From 64c2ad7d6ec6cf7a1e05bd19b21d20f2a2aa6bfa Mon Sep 17 00:00:00 2001 From: KongQun Yang Date: Wed, 4 Apr 2018 16:17:59 -0700 Subject: [PATCH] Support removing segments outside of live window in DASH Issue: #223 Change-Id: Ie2d98a8f1553862532f1bdd074ca022d8904f0ea --- packager/media/base/muxer_util.h | 4 +- packager/mpd/base/representation.cc | 36 ++++++-- packager/mpd/base/representation.h | 7 ++ packager/mpd/base/representation_unittest.cc | 86 ++++++++++++++++++++ packager/mpd/public/mpd_params.h | 7 ++ 5 files changed, 129 insertions(+), 11 deletions(-) diff --git a/packager/media/base/muxer_util.h b/packager/media/base/muxer_util.h index 9bc936a902..43aa0177a2 100644 --- a/packager/media/base/muxer_util.h +++ b/packager/media/base/muxer_util.h @@ -11,9 +11,7 @@ #include -#include - -#include "packager/media/base/key_source.h" +#include "packager/status.h" namespace shaka { namespace media { diff --git a/packager/mpd/base/representation.cc b/packager/mpd/base/representation.cc index 4bf9861b87..ab44094d29 100644 --- a/packager/mpd/base/representation.cc +++ b/packager/mpd/base/representation.cc @@ -9,6 +9,8 @@ #include #include "packager/base/logging.h" +#include "packager/file/file.h" +#include "packager/media/base/muxer_util.h" #include "packager/mpd/base/mpd_options.h" #include "packager/mpd/base/mpd_utils.h" #include "packager/mpd/base/xml/xml_node.h" @@ -93,8 +95,8 @@ uint64_t LatestSegmentStartTime(const std::list& segments) { // Given |timeshift_limit|, finds out the number of segments that are no longer // valid and should be removed from |segment_info|. -int SearchTimedOutRepeatIndex(uint64_t timeshift_limit, - const SegmentInfo& segment_info) { +uint64_t SearchTimedOutRepeatIndex(uint64_t timeshift_limit, + const SegmentInfo& segment_info) { DCHECK_LE(timeshift_limit, LastSegmentEndTime(segment_info)); if (timeshift_limit < segment_info.start_time) return 0; @@ -427,34 +429,52 @@ void Representation::SlideWindow() { // looking at the very last segment's end time. std::list::iterator first = segment_infos_.begin(); std::list::iterator last = first; - size_t num_segments_removed = 0; for (; last != segment_infos_.end(); ++last) { const uint64_t last_segment_end_time = LastSegmentEndTime(*last); if (timeshift_limit < last_segment_end_time) break; - num_segments_removed += last->repeat + 1; + RemoveSegments(last->start_time, last->duration, last->repeat + 1); + start_number_ += last->repeat + 1; } segment_infos_.erase(first, last); - start_number_ += num_segments_removed; // Now some segment in the first SegmentInfo should be left in the list. SegmentInfo* first_segment_info = &segment_infos_.front(); DCHECK_LE(timeshift_limit, LastSegmentEndTime(*first_segment_info)); // Identify which segments should still be in the SegmentInfo. - const int repeat_index = + const uint64_t repeat_index = SearchTimedOutRepeatIndex(timeshift_limit, *first_segment_info); - CHECK_GE(repeat_index, 0); if (repeat_index == 0) return; + RemoveSegments(first_segment_info->start_time, first_segment_info->duration, + repeat_index); + first_segment_info->start_time = first_segment_info->start_time + first_segment_info->duration * repeat_index; - first_segment_info->repeat = first_segment_info->repeat - repeat_index; start_number_ += repeat_index; } +void Representation::RemoveSegments(uint64_t start_time, + uint64_t duration, + uint64_t num_segments) { + if (mpd_options_.mpd_params.preserved_segments_outside_live_window == 0) + return; + + for (size_t i = 0; i < num_segments; ++i) { + segments_to_be_removed_.push_back(media::GetSegmentName( + media_info_.segment_template(), start_time + i * duration, + start_number_ - 1 + i, media_info_.bandwidth())); + } + while (segments_to_be_removed_.size() > + mpd_options_.mpd_params.preserved_segments_outside_live_window) { + File::Delete(segments_to_be_removed_.front().c_str()); + segments_to_be_removed_.pop_front(); + } +} + std::string Representation::GetVideoMimeType() const { return GetMimeType("video", media_info_.container_type()); } diff --git a/packager/mpd/base/representation.h b/packager/mpd/base/representation.h index 70ba85dd01..6b8899b0d7 100644 --- a/packager/mpd/base/representation.h +++ b/packager/mpd/base/representation.h @@ -188,6 +188,11 @@ class Representation { // |start_number_| by the number of segments removed. void SlideWindow(); + // Remove |num_segments| starting from |start_time| with |duration|. + void RemoveSegments(uint64_t start_time, + uint64_t duration, + uint64_t num_segments); + // Note: Because 'mimeType' is a required field for a valid MPD, these return // strings. std::string GetVideoMimeType() const; @@ -200,6 +205,8 @@ class Representation { std::list content_protection_elements_; // TODO(kqyang): Address sliding window issue with multiple periods. std::list segment_infos_; + // A temporary list to hold the file names of segments to be removed. + std::list segments_to_be_removed_; const uint32_t id_; std::string mime_type_; diff --git