kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 1 | /* |
marpan@webrtc.org | f4c2de9 | 2012-06-05 21:07:28 +0000 | [diff] [blame] | 2 | * Copyright (c) 2012 The WebRTC project authors. All Rights Reserved. |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license |
| 5 | * that can be found in the LICENSE file in the root of the source |
| 6 | * tree. An additional intellectual property rights grant can be found |
| 7 | * in the file PATENTS. All contributing project authors may |
| 8 | * be found in the AUTHORS file in the root of the source tree. |
| 9 | */ |
kjellander@webrtc.org | 5b97b12 | 2011-12-08 07:42:18 +0000 | [diff] [blame] | 10 | |
Mirko Bonadei | 92ea95e | 2017-09-15 06:47:31 +0200 | [diff] [blame] | 11 | #ifndef MODULES_VIDEO_CODING_CODECS_TEST_VIDEOPROCESSOR_H_ |
| 12 | #define MODULES_VIDEO_CODING_CODECS_TEST_VIDEOPROCESSOR_H_ |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 13 | |
brandtr | b57f426 | 2017-08-30 06:29:51 -0700 | [diff] [blame] | 14 | #include <map> |
Erik Språng | 08127a9 | 2016-11-16 16:41:30 +0100 | [diff] [blame] | 15 | #include <memory> |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 16 | #include <string> |
brandtr | 17b958c | 2017-03-07 01:41:43 -0800 | [diff] [blame] | 17 | #include <vector> |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 18 | |
Mirko Bonadei | 92ea95e | 2017-09-15 06:47:31 +0200 | [diff] [blame] | 19 | #include "api/video/video_frame.h" |
| 20 | #include "common_video/libyuv/include/webrtc_libyuv.h" |
ssilkin | 612f858 | 2017-09-28 09:23:17 -0700 | [diff] [blame] | 21 | #include "modules/video_coding/codecs/h264/include/h264_globals.h" |
Mirko Bonadei | 92ea95e | 2017-09-15 06:47:31 +0200 | [diff] [blame] | 22 | #include "modules/video_coding/codecs/test/packet_manipulator.h" |
| 23 | #include "modules/video_coding/codecs/test/stats.h" |
Åsa Persson | 2d27fb5 | 2017-10-19 14:05:50 +0200 | [diff] [blame] | 24 | #include "modules/video_coding/codecs/test/test_config.h" |
Mirko Bonadei | 92ea95e | 2017-09-15 06:47:31 +0200 | [diff] [blame] | 25 | #include "modules/video_coding/include/video_codec_interface.h" |
| 26 | #include "modules/video_coding/utility/ivf_file_writer.h" |
| 27 | #include "modules/video_coding/utility/vp8_header_parser.h" |
| 28 | #include "modules/video_coding/utility/vp9_uncompressed_header_parser.h" |
| 29 | #include "rtc_base/buffer.h" |
| 30 | #include "rtc_base/checks.h" |
| 31 | #include "rtc_base/constructormagic.h" |
| 32 | #include "rtc_base/sequenced_task_checker.h" |
| 33 | #include "rtc_base/task_queue.h" |
| 34 | #include "test/testsupport/frame_reader.h" |
| 35 | #include "test/testsupport/frame_writer.h" |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 36 | |
| 37 | namespace webrtc { |
Erik Språng | 08127a9 | 2016-11-16 16:41:30 +0100 | [diff] [blame] | 38 | |
| 39 | class VideoBitrateAllocator; |
| 40 | |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 41 | namespace test { |
| 42 | |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 43 | // Handles encoding/decoding of video using the VideoEncoder/VideoDecoder |
