Support multiple media tracks in MSE / ChunkDemuxer

third_party/WebKit/LayoutTests/http/tests/media/media-source/mediasource-addsourcebuffer.html

Index: third_party/WebKit/LayoutTests/http/tests/media/media-source/mediasource-addsourcebuffer.html
diff --git a/third_party/WebKit/LayoutTests/http/tests/media/media-source/mediasource-addsourcebuffer.html b/third_party/WebKit/LayoutTests/http/tests/media/media-source/mediasource-addsourcebuffer.html
index 2fe975473577e630e711e79848d6ac0d7b5f6045..d9d0eb23639f9a3fc3019d6bbd4f11de5fadbdc9 100644
--- a/third_party/WebKit/LayoutTests/http/tests/media/media-source/mediasource-addsourcebuffer.html
+++ b/third_party/WebKit/LayoutTests/http/tests/media/media-source/mediasource-addsourcebuffer.html
@@ -134,24 +134,18 @@
               test.done();
           }, "Test addSourceBuffer() with AAC and H.264 in separate SourceBuffers");
 
-          mediasource_test(function(test, mediaElement, mediaSource)
+          mediasource_testafterdataloaded(function(test, mediaElement, mediaSource, segmentInfo, sourceBuffer, mediaData)
           {
-              var reachedLimit = false;
-
-             // The 20 here is an arbitrary upper limit to make sure the test terminates. This test
-             // assumes that implementations won't support more than 20 SourceBuffers simultaneously.
-             for (var i = 0; i < 20; ++i) {
-                 try {
-                     mediaSource.addSourceBuffer(MediaSourceUtil.AUDIO_VIDEO_TYPE);
-                 } catch(e) {
-                     assert_equals(e.name, "QuotaExceededError");
-                     reachedLimit = true;
-                     break;
-                 }
-             }
-             assert_true(reachedLimit, "Reached SourceBuffer limit.");
-             test.done();
-          }, "Test addSourceBuffer() QuotaExceededError.");
+              sourceBuffer.appendBuffer(mediaData);
+              test.expectEvent(sourceBuffer, "updateend");
+              test.waitForExpectedEvents(function()
+              {
+                  assert_throws({name: "QuotaExceededError"},
+                      function() { mediaSource.addSourceBuffer(MediaSourceUtil.AUDIO_VIDEO_TYPE); },
+                      "addSourceBuffer must throw an exception if the MediaSource has already got some data");
+                  test.done();
+              });
+          }, "Test addSourceBuffer() throws QuotaExceededError after data has been appended.");

[wolenetz, 2016/09/13 21:03:14]

nit: change this to be similar to the unit test: only fail after the last byte
of the first init segment (for all SourceBuffers currently in
mediaSource.sourceBuffers) is appended. Or add secondary tests here that do
deeper coverage of this Chrome-specific behavior.

[servolk, 2016/09/14 18:15:27]

Wait. First, there's only one sourceBuffer here, the second one is never added
due to data already being appended to the first one and thus ChunkDemuxer being
in the INITIALIZED state.
Second, I'm not sure how we can detect the "last byte of the init segment" here.
Do we need to parse mediaData somehow?

[wolenetz, 2016/09/14 23:31:21]

I'm being a little pedantic here, but tests kind of are :)

segmentInfo describes mediaData, so something like the following can extract
just the init segment:
// var initSegment = mediaData.subarray(segmentInfo.init.offset,
segmentInfo.init.offset + segmentInfo.init.size);

Then, append all but the last N bytes of initSegment to the only sourceBuffer
currently added. At this point:
a) adding a second sourcebuffer should succeed
b) then removing that second sourcebuffer should succeed.
c) then append the last N bytes of the init segment to the first sourcebuffer
d) then adding another sourcebuffer should fail.

Given this sequence of operations is a bit complex versus this patch set's test,
I suggest adding a secondary test that drills down into a->d.

Note that ideally N == 1, but there could be mistakes in the segmentInfo or the
muxed media might contain optional pieces within that init segment range. I'd
try N==1 for both webm and mp4 first, and if that works, just keep to 1.

[wolenetz, 2016/09/14 23:34:28]

mediasource-util.js includes a helper for this. Use it like so:
var initSegment = extractSegmentData(mediaData, segmentInfo.init);

[servolk, 2016/09/15 00:18:32]

Ah, ok, I see what you mean now. Done.
I guess we could append just half of the init segment if we wanted to avoid any
potential issues with init segment not being defined precisely in the
segmentInfo, but at least for now even N-1 seems to be working, so I kept it.

         </script>
     </body>
 </html>