a/packager/mpd/base/representation_unittest.cc b/packager/mpd/base/representation_unittest.cc index abfa8c79ef..241b1fb26b 100644 --- a/packager/mpd/base/representation_unittest.cc +++ b/packager/mpd/base/representation_unittest.cc @@ -11,6 +11,8 @@ #include #include "packager/base/strings/stringprintf.h" +#include "packager/file/file.h" +#include "packager/file/file_closer.h" #include "packager/mpd/base/mpd_options.h" #include "packager/mpd/test/mpd_builder_test_helper.h" #include "packager/mpd/test/xml_compare.h" @@ -22,6 +24,12 @@ namespace { const uint32_t kAnyRepresentationId = 1; +bool SegmentDeleted(const std::string& segment_name) { + std::unique_ptr file_closer( + File::Open(segment_name.c_str(), "r")); + return file_closer.get() == nullptr; +} + class MockRepresentationStateChangeListener : public RepresentationStateChangeListener { public: @@ -1006,4 +1014,82 @@ TEST_F(TimeShiftBufferDepthTest, ManySegments) { expected_s_element, kDefaultStartNumber + kExpectedRemovedSegments))); } +TEST_F(TimeShiftBufferDepthTest, DeleteSegmentsOutsideOfLiveWindow) { + const char kSegmentTemplate[] = "memory://$Number$.mp4"; + const char kStringPrintTemplate[] = "memory://%d.mp4"; + + // Create 100 files with the template. + for (int i = 1; i <= 100; ++i) { + File::WriteStringToFile(base::StringPrintf(kStringPrintTemplate, i).c_str(), + "dummy content"); + } + + MediaInfo media_info = ConvertToMediaInfo(GetDefaultMediaInfo()); + media_info.set_segment_template(kSegmentTemplate); + representation_ = + CreateRepresentation(media_info, kAnyRepresentationId, NoListener()); + ASSERT_TRUE(representation_->Init()); + + const int kTimeShiftBufferDepth = 2; + const int kNumPreservedSegmentsOutsideLiveWindow = 3; + const int kMaxNumSegmentsAvailable = + kTimeShiftBufferDepth + 1 + kNumPreservedSegmentsOutsideLiveWindow; + + mutable_mpd_options()->mpd_params.time_shift_buffer_depth = + kTimeShiftBufferDepth; + mutable_mpd_options()->mpd_params.preserved_segments_outside_live_window = + kNumPreservedSegmentsOutsideLiveWindow; + + const uint64_t kInitialStartTime = 0; + const uint64_t kDuration = kDefaultTimeScale; + const uint64_t kSize = 10; + const uint64_t kNoRepeat = 0; + + // Verify that no segments are deleted initially until there are more than + // |kMaxNumSegmentsAvailable| segments. + uint64_t next_start_time = kInitialStartTime; + int num_total_segments = 0; + int last_available_segment_index = 1; // No segments are deleted. + for (int i = 0; i < kMaxNumSegmentsAvailable; ++i) { + AddSegments(next_start_time, kDuration, kSize, kNoRepeat); + next_start_time += kDuration; + ++num_total_segments; + + EXPECT_FALSE(SegmentDeleted(base::StringPrintf( + kStringPrintTemplate, last_available_segment_index))); + } + + AddSegments(next_start_time, kDuration, kSize, kNoRepeat); + next_start_time += kDuration; + ++num_total_segments; + last_available_segment_index = 2; + + EXPECT_FALSE(SegmentDeleted( + base::StringPrintf(kStringPrintTemplate, last_available_segment_index))); + EXPECT_TRUE(SegmentDeleted(base::StringPrintf( + kStringPrintTemplate, last_available_segment_index - 1))); + + // Verify that there are exactly |kMaxNumSegmentsAvailable| segments + // remaining. + const uint64_t kRepeat = 10; + AddSegments(next_start_time, kDuration, kSize, kRepeat); + next_start_time += (kRepeat + 1) * kDuration; + num_total_segments += kRepeat + 1; + last_available_segment_index = + num_total_segments - kMaxNumSegmentsAvailable + 1; + + EXPECT_FALSE(SegmentDeleted( + base::StringPrintf(kStringPrintTemplate, last_available_segment_index))); + EXPECT_TRUE(SegmentDeleted(base::StringPrintf( + kStringPrintTemplate, last_available_segment_index - 1))); + + AddSegments(next_start_time, kDuration, kSize, kNoRepeat); + ++last_available_segment_index; + + EXPECT_FALSE(SegmentDeleted( + base::StringPrintf(kStringPrintTemplate, last_available_segment_index))); + EXPECT_TRUE(SegmentDeleted(base::StringPrintf( + kStringPrintTemplate, last_available_segment_index - 1))); +} + } // namespace shaka diff --git a/packager/mpd/public/mpd_params.h b/packager/mpd/public/mpd_params.h index 30aff9ea47..20ecd6152c 100644 --- a/packager/mpd/public/mpd_params.h +++ b/packager/mpd/public/mpd_params.h @@ -37,6 +37,13 @@ struct MpdParams { /// Set MPD@timeShiftBufferDepth attribute, which is the guaranteed duration /// of the time shifting buffer for 'dynamic' media presentations, in seconds. double time_shift_buffer_depth = 0; + /// Segments outside live window (defined by 'time_shift_buffer_depth' above) + /// are automatically removed except the latest number of segments defined by + /// this parameter. This is needed to accommodate latencies in various stages + /// of content serving pipeline, so that the segments stay accessible as they + /// may still be accessed by the player. + /// The segments are not removed if the value is zero. + size_t preserved_segments_outside_live_window = 0; /// UTCTimings. For dynamic MPD only. struct UtcTiming { std::string scheme_id_uri;