| 44 | // interfaces. This is done in a sequential manner in order to be able to |
| 45 | // measure times properly. |
| 46 | // The class processes a frame at the time for the configured input file. |
| 47 | // It maintains state of where in the source input file the processing is at. |
| 48 | // |
| 49 | // Regarding packet loss: Note that keyframes are excluded (first or all |
| 50 | // depending on the ExcludeFrameTypes setting). This is because if key frames |
| 51 | // would be altered, all the following delta frames would be pretty much |
| 52 | // worthless. VP8 has an error-resilience feature that makes it able to handle |
| 53 | // packet loss in key non-first keyframes, which is why only the first is |
| 54 | // excluded by default. |
| 55 | // Packet loss in such important frames is handled on a higher level in the |
| 56 | // Video Engine, where signaling would request a retransmit of the lost packets, |
| 57 | // since they're so important. |
| 58 | // |
Åsa Persson | 7173cf2 | 2017-10-19 12:14:09 +0200 | [diff] [blame] | 59 | // Note this class is not thread safe and is meant for simple testing purposes. |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 60 | class VideoProcessor { |
| 61 | public: |
brandtr | c409552 | 2017-08-07 08:12:33 -0700 | [diff] [blame] | 62 | VideoProcessor(webrtc::VideoEncoder* encoder, |
| 63 | webrtc::VideoDecoder* decoder, |
| 64 | FrameReader* analysis_frame_reader, |
brandtr | c409552 | 2017-08-07 08:12:33 -0700 | [diff] [blame] | 65 | PacketManipulator* packet_manipulator, |
| 66 | const TestConfig& config, |
| 67 | Stats* stats, |
brandtr | c409552 | 2017-08-07 08:12:33 -0700 | [diff] [blame] | 68 | IvfFileWriter* encoded_frame_writer, |
| 69 | FrameWriter* decoded_frame_writer); |
| 70 | ~VideoProcessor(); |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 71 | |
brandtr | 8935d97 | 2017-09-06 01:53:22 -0700 | [diff] [blame] | 72 | // Reads a frame from the analysis frame reader and sends it to the encoder. |
| 73 | // When the encode callback is received, the encoded frame is sent to the |
| 74 | // decoder. The decoded frame is written to disk by the analysis frame writer. |
| 75 | // Objective video quality metrics can thus be calculated after the fact. |
| 76 | void ProcessFrame(); |
marpan@webrtc.org | f4c2de9 | 2012-06-05 21:07:28 +0000 | [diff] [blame] | 77 | |
brandtr | bdd555c | 2017-08-21 01:34:04 -0700 | [diff] [blame] | 78 | // Updates the encoder with target rates. Must be called at least once. |
Sergey Silkin | 1880c71 | 2018-01-17 11:36:27 +0100 | [diff] [blame] | 79 | void SetRates(size_t bitrate_kbps, size_t framerate_fps); |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 80 | |
| 81 | private: |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 82 | class VideoProcessorEncodeCompleteCallback |
pbos@webrtc.org | 7f7162a | 2013-07-30 15:18:31 +0000 | [diff] [blame] | 83 | : public webrtc::EncodedImageCallback { |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 84 | public: |
