(0, buffer, kSniffSize);
+        if (bytesRead < kSniffSize) {
+            ALOGV("IsWidevineMedia - insufficient data: %d", (int)bytesRead);
+        } else {
+            setenv("WV_SILENT", "true", 1);
+            result = WV_IsWidevineMedia(buffer, kSniffSize);
+        }
+        delete[] buffer;
+    }
     return result;
 }