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GitOrigin-RevId: 1237f560f10007d74f620349f9fe27b492f5faf6
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MediaPipe Team 2020-01-10 15:48:01 -08:00 committed by jqtang
parent ae6be10afe
commit a2823541e6
3 changed files with 30 additions and 8 deletions
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30
mediapipe/docs/autoflip.md
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@ -85,7 +85,7 @@ node {
node_options: {
[type.googleapis.com/mediapipe.PacketThinnerCalculatorOptions]: {
thinner_type: ASYNC
period: 500000
period: 200000
}
}
}
@ -215,7 +215,7 @@ node {
score_aggregation_type: CONSTANT
}
scene_camera_motion_analyzer_options: {
motion_stabilization_threshold_percent: 0.3
motion_stabilization_threshold_percent: 0.5
salient_point_bound: 0.499
}
padding_parameters: {
@ -278,7 +278,29 @@ the required features cannot be all covered (for example, when they are too
spread out in the video), AutoFlip will apply a padding effect to cover as much
salient content as possible. See an illustration below.
![graph is_required](images/autoflip_is_required.gif)
![graph is_required](images/autoflip_is_required.gif){width="600"}
### Stable vs Tracking Camera Motion
AutoFlip makes a decision on each scene whether to have the cropped viewpoint
follow an object or if the crop should remain stable (centered on detected
objects). The parameter `motion_stabilization_threshold_percent` value is used
to make the decision to track action or keep the camera stable. If, over the
duration of the scene, all detected focus objects remain within this ratio of
the frame (e.g. 0.5 = 50% or 1920 * .5 = 960 pixels on 1080p video) then the
camera is held steady. Otherwise the camera tracks activity within the frame.
### Snap To Center
For some scenes the camera viewpoint will remain stable at the center of
activity (see `motion_stabilization_threshold_percent` setting). In this case,
if the determined best stable viewpoint is within
`snap_center_max_distance_percent` of the frame's center the camera will be
shifted to be locked to the center of the frame. This setting is useful for
videos where the camera operator did a good job already centering content or if
titles and logos are expected to appear in the center of the frame. It may be
less useful on raw content where objects are not already well positioned on
screen.
### Visualization to Facilitate Debugging
@ -307,7 +329,7 @@ node {
score_aggregation_type: CONSTANT
}
scene_camera_motion_analyzer_options: {
motion_stabilization_threshold_percent: 0.3
motion_stabilization_threshold_percent: 0.5
salient_point_bound: 0.499
}
padding_parameters: {

4
mediapipe/examples/desktop/autoflip/autoflip_graph.pbtxt
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@ -35,7 +35,7 @@ node {
options: {
[mediapipe.PacketThinnerCalculatorOptions.ext]: {
thinner_type: ASYNC
period: 500000
period: 200000
}
}
}
@ -165,7 +165,7 @@ node {
score_aggregation_type: CONSTANT
}
scene_camera_motion_analyzer_options: {
motion_stabilization_threshold_percent: 0.3
motion_stabilization_threshold_percent: 0.5
salient_point_bound: 0.499
}
padding_parameters: {

4
mediapipe/examples/desktop/autoflip/autoflip_graph_development.pbtxt
View File

@ -35,7 +35,7 @@ node {
options: {
[mediapipe.PacketThinnerCalculatorOptions.ext]: {
thinner_type: ASYNC
period: 500000
period: 200000
}
}
}
@ -167,7 +167,7 @@ node {
score_aggregation_type: CONSTANT
}
scene_camera_motion_analyzer_options: {
motion_stabilization_threshold_percent: 0.3
motion_stabilization_threshold_percent: 0.5
salient_point_bound: 0.499
}
padding_parameters: {