| <!DOCTYPE html> |
| <html> |
| <head> |
| <title>media-source-append-overlapping-equal-decode-key</title> |
| <script src="mp4-generator.js"></script> |
| <script src="../video-test.js"></script> |
| <script> |
| // Regression guard for MSE "Coded Frame Processing" when an incoming sync |
| // sample carries the same (decodeTime, presentationTime) key as a buffered |
| // sample. |
| // |
| // Step 1.14's sync cascade in SourceBufferPrivate::processMediaSample uses |
| // findSampleAfterDecodeKey (std::map::upper_bound), which skips any buffered |
| // sample whose key equals the incoming sample's. SampleMap's decode-order |
| // map is a unique-key std::map, so trackBuffer.addSample() silently drops |
| // the incoming sample if the existing sample at that key is not explicitly |
| // erased first. The 205636@main "samplesWithHigherDecodeTimes" block in |
| // processMediaSample catches the equal-key sample via findSamplesBetween- |
| // DecodeKeys (lower_bound inclusive-begin) and marks it for removal; if |
| // that block is absent the equal-key sample is stranded and the incoming |
| // sample is lost. |
| // |
| // Scenario (timescale=1000 ms): |
| // Seg 1 has five samples at DTS/PTS = 0, 100, 200, 300, 400, all dur=100, |
| // with sync at 0, 200, 400 and non-sync at 100, 300. After seg 1, buffer = |
| // [gen1@0, gen1@100, gen1@200, gen1@300, gen1@400], highestPT=500, |
| // lastDTS=400. |
| // |
| // Seg 2 is appended as two separate media segments (two appendBuffer calls) |
| // so their baseDecodeTime fields can be set independently: |
| // |
| // Fragment 2A (baseDecodeTime=0): two samples, |
| // (0, 0, dur=100, sync), |
| // (100, 100, dur=101, non-sync). |
| // The second sample's dur=101 pushes highestPT to 201 (=100+101). During |
| // its own step-1.14-second pass, eraseEnd = pts+dur-1ms = 200, so gen1@200 |
| // is outside the erase range [100, 200) and survives. |
| // |
| // Fragment 2B (baseDecodeTime=200): single sample |
| // (200, 200, dur=120, sync). |
| // For this incoming sync, step-1.14-second's range is |
| // [eraseBegin=highestPT=201, eraseEnd=200+120-1=319); |
| // gen1@200 at pts=200 is BELOW eraseBegin=201 and is not caught. The |
| // step-1.14 cascade does upper_bound((200,200)) = gen1@300 (skipping the |
| // equal-key gen1@200), erases gen1@300, and the step-1.15 dependent sweep |
| // runs on erasedSamples={gen1@300}. |
| // |
| // The 2018 block then looks for samples whose decode key is in the range |
| // [(200,200), erasedSamples.begin()->first=(300,300)) via lower_bound |
| // inclusive-begin: it finds gen1@200 and adds it to the dependent set. |
| // With the block: gen1@200 is evicted and the gen2B incoming sample |
| // inserts successfully with dur=120. Without the block: gen1@200 stays |
| // and the unique-key std::map insert of gen2B is a no-op; the sample at |
| // DTS=200 retains seg 1's dur=100. |
| // |
| // Detection: find the sample with DTS=0.200000 in the dump output of |
| // internals.bufferedSamplesForTrackId and check whether its duration |
| // prints as 0.120000 (seg 2B — block present) or 0.100000 (seg 1 — |
| // block absent, sample silently dropped). |
| |
| let source; |
| let sourceBuffer; |
| let init; |
| let segment1; |
| let segment2a; |
| let segment2b; |
| let bufferedSamples; |
| |
| async function runTest() { |
| findMediaElement(); |
| if (!MediaSource.isTypeSupported(MP4.VIDEO_TYPE)) { |
| failTest(`${MP4.VIDEO_TYPE} is not supported`); |
| return; |
| } |
| source = new MediaSource(); |
| run('video.src = URL.createObjectURL(source)'); |
| await waitFor(source, 'sourceopen'); |
| run(`sourceBuffer = source.addSourceBuffer('${MP4.VIDEO_TYPE}')`); |
| |
| init = MP4.initSegment({ |
| timescale: 1000, |
| tracks: [{ id: 1, type: 'video', timescale: 1000 }], |
| }); |
| segment1 = MP4.mediaSegment({ |
| sequenceNumber: 1, |
| tracks: [{ id: 1, type: 'video', baseDecodeTime: 0, samples: [ |
| { duration: 100, compositionTimeOffset: 0, isSync: true }, // DTS=0 |
| { duration: 100, compositionTimeOffset: 0, isSync: false }, // DTS=100 |
| { duration: 100, compositionTimeOffset: 0, isSync: true }, // DTS=200 ← target |
| { duration: 100, compositionTimeOffset: 0, isSync: false }, // DTS=300 |
| { duration: 100, compositionTimeOffset: 0, isSync: true }, // DTS=400 |
| ]}], |
| }); |
| segment2a = MP4.mediaSegment({ |
| sequenceNumber: 2, |
| tracks: [{ id: 1, type: 'video', baseDecodeTime: 0, samples: [ |
| { duration: 100, compositionTimeOffset: 0, isSync: true }, // DTS=0 |
| { duration: 101, compositionTimeOffset: 0, isSync: false }, // DTS=100, pushes highestPT=201 |
| ]}], |
| }); |
| segment2b = MP4.mediaSegment({ |
| sequenceNumber: 3, |
| tracks: [{ id: 1, type: 'video', baseDecodeTime: 200, samples: [ |
| { duration: 120, compositionTimeOffset: 0, isSync: true }, // DTS=200, equal-key incoming |
| ]}], |
| }); |
| |
| run('sourceBuffer.appendBuffer(MP4.concat(init, segment1))'); |
| await waitFor(sourceBuffer, 'updateend'); |
| run('sourceBuffer.appendBuffer(segment2a)'); |
| await waitFor(sourceBuffer, 'updateend'); |
| run('sourceBuffer.appendBuffer(segment2b)'); |
| await waitFor(sourceBuffer, 'updateend'); |
| |
| bufferedSamples = await internals.bufferedSamplesForTrackId(sourceBuffer, 1); |
| bufferedSamples.forEach(consoleWrite); |
| |
| window.sampleAt200Dts = bufferedSamples.find(s => /DTS\(\{[^}]*= 0\.200000\}\)/.test(s)); |
| window.sampleAt200Found = sampleAt200Dts !== undefined; |
| testExpected('sampleAt200Found', true); |
| window.hasSeg2Duration = sampleAt200Dts !== undefined && /duration\(\{[^}]*= 0\.120000\}\)/.test(sampleAt200Dts); |
| testExpected('hasSeg2Duration', true); |
| |
| endTest(); |
| } |
| </script> |
| </head> |
| <body onload="runTest()"> |
| <video></video> |
| </body> |
| </html> |
