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icbakericbaker
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Experiment with adding a third SeekHead
This file was crafted by hand in a hex editor by modifying `sample.mkv`: 1. Adding two SeekHead elements at the end, each with a single Seek entry, with the first pointing at the Cues element and the second pointing at the Tags element. 2. Update the original SeekHead element so the Seek entries that previously pointed to the Cues and Tags element now point out the two new SeekHead elements we added. The resulting file is successfully parsed by `mkvinfo` and playable with VLC. The dump files were generated with all changes in MatroskaExtractor reverted (which is why they're unseekable). Bringing the MatroskaExtractor changes back and running the test results in a larger than expected diff in the dump file. Specifically all the samples are dropped.
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7 files changed

+1082
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lines changed

7 files changed

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‎libraries/extractor/src/test/java/androidx/media3/extractor/mkv/MatroskaExtractorTest.java

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Original file line numberDiff line numberDiff line change
@@ -151,6 +151,16 @@ public void mkvSample_withRecursiveSeekHead() throws Exception {
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simulationConfig);
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}
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@Test
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public void mkvSample_threeSeekHeads() throws Exception {
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ExtractorAsserts.assertBehavior(
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getExtractorFactory(subtitlesParsedDuringExtraction),
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"media/mkv/sample_three_seekheads.mkv",
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getAssertionConfigWithPrefix(
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"media/mkv/sample_three_seekheads.mkv", subtitlesParsedDuringExtraction),
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simulationConfig);
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}
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@Test
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public void mkvSample_withVorbisAudio() throws Exception {
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ExtractorAsserts.assertBehavior(

‎libraries/test_data/src/test/assets/extractordumps/mkv/sample_three_seekheads.mkv.0.dump

