--- a/content/media/nsMediaCache.cpp
+++ b/content/media/nsMediaCache.cpp
@@ -636,17 +636,17 @@ nsMediaCache::WriteCacheFile(PRInt64 aOf
   return NS_OK;
 }
 
 static PRInt32 GetMaxBlocks()
 {
   // We look up the cache size every time. This means dynamic changes
   // to the pref are applied.
   // Cache size is in KB
-  PRInt32 cacheSize = nsContentUtils::GetIntPref("media.cache_size", 50*1024);
+  PRInt32 cacheSize = nsContentUtils::GetIntPref("media.cache_size", 500*1024);
   PRInt64 maxBlocks = PRInt64(cacheSize)*1024/nsMediaCache::BLOCK_SIZE;
   maxBlocks = PR_MAX(maxBlocks, 1);
   return PRInt32(PR_MIN(maxBlocks, PR_INT32_MAX));
 }
 
 PRInt32
 nsMediaCache::FindBlockForIncomingData(TimeStamp aNow,
                                        nsMediaCacheStream* aStream)

--- a/content/media/nsMediaCache.h
+++ b/content/media/nsMediaCache.h
@@ -91,17 +91,17 @@
  * is marked "delete on close" so it will automatically disappear in the
  * event of a browser crash or shutdown.
  * 
  * The media cache is block-based. Streams are divided into blocks of a
  * fixed size (currently 4K) and we cache blocks. A single cache contains
  * blocks for all streams.
  * 
  * The cache size is controlled by the media.cache_size preference
- * (which is in KB). The default size is 50MB.
+ * (which is in KB). The default size is 500MB.
  * 
  * The replacement policy predicts a "time of next use" for each block
  * in the cache. When we need to free a block, the block with the latest
  * "time of next use" will be evicted. Blocks are divided into
  * different classes, each class having its own predictor:
  * FREE_BLOCK: these blocks are effectively infinitely far in the future;
  * a free block will always be chosen for replacement before other classes
  * of blocks.

--- a/modules/libpref/src/init/all.js
+++ b/modules/libpref/src/init/all.js
@@ -149,17 +149,17 @@ pref("browser.chrome.image_icons.max_siz
 
 pref("browser.triple_click_selects_paragraph", true);
 
 // When loading <video> or <audio>, check for Access-Control-Allow-Origin
 // header, and disallow the connection if not present or permitted.
 pref("media.enforce_same_site_origin", false);
 
 // Media cache size in kilobytes
-pref("media.cache_size", 51200);
+pref("media.cache_size", 512000);
 
 #ifdef MOZ_OGG
 pref("media.ogg.enabled", true);
 #endif
 #ifdef MOZ_WAVE
 pref("media.wave.enabled", true);
 #endif
 #ifdef MOZ_WEBM