brandtr | c409552 | 2017-08-07 08:12:33 -0700 | [diff] [blame] | 85 | explicit VideoProcessorEncodeCompleteCallback( |
| 86 | VideoProcessor* video_processor) |
brandtr | c8c5905 | 2017-08-21 06:44:16 -0700 | [diff] [blame] | 87 | : video_processor_(video_processor), |
| 88 | task_queue_(rtc::TaskQueue::Current()) {} |
| 89 | |
Sergey Ulanov | 525df3f | 2016-08-02 17:46:41 -0700 | [diff] [blame] | 90 | Result OnEncodedImage( |
pbos@webrtc.org | 273a414 | 2014-12-01 15:23:21 +0000 | [diff] [blame] | 91 | const webrtc::EncodedImage& encoded_image, |
| 92 | const webrtc::CodecSpecificInfo* codec_specific_info, |
brandtr | 8bc9385 | 2017-02-15 05:19:51 -0800 | [diff] [blame] | 93 | const webrtc::RTPFragmentationHeader* fragmentation) override { |
brandtr | 8bc9385 | 2017-02-15 05:19:51 -0800 | [diff] [blame] | 94 | RTC_CHECK(codec_specific_info); |
brandtr | c8c5905 | 2017-08-21 06:44:16 -0700 | [diff] [blame] | 95 | |
| 96 | if (task_queue_ && !task_queue_->IsCurrent()) { |
brandtr | 4553562 | 2017-08-22 03:33:11 -0700 | [diff] [blame] | 97 | task_queue_->PostTask( |
| 98 | std::unique_ptr<rtc::QueuedTask>(new EncodeCallbackTask( |
| 99 | video_processor_, encoded_image, codec_specific_info))); |
brandtr | c8c5905 | 2017-08-21 06:44:16 -0700 | [diff] [blame] | 100 | return Result(Result::OK, 0); |
| 101 | } |
| 102 | |
brandtr | 8bc9385 | 2017-02-15 05:19:51 -0800 | [diff] [blame] | 103 | video_processor_->FrameEncoded(codec_specific_info->codecType, |
brandtr | 4553562 | 2017-08-22 03:33:11 -0700 | [diff] [blame] | 104 | encoded_image); |
brandtr | 8bc9385 | 2017-02-15 05:19:51 -0800 | [diff] [blame] | 105 | return Result(Result::OK, 0); |
| 106 | } |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 107 | |
| 108 | private: |
brandtr | c8c5905 | 2017-08-21 06:44:16 -0700 | [diff] [blame] | 109 | class EncodeCallbackTask : public rtc::QueuedTask { |
| 110 | public: |
| 111 | EncodeCallbackTask(VideoProcessor* video_processor, |
| 112 | const webrtc::EncodedImage& encoded_image, |
brandtr | 4553562 | 2017-08-22 03:33:11 -0700 | [diff] [blame] | 113 | const webrtc::CodecSpecificInfo* codec_specific_info) |
brandtr | c8c5905 | 2017-08-21 06:44:16 -0700 | [diff] [blame] | 114 | : video_processor_(video_processor), |
| 115 | buffer_(encoded_image._buffer, encoded_image._length), |
| 116 | encoded_image_(encoded_image), |
| 117 | codec_specific_info_(*codec_specific_info) { |
| 118 | encoded_image_._buffer = buffer_.data(); |
brandtr | c8c5905 | 2017-08-21 06:44:16 -0700 | [diff] [blame] | 119 | } |
| 120 | |
| 121 | bool Run() override { |
| 122 | video_processor_->FrameEncoded(codec_specific_info_.codecType, |
brandtr | 4553562 | 2017-08-22 03:33:11 -0700 | [diff] [blame] | 123 | encoded_image_); |
brandtr | c8c5905 | 2017-08-21 06:44:16 -0700 | [diff] [blame] | 124 | return true; |
| 125 | } |
| 126 | |
| 127 | private: |
| 128 | VideoProcessor* const video_processor_; |
| 129 | rtc::Buffer buffer_; |
| 130 | webrtc::EncodedImage encoded_image_; |
| 131 | const webrtc::CodecSpecificInfo codec_specific_info_; |
brandtr | c8c5905 | 2017-08-21 06:44:16 -0700 | [diff] [blame] | 132 | }; |
