Changeset 287899 in webkit

Timestamp:

Jan 11, 2022, 3:25:09 PM (4 years ago)

Author:

Peng Liu

Message:

DataURLResourceMediaLoader decodes the URL repeatedly during a video playback
​https://bugs.webkit.org/show_bug.cgi?id=234940

Reviewed by Darin Adler.

In r264864, we adopted a new SPI to tell AVFoundation that the entire file is available for custom URLs.
As a result, during a video playback, AVFoundation will request small data ranges instead of "caching"
the whole file again.

However, that leads to efficiency issue for DataURLResourceMediaLoader. Because it needs to decode the whole
URL when AVFoundation requests a data range, which is inefficient when the URL is very long.

This patch reverts the change in r264864 for the DataURLResourceMediaLoader case to fix the performance issue.
If DataURLDecoder::decode() supports decoding a data range in the future, we can change it back for better
memory efficiency.

• platform/graphics/avfoundation/objc/WebCoreAVFResourceLoader.mm:

(WebCore::WebCoreAVFResourceLoader::responseReceived):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/graphics/avfoundation/objc/WebCoreAVFResourceLoader.mm (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2022-01-11  Peng Liu  <peng.liu6@apple.com>
+
+        DataURLResourceMediaLoader decodes the URL repeatedly during a video playback
+        https://bugs.webkit.org/show_bug.cgi?id=234940
+
+        Reviewed by Darin Adler.
+
+        In r264864, we adopted a new SPI to tell AVFoundation that the entire file is available for custom URLs.
+        As a result, during a video playback, AVFoundation will request small data ranges instead of "caching"
+        the whole file again.
+
+        However, that leads to efficiency issue for DataURLResourceMediaLoader. Because it needs to decode the whole
+        URL when AVFoundation requests a data range, which is inefficient when the URL is very long.
+
+        This patch reverts the change in r264864 for the DataURLResourceMediaLoader case to fix the performance issue.
+        If DataURLDecoder::decode() supports decoding a data range in the future, we can change it back for better
+        memory efficiency.
+
+        * platform/graphics/avfoundation/objc/WebCoreAVFResourceLoader.mm:
+        (WebCore::WebCoreAVFResourceLoader::responseReceived):
+
 2022-01-11  Antoine Quint  <graouts@webkit.org>
 

trunk/Source/WebCore/platform/graphics/avfoundation/objc/WebCoreAVFResourceLoader.mm

@@ -358 +358 @@
         [contentInfo setContentLength:contentRange.isValid() ? contentRange.instanceLength() : response.expectedContentLength()];
         [contentInfo setByteRangeAccessSupported:YES];
-        
-        if ([contentInfo respondsToSelector:@selector(setEntireLengthAvailableOnDemand:)])
+
+        // Do not set "EntireLengthAvailableOnDemand" to YES when the loader is DataURLResourceMediaLoader.
+        // When the property is YES, AVAssetResourceLoader will request small data ranges over and over again
+        // during the playback. For DataURLResourceMediaLoader, that means it needs to decode the URL repeatedly,
+        // which is very inefficient for long URLs.
+        if (!m_dataURLMediaLoader && [contentInfo respondsToSelector:@selector(setEntireLengthAvailableOnDemand:)])
             [contentInfo setEntireLengthAvailableOnDemand:YES];