Test: smaller steps when adding noise.

diff --git a/src/lib/dcp_video.cc b/src/lib/dcp_video.cc
index 18d7985c85c4e5ded2ca7839c6d1a8025f24037b..153f4997ed7dbdbaf14afe693a76ae0476fa7c1a 100644 (file)
--- a/src/lib/dcp_video.cc
+++ b/src/lib/dcp_video.cc
@@ -133,6 +133,7 @@ DCPVideo::encode_locally ()
 
        auto xyz = convert_to_xyz (_frame, boost::bind(&Log::dcp_log, dcpomatic_log.get(), _1, _2));
        int noise_amount = 2;
+       int pixel_skip = 16;
        while (true) {
                enc = dcp::compress_j2k (
                        xyz,
@@ -144,10 +145,11 @@ DCPVideo::encode_locally ()
                );
 
                if (enc.size() >= minimum_size) {
+                       LOG_GENERAL (N_("Frame %1 encoded size was OK (%2)"), _index, enc.size());
                        break;
                }
 
-               LOG_GENERAL (N_("Frame %1 encoded size was small (%2); adding noise at level %3"), _index, enc.size(), noise_amount);
+               LOG_GENERAL (N_("Frame %1 encoded size was small (%2); adding noise at level %3 with pixel skip %4"), _index, enc.size(), noise_amount, pixel_skip);
 
                /* The JPEG2000 is too low-bitrate for some decoders <cough>DSS200</cough> so add some noise
                 * and try again.  This is slow but hopefully won't happen too often.  We have to do
@@ -160,13 +162,18 @@ DCPVideo::encode_locally ()
                dcpomatic::RNG rng(42);
                for (auto c = 0; c < 3; ++c) {
                        auto p = xyz->data(c);
-                       for (auto i = 0; i < pixels; ++i) {
+                       auto e = xyz->data(c) + pixels;
+                       while (p < e) {
                                *p = std::min(4095, std::max(0, *p + (rng.get() % noise_amount)));
-                               ++p;
+                               p += pixel_skip;
                        }
                }
 
-               ++noise_amount;
+               if (pixel_skip > 1) {
+                       --pixel_skip;
+               } else {
+                       ++noise_amount;
+               }
                /* Something's gone badly wrong if this much noise doesn't help */
                DCPOMATIC_ASSERT (noise_amount < 16);
        }