| 133 | |
brandtr | c409552 | 2017-08-07 08:12:33 -0700 | [diff] [blame] | 134 | VideoProcessor* const video_processor_; |
brandtr | c8c5905 | 2017-08-21 06:44:16 -0700 | [diff] [blame] | 135 | rtc::TaskQueue* const task_queue_; |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 136 | }; |
| 137 | |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 138 | class VideoProcessorDecodeCompleteCallback |
philipel | cce46fc | 2015-12-21 03:04:49 -0800 | [diff] [blame] | 139 | : public webrtc::DecodedImageCallback { |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 140 | public: |
brandtr | c409552 | 2017-08-07 08:12:33 -0700 | [diff] [blame] | 141 | explicit VideoProcessorDecodeCompleteCallback( |
| 142 | VideoProcessor* video_processor) |
brandtr | c8c5905 | 2017-08-21 06:44:16 -0700 | [diff] [blame] | 143 | : video_processor_(video_processor), |
| 144 | task_queue_(rtc::TaskQueue::Current()) {} |
| 145 | |
brandtr | 8bc9385 | 2017-02-15 05:19:51 -0800 | [diff] [blame] | 146 | int32_t Decoded(webrtc::VideoFrame& image) override { |
brandtr | c8c5905 | 2017-08-21 06:44:16 -0700 | [diff] [blame] | 147 | if (task_queue_ && !task_queue_->IsCurrent()) { |
| 148 | task_queue_->PostTask( |
| 149 | [this, image]() { video_processor_->FrameDecoded(image); }); |
| 150 | return 0; |
| 151 | } |
brandtr | 8bc9385 | 2017-02-15 05:19:51 -0800 | [diff] [blame] | 152 | video_processor_->FrameDecoded(image); |
| 153 | return 0; |
| 154 | } |
brandtr | c8c5905 | 2017-08-21 06:44:16 -0700 | [diff] [blame] | 155 | |
philipel | cce46fc | 2015-12-21 03:04:49 -0800 | [diff] [blame] | 156 | int32_t Decoded(webrtc::VideoFrame& image, |
| 157 | int64_t decode_time_ms) override { |
brandtr | 6bb8e0e | 2017-02-20 04:35:52 -0800 | [diff] [blame] | 158 | return Decoded(image); |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 159 | } |
brandtr | c8c5905 | 2017-08-21 06:44:16 -0700 | [diff] [blame] | 160 | |
brandtr | 6bb8e0e | 2017-02-20 04:35:52 -0800 | [diff] [blame] | 161 | void Decoded(webrtc::VideoFrame& image, |
sakal | cc452e1 | 2017-02-09 04:53:45 -0800 | [diff] [blame] | 162 | rtc::Optional<int32_t> decode_time_ms, |
| 163 | rtc::Optional<uint8_t> qp) override { |
brandtr | bea36fd | 2017-08-07 03:36:54 -0700 | [diff] [blame] | 164 | Decoded(image); |
sakal | cc452e1 | 2017-02-09 04:53:45 -0800 | [diff] [blame] | 165 | } |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 166 | |
| 167 | private: |
brandtr | c409552 | 2017-08-07 08:12:33 -0700 | [diff] [blame] | 168 | VideoProcessor* const video_processor_; |
brandtr | c8c5905 | 2017-08-21 06:44:16 -0700 | [diff] [blame] | 169 | rtc::TaskQueue* const task_queue_; |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 170 | }; |
brandtr | 8bc9385 | 2017-02-15 05:19:51 -0800 | [diff] [blame] | 171 | |
brandtr | bdd555c | 2017-08-21 01:34:04 -0700 | [diff] [blame] | 172 | // Invoked by the callback adapter when a frame has completed encoding. |
brandtr | 8bc9385 | 2017-02-15 05:19:51 -0800 | [diff] [blame] | 173 | void FrameEncoded(webrtc::VideoCodecType codec, |
