From 49b655d3e1937018c46ed7f6a62e1157b247e426 Mon Sep 17 00:00:00 2001 From: Carl Hetherington Date: Mon, 1 Feb 2021 17:46:22 +0100 Subject: [PATCH] Use a predictable RNG when adding noise to low-bitrate images. The recovery code assumes that encoding a given frame from the same data will always give the same output; it always encodes frame 0 again to set things up properly and if that frame is a different size to the previous run everything breaks. --- src/lib/dcp_video.cc | 22 ++++++++++++-------- src/lib/rng.cc | 42 ++++++++++++++++++++++++++++++++++++++ src/lib/rng.h | 44 ++++++++++++++++++++++++++++++++++++++++ src/lib/wscript | 1 + test/torture_test.cc | 14 +++++++------ test/video_level_test.cc | 14 ++++++------- 6 files changed, 116 insertions(+), 21 deletions(-) create mode 100644 src/lib/rng.cc create mode 100644 src/lib/rng.h diff --git a/src/lib/dcp_video.cc b/src/lib/dcp_video.cc index 6bbd0d423..1f9f76771 100644 --- a/src/lib/dcp_video.cc +++ b/src/lib/dcp_video.cc @@ -1,5 +1,5 @@ /* - Copyright (C) 2012-2016 Carl Hetherington + Copyright (C) 2012-2021 Carl Hetherington This file is part of DCP-o-matic. @@ -18,6 +18,7 @@ */ + /** @file src/dcp_video_frame.cc * @brief A single frame of video destined for a DCP. * @@ -28,17 +29,19 @@ * of images that require encoding. */ -#include "dcp_video.h" + +#include "compose.hpp" #include "config.h" -#include "exceptions.h" -#include "encode_server_description.h" +#include "cross.h" +#include "dcp_video.h" +#include "dcpomatic_log.h" #include "dcpomatic_socket.h" +#include "encode_server_description.h" +#include "exceptions.h" #include "image.h" #include "log.h" -#include "dcpomatic_log.h" -#include "cross.h" #include "player_video.h" -#include "compose.hpp" +#include "rng.h" #include "warnings.h" #include #include @@ -143,6 +146,8 @@ DCPVideo::encode_locally () break; } + LOG_GENERAL (N_("Frame %1 encoded size was small (%2); adding noise at level %3"), _index, enc.size(), noise_amount); + /* The JPEG2000 is too low-bitrate for some decoders DSS200 so add some noise * and try again. This is slow but hopefully won't happen too often. We have to do * convert_to_xyz() again because compress_j2k() corrupts its xyz parameter. @@ -151,10 +156,11 @@ DCPVideo::encode_locally () xyz = convert_to_xyz (_frame, boost::bind(&Log::dcp_log, dcpomatic_log.get(), _1, _2)); auto size = xyz->size (); auto pixels = size.width * size.height; + dcpomatic::RNG rng(42); for (auto c = 0; c < 3; ++c) { auto p = xyz->data(c); for (auto i = 0; i < pixels; ++i) { - *p = std::min(4095, std::max(0, *p + rand() % noise_amount)); + *p = std::min(4095, std::max(0, *p + (rng.get() % noise_amount))); ++p; } } diff --git a/src/lib/rng.cc b/src/lib/rng.cc new file mode 100644 index 000000000..3fc41725d --- /dev/null +++ b/src/lib/rng.cc @@ -0,0 +1,42 @@ +/* + Copyright (C) 2020 Carl Hetherington + + This file is part of DCP-o-matic. + + DCP-o-matic is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + DCP-o-matic is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with DCP-o-matic. If not, see . + +*/ + + +#include "rng.h" +#include + + +using namespace dcpomatic; + + +RNG::RNG (int32_t seed) + : _state (static_cast(seed)) +{ + +} + + +int32_t RNG::get () +{ + uint32_t const b = ((_state >> 0) ^ (_state >> 1) ^ (_state >> 2) ^ (_state >> 7)); + _state = (_state >> 1) | (b << 23); + return static_cast(_state); +} + diff --git a/src/lib/rng.h b/src/lib/rng.h new file mode 100644 index 000000000..f3349ce9b --- /dev/null +++ b/src/lib/rng.h @@ -0,0 +1,44 @@ +/* + Copyright (C) 2020 Carl Hetherington + + This file is part of DCP-o-matic. + + DCP-o-matic is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + DCP-o-matic is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with DCP-o-matic. If not, see . + +*/ + + +#include + + +namespace dcpomatic { + + +/** @class RNG + * @brief Linear-feedback random number generator + */ +class RNG +{ +public: + RNG (int32_t seed); + + int32_t get (); + +private: + uint32_t _state; +}; + + +} + diff --git a/src/lib/wscript b/src/lib/wscript index bff3382e0..1b45152a4 100644 --- a/src/lib/wscript +++ b/src/lib/wscript @@ -144,6 +144,7 @@ sources = """ render_text.cc resampler.cc rgba.cc + rng.cc scoped_temporary.cc scp_uploader.cc screen.cc diff --git a/test/torture_test.cc b/test/torture_test.cc index 232435363..434ed0b5e 100644 --- a/test/torture_test.cc +++ b/test/torture_test.cc @@ -234,7 +234,7 @@ BOOST_AUTO_TEST_CASE (torture_test1) shared_ptr picture_reader = picture->start_read (); - /* First 5 * 24 = 120 frames should be black */ + /* First 5 * 24 = 120 frames should be black, possibly with a little noise to raise the bitrate */ shared_ptr ref; for (int i = 0; i < 120; ++i) { @@ -242,15 +242,17 @@ BOOST_AUTO_TEST_CASE (torture_test1) shared_ptr image = fr->xyz_image (); dcp::Size const size = image->size (); if (i == 0) { + /* Check the first frame pixel by pixel... */ for (int c = 0; c < 3; ++c) { for (int y = 0; y < size.height; ++y) { for (int x = 0; x < size.width; ++x) { - BOOST_REQUIRE_EQUAL (image->data(c)[y * size.height + x], 0); + BOOST_REQUIRE (image->data(c)[y * size.height + x] <= 3); } } } ref = image; } else { + /* ... then all the others should be the same */ for (int c = 0; c < 3; ++c) { BOOST_REQUIRE_MESSAGE ( memcmp (image->data(c), ref->data(c), size.width * size.height * sizeof(int)) == 0, @@ -260,7 +262,7 @@ BOOST_AUTO_TEST_CASE (torture_test1) } } - /* Then 24 red */ + /* Then 24 red, perhaps also with some noise */ for (int i = 120; i < 144; ++i) { shared_ptr fr = picture_reader->get_frame (i); @@ -270,15 +272,15 @@ BOOST_AUTO_TEST_CASE (torture_test1) for (int y = 0; y < size.height; ++y) { for (int x = 0; x < size.width; ++x) { BOOST_REQUIRE_MESSAGE ( - abs(image->data(0)[y * size.height + x] - 2808) <= 2, + abs(image->data(0)[y * size.height + x] - 2808) <= 5, "failed on frame " << i << " with image data " << image->data(0)[y * size.height + x] ); BOOST_REQUIRE_MESSAGE ( - abs(image->data(1)[y * size.height + x] - 2176) <= 2, + abs(image->data(1)[y * size.height + x] - 2176) <= 5, "failed on frame " << i << " with image data " << image->data(1)[y * size.height + x] ); BOOST_REQUIRE_MESSAGE ( - abs(image->data(2)[y * size.height + x] - 865) <= 2, + abs(image->data(2)[y * size.height + x] - 865) <= 5, "failed on frame " << i << " with image data " << image->data(2)[y * size.height + x] ); } diff --git a/test/video_level_test.cc b/test/video_level_test.cc index 2461bb9b3..0de6e17b3 100644 --- a/test/video_level_test.cc +++ b/test/video_level_test.cc @@ -438,7 +438,7 @@ BOOST_AUTO_TEST_CASE (movie_V_to_dcp) pair range = dcp_range (movie_V("movie_V_to_dcp")); /* Video range has been correctly expanded to full for the DCP */ BOOST_CHECK_EQUAL (range.first, 0); - BOOST_CHECK_EQUAL (range.second, 4082); + BOOST_CHECK_EQUAL (range.second, 4085); } @@ -448,8 +448,8 @@ BOOST_AUTO_TEST_CASE (movie_VoF_to_dcp) /* We said that video range data was really full range, so here we are in the DCP * with video-range data. */ - BOOST_CHECK_EQUAL (range.first, 350); - BOOST_CHECK_EQUAL (range.second, 3832); + BOOST_CHECK_EQUAL (range.first, 348); + BOOST_CHECK_EQUAL (range.second, 3833); } @@ -458,7 +458,7 @@ BOOST_AUTO_TEST_CASE (movie_F_to_dcp) pair range = dcp_range (movie_F("movie_F_to_dcp")); /* The nearly-full-range of the input has been preserved */ BOOST_CHECK_EQUAL (range.first, 0); - BOOST_CHECK_EQUAL (range.second, 4082); + BOOST_CHECK_EQUAL (range.second, 4085); } @@ -475,15 +475,15 @@ BOOST_AUTO_TEST_CASE (image_F_to_dcp) { pair range = dcp_range (image_F("image_F_to_dcp")); BOOST_CHECK_EQUAL (range.first, 0); - BOOST_CHECK_EQUAL (range.second, 4081); + BOOST_CHECK_EQUAL (range.second, 4085); } BOOST_AUTO_TEST_CASE (image_FoV_to_dcp) { pair range = dcp_range (image_FoV("image_FoV_to_dcp")); - BOOST_CHECK_EQUAL (range.first, 431); - BOOST_CHECK_EQUAL (range.second, 4012); + BOOST_CHECK_EQUAL (range.first, 429); + BOOST_CHECK_EQUAL (range.second, 4014); } -- 2.30.2