Lines changed: 268 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,268 @@
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seekMap:
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isSeekable = false
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duration = 1072000
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getPosition(0) = [[timeUs=0, position=0]]
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numberOfTracks = 2
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track 1:
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total output bytes = 89502
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sample count = 30
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format 0:
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id = 1
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containerMimeType = video/x-matroska
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sampleMimeType = video/avc
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codecs = avc1.640034
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width = 1080
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height = 720
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selectionFlags = [default]
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language = und
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initializationData:
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data = length 30, hash F6F3D010
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data = length 10, hash 7A0D0F2B
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sample 0:
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time = 67000
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flags = 1
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data = length 36477, hash F0F36CFE
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sample 1:
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time = 134000
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flags = 0
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data = length 5341, hash 40B85E2
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sample 2:
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time = 100000
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flags = 0
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data = length 596, hash 357B4D92
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sample 3:
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time = 267000
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flags = 0
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data = length 7704, hash A39EDA06
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sample 4:
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time = 200000
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flags = 0
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data = length 989, hash 2813C72D
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sample 5:
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time = 167000
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flags = 0
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data = length 721, hash C50D1C73
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sample 6:
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time = 234000
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flags = 0
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data = length 519, hash 65FE1911
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sample 7:
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time = 400000
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flags = 0
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data = length 6160, hash E1CAC0EC
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sample 8:
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time = 334000
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flags = 0
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data = length 953, hash 7160C661
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sample 9:
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time = 300000
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flags = 0
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data = length 620, hash 7A7AE07C
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sample 10:
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time = 367000
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flags = 0
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data = length 405, hash 5CC7F4E7
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sample 11:
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time = 500000
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flags = 0
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data = length 4852, hash 9DB6979D
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sample 12:
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time = 467000
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flags = 0
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data = length 547, hash E31A6979
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sample 13:
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time = 434000
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flags = 0
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data = length 570, hash FEC40D00
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sample 14:
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time = 634000
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flags = 0
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data = length 5525, hash 7C478F7E
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sample 15:
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time = 567000
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flags = 0
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data = length 1082, hash DA07059A
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sample 16:
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time = 534000
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flags = 0
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data = length 807, hash 93478E6B
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sample 17:
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time = 600000
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flags = 0
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data = length 744, hash 9A8E6026
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sample 18:
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time = 767000
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flags = 0
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data = length 4732, hash C73B23C0
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sample 19:
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time = 700000
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flags = 0
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data = length 1004, hash 8A19A228
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sample 20:
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time = 667000
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flags = 0
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data = length 794, hash 8126022C
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sample 21:
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time = 734000
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flags = 0
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data = length 645, hash F08300E5
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sample 22:
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time = 900000
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flags = 0
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data = length 2684, hash 727FE378
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sample 23:
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time = 834000
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flags = 0
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data = length 787, hash 419A7821
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sample 24:
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time = 800000
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flags = 0
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data = length 649, hash 5C159346
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sample 25:
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time = 867000
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flags = 0
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data = length 509, hash F912D655
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sample 26:
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time = 1034000
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flags = 0
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data = length 1226, hash 29815C21
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sample 27:
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time = 967000
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flags = 0
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data = length 898, hash D997AD0A
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sample 28:
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time = 934000
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flags = 0
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data = length 476, hash A0423645
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sample 29:
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time = 1000000
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flags = 0
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data = length 486, hash DDF32CBB
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track 2:
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total output bytes = 12120
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sample count = 29
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format 0:
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id = 2
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containerMimeType = video/x-matroska
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sampleMimeType = audio/ac3
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channelCount = 1
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sampleRate = 44100
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selectionFlags = [default]
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language = und
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sample 0:
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time = 129000
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flags = 1
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data = length 416, hash 211F2286
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sample 1:
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time = 164000
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flags = 1
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data = length 418, hash 77425A86
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sample 2:
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time = 198829
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flags = 1
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data = length 418, hash A0FE5CA1
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sample 3:
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time = 233000
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flags = 1
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data = length 418, hash 2309B066
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sample 4:
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time = 268000
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flags = 1
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data = length 418, hash 928A653B
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sample 5:
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time = 303000
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flags = 1
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data = length 418, hash 3422F0CB
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sample 6:
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time = 337829
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flags = 1
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data = length 418, hash EFF43D5B
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sample 7:
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time = 373000
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flags = 1
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data = length 418, hash FC8093C7
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sample 8:
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time = 408000
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flags = 1
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data = length 418, hash CCC08A16
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sample 9:
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time = 443000
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flags = 1
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data = length 418, hash 2A6EE863
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sample 10:
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time = 477829
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flags = 1
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data = length 418, hash D69A9251
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sample 11:
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time = 512000
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flags = 1
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data = length 418, hash BCFB758D
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sample 12:
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time = 547000
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flags = 1
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data = length 418, hash 11B66799
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sample 13:
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time = 581829
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flags = 1
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data = length 418, hash C824D392
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sample 14:
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time = 617000
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flags = 1
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data = length 418, hash C167D872
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sample 15:
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time = 652000
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flags = 1
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data = length 418, hash 4221C855
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sample 16:
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time = 687000
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flags = 1
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data = length 418, hash 4D4FF934
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sample 17:
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time = 721829
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flags = 1
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data = length 418, hash 984AA025
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sample 18:
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time = 757000
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flags = 1
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data = length 418, hash BB788B46
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sample 19:
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time = 791000
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flags = 1
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data = length 418, hash 9EFBFD97
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sample 20:
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time = 826000
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flags = 1
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data = length 418, hash DF1A460C
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sample 21:
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time = 860829
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flags = 1
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data = length 418, hash 2BDB56A
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sample 22:
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time = 896000
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flags = 1
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data = length 418, hash CA230060
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sample 23:
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time = 931000
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flags = 1
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data = length 418, hash D2F19F41
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sample 24:
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time = 965000
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flags = 1
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data = length 418, hash AF392D79
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sample 25:
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time = 999829
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flags = 1
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data = length 418, hash C5D7F2A3
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sample 26:
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time = 1035000
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flags = 1
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data = length 418, hash 733A35AE
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sample 27:
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time = 1069829
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flags = 1
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data = length 418, hash DE46E5D3
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sample 28:
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time = 1104000
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flags = 1
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data = length 418, hash 56AB8D37
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tracksEnded = true

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