brandtr | 4553562 | 2017-08-22 03:33:11 -0700 | [diff] [blame] | 174 | const webrtc::EncodedImage& encodedImage); |
brandtr | 8bc9385 | 2017-02-15 05:19:51 -0800 | [diff] [blame] | 175 | |
brandtr | bdd555c | 2017-08-21 01:34:04 -0700 | [diff] [blame] | 176 | // Invoked by the callback adapter when a frame has completed decoding. |
brandtr | 8bc9385 | 2017-02-15 05:19:51 -0800 | [diff] [blame] | 177 | void FrameDecoded(const webrtc::VideoFrame& image); |
| 178 | |
Åsa Persson | f0c4467 | 2017-10-24 16:03:39 +0200 | [diff] [blame] | 179 | void WriteDecodedFrameToFile(rtc::Buffer* buffer); |
| 180 | bool ExcludeFrame(const EncodedImage& encoded_image); |
| 181 | |
danilchap | 56359be | 2017-09-07 07:53:45 -0700 | [diff] [blame] | 182 | TestConfig config_ RTC_GUARDED_BY(sequence_checker_); |
brandtr | 07734a5 | 2017-08-08 08:35:53 -0700 | [diff] [blame] | 183 | |
brandtr | 8bc9385 | 2017-02-15 05:19:51 -0800 | [diff] [blame] | 184 | webrtc::VideoEncoder* const encoder_; |
| 185 | webrtc::VideoDecoder* const decoder_; |
brandtr | aebc61e | 2017-02-28 07:13:47 -0800 | [diff] [blame] | 186 | const std::unique_ptr<VideoBitrateAllocator> bitrate_allocator_; |
Sergey Silkin | 1880c71 | 2018-01-17 11:36:27 +0100 | [diff] [blame] | 187 | BitrateAllocation bitrate_allocation_ RTC_GUARDED_BY(sequence_checker_); |
brandtr | aebc61e | 2017-02-28 07:13:47 -0800 | [diff] [blame] | 188 | |
| 189 | // Adapters for the codec callbacks. |
brandtr | bdd555c | 2017-08-21 01:34:04 -0700 | [diff] [blame] | 190 | VideoProcessorEncodeCompleteCallback encode_callback_; |
| 191 | VideoProcessorDecodeCompleteCallback decode_callback_; |
brandtr | aebc61e | 2017-02-28 07:13:47 -0800 | [diff] [blame] | 192 | |
brandtr | 07734a5 | 2017-08-08 08:35:53 -0700 | [diff] [blame] | 193 | // Fake network. |
brandtr | aebc61e | 2017-02-28 07:13:47 -0800 | [diff] [blame] | 194 | PacketManipulator* const packet_manipulator_; |
brandtr | aebc61e | 2017-02-28 07:13:47 -0800 | [diff] [blame] | 195 | |
Sergey Silkin | 64eaa99 | 2017-11-17 14:47:32 +0100 | [diff] [blame] | 196 | // Input frames. Used as reference at frame quality evaluation. |
| 197 | // Async codecs might queue frames. To handle that we keep input frame |
| 198 | // and release it after corresponding coded frame is decoded and quality |
| 199 | // measurement is done. |
Sergey Silkin | 1880c71 | 2018-01-17 11:36:27 +0100 | [diff] [blame] | 200 | std::map<size_t, std::unique_ptr<VideoFrame>> input_frames_ |
Sergey Silkin | 64eaa99 | 2017-11-17 14:47:32 +0100 | [diff] [blame] | 201 | RTC_GUARDED_BY(sequence_checker_); |
| 202 | |
brandtr | b78bc75 | 2017-02-22 01:26:59 -0800 | [diff] [blame] | 203 | // These (mandatory) file manipulators are used for, e.g., objective PSNR and |
| 204 | // SSIM calculations at the end of a test run. |
| 205 | FrameReader* const analysis_frame_reader_; |
brandtr | aebc61e | 2017-02-28 07:13:47 -0800 | [diff] [blame] | 206 | |
brandtr | c287c80 | 2017-08-07 08:30:43 -0700 | [diff] [blame] | 207 | // These (optional) file writers are used to persistently store the encoded |
