[FFmpeg-devel] [PATCHv2 3/4] mkv: Export bounds and padding from spherical metadata

[Vittorio Giovara]

---
Updated according to James' review.
Please CC.
Vittorio

 libavformat/matroskadec.c              | 69 ++++++++++++++++++++++++++++++++--
 tests/ref/fate/matroska-spherical-mono |  6 ++-
 2 files changed, 71 insertions(+), 4 deletions(-)

diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index 7223e94..6fa961e 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -1913,16 +1913,65 @@ static int mkv_parse_video_projection(AVStream *st, const MatroskaTrack *track)
     AVSphericalMapping *spherical;
     enum AVSphericalProjection projection;
     size_t spherical_size;
+    size_t l, t, r, b;
+    size_t padding = 0;
     int ret;
+    GetByteContext gb;
+
+    bytestream2_init(&gb, track->video.projection.private.data,
+                     track->video.projection.private.size);
+
+    if (bytestream2_get_byte(&gb) != 0) {
+        av_log(NULL, AV_LOG_WARNING, "Unknown spherical metadata\n");
+        return 0;
+    }
+
+    bytestream2_skip(&gb, 3); // flags
 
     switch (track->video.projection.type) {
     case MATROSKA_VIDEO_PROJECTION_TYPE_EQUIRECTANGULAR:
-        projection = AV_SPHERICAL_EQUIRECTANGULAR;
+        if (track->video.projection.private.size == 0)
+            projection = AV_SPHERICAL_EQUIRECTANGULAR;
+        else if (track->video.projection.private.size == 20) {
+            t = bytestream2_get_be32(&gb);
+            b = bytestream2_get_be32(&gb);
+            l = bytestream2_get_be32(&gb);
+            r = bytestream2_get_be32(&gb);
+
+            if (b >= UINT_MAX - t || r >= UINT_MAX - l) {
+                av_log(NULL, AV_LOG_ERROR,
+                       "Invalid bounding rectangle coordinates "
+                       "%zu,%zu,%zu,%zu\n", l, t, r, b);
+                return AVERROR_INVALIDDATA;
+            }
+
+            if (l || t || r || b)
+                projection = AV_SPHERICAL_EQUIRECTANGULAR_TILE;
+            else
+                projection = AV_SPHERICAL_EQUIRECTANGULAR;
+        } else {
+            av_log(NULL, AV_LOG_ERROR, "Unknown spherical metadata\n");
+            return AVERROR_INVALIDDATA;
+        }
         break;
     case MATROSKA_VIDEO_PROJECTION_TYPE_CUBEMAP:
-        if (track->video.projection.private.size < 4)
+        if (track->video.projection.private.size < 4) {
+            av_log(NULL, AV_LOG_ERROR, "Missing projection private properties\n");
+            return AVERROR_INVALIDDATA;
+        } else if (track->video.projection.private.size == 12) {
+            uint32_t layout = bytestream2_get_be32(&gb);
+            if (layout == 0) {
+                projection = AV_SPHERICAL_CUBEMAP;
+            } else {
+                av_log(NULL, AV_LOG_WARNING,
+                       "Unknown spherical cubemap layout %"PRIu32"\n", layout);
+                return 0;
+            }
+            padding = bytestream2_get_be32(&gb);
+        } else {
+            av_log(NULL, AV_LOG_ERROR, "Unknown spherical metadata\n");
             return AVERROR_INVALIDDATA;
-        projection = AV_SPHERICAL_CUBEMAP;
+        }
         break;
     default:
         return 0;
@@ -1937,6 +1986,20 @@ static int mkv_parse_video_projection(AVStream *st, const MatroskaTrack *track)
     spherical->pitch = (int32_t)(track->video.projection.pitch * (1 << 16));
     spherical->roll  = (int32_t)(track->video.projection.roll  * (1 << 16));
 
+    spherical->padding = padding;
+
+    if (spherical->projection == AV_SPHERICAL_EQUIRECTANGULAR_TILE) {
+        /* conversion from 0.32 coordinates to pixels */
+        size_t orig_width  = (size_t) track->video.pixel_width  * UINT32_MAX / (UINT32_MAX - r - l);
+        size_t orig_height = (size_t) track->video.pixel_height * UINT32_MAX / (UINT32_MAX - b - t);
+
+        /* add a (UINT32_MAX - 1) to round up integer division */
+        spherical->bound_left   = (orig_width  * l + UINT32_MAX - 1) / UINT32_MAX;
+        spherical->bound_top    = (orig_height * t + UINT32_MAX - 1) / UINT32_MAX;
+        spherical->bound_right  = orig_width  - track->video.pixel_width  - spherical->bound_left;
+        spherical->bound_bottom = orig_height - track->video.pixel_height - spherical->bound_top;
+    }
+
     ret = av_stream_add_side_data(st, AV_PKT_DATA_SPHERICAL, (uint8_t *)spherical,
                                   spherical_size);
     if (ret < 0) {
diff --git a/tests/ref/fate/matroska-spherical-mono b/tests/ref/fate/matroska-spherical-mono
index 8048aff..a70d879 100644
--- a/tests/ref/fate/matroska-spherical-mono
+++ b/tests/ref/fate/matroska-spherical-mono
@@ -8,7 +8,11 @@ inverted=0
 [SIDE_DATA]
 side_data_type=Spherical Mapping
 side_data_size=56
-projection=equirectangular
+projection=tiled equirectangular
+bound_left=148
+bound_top=73
+bound_right=147
+bound_bottom=72
 yaw=45
 pitch=30
 roll=15
-- 
2.10.0