| 208 | // and decoded bitstreams. The purpose is to give the experimenter an option |
| 209 | // to subjectively evaluate the quality of the processing. Each frame writer |
| 210 | // is enabled by being non-null. |
brandtr | b78bc75 | 2017-02-22 01:26:59 -0800 | [diff] [blame] | 211 | IvfFileWriter* const encoded_frame_writer_; |
| 212 | FrameWriter* const decoded_frame_writer_; |
brandtr | 8bc9385 | 2017-02-15 05:19:51 -0800 | [diff] [blame] | 213 | |
brandtr | 8935d97 | 2017-09-06 01:53:22 -0700 | [diff] [blame] | 214 | // Keep track of inputed/encoded/decoded frames, so we can detect frame drops. |
Sergey Silkin | 1880c71 | 2018-01-17 11:36:27 +0100 | [diff] [blame] | 215 | size_t last_inputed_frame_num_ RTC_GUARDED_BY(sequence_checker_); |
| 216 | size_t last_encoded_frame_num_ RTC_GUARDED_BY(sequence_checker_); |
| 217 | size_t last_decoded_frame_num_ RTC_GUARDED_BY(sequence_checker_); |
| 218 | size_t num_encoded_frames_ RTC_GUARDED_BY(sequence_checker_); |
| 219 | size_t num_decoded_frames_ RTC_GUARDED_BY(sequence_checker_); |
brandtr | 17b958c | 2017-03-07 01:41:43 -0800 | [diff] [blame] | 220 | |
brandtr | b57f426 | 2017-08-30 06:29:51 -0700 | [diff] [blame] | 221 | // Store an RTP timestamp -> frame number map, since the timestamps are |
| 222 | // based off of the frame rate, which can change mid-test. |
Sergey Silkin | 1880c71 | 2018-01-17 11:36:27 +0100 | [diff] [blame] | 223 | std::map<size_t, size_t> rtp_timestamp_to_frame_num_ |
danilchap | 56359be | 2017-09-07 07:53:45 -0700 | [diff] [blame] | 224 | RTC_GUARDED_BY(sequence_checker_); |
brandtr | b57f426 | 2017-08-30 06:29:51 -0700 | [diff] [blame] | 225 | |
brandtr | 17b958c | 2017-03-07 01:41:43 -0800 | [diff] [blame] | 226 | // Keep track of if we have excluded the first key frame from packet loss. |
danilchap | 56359be | 2017-09-07 07:53:45 -0700 | [diff] [blame] | 227 | bool first_key_frame_has_been_excluded_ RTC_GUARDED_BY(sequence_checker_); |
brandtr | 17b958c | 2017-03-07 01:41:43 -0800 | [diff] [blame] | 228 | |
| 229 | // Keep track of the last successfully decoded frame, since we write that |
| 230 | // frame to disk when decoding fails. |
danilchap | 56359be | 2017-09-07 07:53:45 -0700 | [diff] [blame] | 231 | rtc::Buffer last_decoded_frame_buffer_ RTC_GUARDED_BY(sequence_checker_); |
brandtr | 8bc9385 | 2017-02-15 05:19:51 -0800 | [diff] [blame] | 232 | |
| 233 | // Statistics. |
brandtr | aebc61e | 2017-02-28 07:13:47 -0800 | [diff] [blame] | 234 | Stats* stats_; |
brandtr | c8c5905 | 2017-08-21 06:44:16 -0700 | [diff] [blame] | 235 | |
| 236 | rtc::SequencedTaskChecker sequence_checker_; |
brandtr | bdd555c | 2017-08-21 01:34:04 -0700 | [diff] [blame] | 237 | |
| 238 | RTC_DISALLOW_COPY_AND_ASSIGN(VideoProcessor); |
kjellander@webrtc.org | 35a1756 | 2011-10-06 06:44:54 +0000 | [diff] [blame] | 239 | }; |
| 240 | |
| 241 | } // namespace test |
| 242 | } // namespace webrtc |
| 243 | |
Mirko Bonadei | 92ea95e | 2017-09-15 06:47:31 +0200 | [diff] [blame] | 244 | #endif // MODULES_VIDEO_CODING_CODECS_TEST_VIDEOPROCESSOR_H_ |