[feature] support processing of (many) more media types (#3090)

* initial work replacing our media decoding / encoding pipeline with ffprobe + ffmpeg

* specify the video codec to use when generating static image from emoji

* update go-storage library (fixes incompatibility after updating go-iotools)

* maintain image aspect ratio when generating a thumbnail for it

* update readme to show go-ffmpreg

* fix a bunch of media tests, move filesize checking to callers of media manager for more flexibility

* remove extra debug from error message

* fix up incorrect function signatures

* update PutFile to just use regular file copy, as changes are file is on separate partition

* fix remaining tests, remove some unneeded tests now we're working with ffmpeg/ffprobe

* update more tests, add more code comments

* add utilities to generate processed emoji / media outputs

* fix remaining tests

* add test for opus media file, add license header to utility cmds

* limit the number of concurrently available ffmpeg / ffprobe instances

* reduce number of instances

* further reduce number of instances

* fix envparsing test with configuration variables

* update docs and configuration with new media-{local,remote}-max-size variables

1 files changed, 0 insertions, 164 deletions

diff --git a/vendor/github.com/golang/geo/s2/metric.go b/vendor/github.com/golang/geo/s2/metric.go
deleted file mode 100644
index 53db3d317..000000000
--- a/vendor/github.com/golang/geo/s2/metric.go
+++ /dev/null
@@ -1,164 +0,0 @@
-// Copyright 2015 Google Inc. All rights reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package s2
-
-// This file implements functions for various S2 measurements.
-
-import "math"
-
-// A Metric is a measure for cells. It is used to describe the shape and size
-// of cells. They are useful for deciding which cell level to use in order to
-// satisfy a given condition (e.g. that cell vertices must be no further than
-// "x" apart). You can use the Value(level) method to compute the corresponding
-// length or area on the unit sphere for cells at a given level. The minimum
-// and maximum bounds are valid for cells at all levels, but they may be
-// somewhat conservative for very large cells (e.g. face cells).
-type Metric struct {
-	// Dim is either 1 or 2, for a 1D or 2D metric respectively.
-	Dim int
-	// Deriv is the scaling factor for the metric.
-	Deriv float64
-}
-
-// Defined metrics.
-// Of the projection methods defined in C++, Go only supports the quadratic projection.
-
-// Each cell is bounded by four planes passing through its four edges and
-// the center of the sphere. These metrics relate to the angle between each
-// pair of opposite bounding planes, or equivalently, between the planes
-// corresponding to two different s-values or two different t-values.
-var (
-	MinAngleSpanMetric = Metric{1, 4.0 / 3}
-	AvgAngleSpanMetric = Metric{1, math.Pi / 2}
-	MaxAngleSpanMetric = Metric{1, 1.704897179199218452}
-)
-
-// The width of geometric figure is defined as the distance between two
-// parallel bounding lines in a given direction. For cells, the minimum
-// width is always attained between two opposite edges, and the maximum
-// width is attained between two opposite vertices. However, for our
-// purposes we redefine the width of a cell as the perpendicular distance
-// between a pair of opposite edges. A cell therefore has two widths, one
-// in each direction. The minimum width according to this definition agrees
-// with the classic geometric one, but the maximum width is different. (The
-// maximum geometric width corresponds to MaxDiag defined below.)
-//
-// The average width in both directions for all cells at level k is approximately
-// AvgWidthMetric.Value(k).
-//
-// The width is useful for bounding the minimum or maximum distance from a
-// point on one edge of a cell to the closest point on the opposite edge.
-// For example, this is useful when growing regions by a fixed distance.
-var (
-	MinWidthMetric = Metric{1, 2 * math.Sqrt2 / 3}
-	AvgWidthMetric = Metric{1, 1.434523672886099389}
-	MaxWidthMetric = Metric{1, MaxAngleSpanMetric.Deriv}
-)
-
-// The edge length metrics can be used to bound the minimum, maximum,
-// or average distance from the center of one cell to the center of one of
-// its edge neighbors. In particular, it can be used to bound the distance
-// between adjacent cell centers along the space-filling Hilbert curve for
-// cells at any given level.
-var (
-	MinEdgeMetric = Metric{1, 2 * math.Sqrt2 / 3}
-	AvgEdgeMetric = Metric{1, 1.459213746386106062}
-	MaxEdgeMetric = Metric{1, MaxAngleSpanMetric.Deriv}
-
-	// MaxEdgeAspect is the maximum edge aspect ratio over all cells at any level,
-	// where the edge aspect ratio of a cell is defined as the ratio of its longest
-	// edge length to its shortest edge length.
-	MaxEdgeAspect = 1.442615274452682920
-
-	MinAreaMetric = Metric{2, 8 * math.Sqrt2 / 9}
-	AvgAreaMetric = Metric{2, 4 * math.Pi / 6}
-	MaxAreaMetric = Metric{2, 2.635799256963161491}
-)
-
-// The maximum diagonal is also the maximum diameter of any cell,
-// and also the maximum geometric width (see the comment for widths). For
-// example, the distance from an arbitrary point to the closest cell center
-// at a given level is at most half the maximum diagonal length.
-var (
-	MinDiagMetric = Metric{1, 8 * math.Sqrt2 / 9}
-	AvgDiagMetric = Metric{1, 2.060422738998471683}
-	MaxDiagMetric = Metric{1, 2.438654594434021032}
-
-	// MaxDiagAspect is the maximum diagonal aspect ratio over all cells at any
-	// level, where the diagonal aspect ratio of a cell is defined as the ratio
-	// of its longest diagonal length to its shortest diagonal length.
-	MaxDiagAspect = math.Sqrt(3)
-)
-
-// Value returns the value of the metric at the given level.
-func (m Metric) Value(level int) float64 {
-	return math.Ldexp(m.Deriv, -m.Dim*level)
-}
-
-// MinLevel returns the minimum level such that the metric is at most
-// the given value, or maxLevel (30) if there is no such level.
-//
-// For example, MinLevel(0.1) returns the minimum level such that all cell diagonal
-// lengths are 0.1 or smaller. The returned value is always a valid level.
-//
-// In C++, this is called GetLevelForMaxValue.
-func (m Metric) MinLevel(val float64) int {
-	if val < 0 {
-		return maxLevel
-	}
-
-	level := -(math.Ilogb(val/m.Deriv) >> uint(m.Dim-1))
-	if level > maxLevel {
-		level = maxLevel
-	}
-	if level < 0 {
-		level = 0
-	}
-	return level
-}
-
-// MaxLevel returns the maximum level such that the metric is at least
-// the given value, or zero if there is no such level.
-//
-// For example, MaxLevel(0.1) returns the maximum level such that all cells have a
-// minimum width of 0.1 or larger. The returned value is always a valid level.
-//
-// In C++, this is called GetLevelForMinValue.
-func (m Metric) MaxLevel(val float64) int {
-	if val <= 0 {
-		return maxLevel
-	}
-
-	level := math.Ilogb(m.Deriv/val) >> uint(m.Dim-1)
-	if level > maxLevel {
-		level = maxLevel
-	}
-	if level < 0 {
-		level = 0
-	}
-	return level
-}
-
-// ClosestLevel returns the level at which the metric has approximately the given
-// value. The return value is always a valid level. For example,
-// AvgEdgeMetric.ClosestLevel(0.1) returns the level at which the average cell edge
-// length is approximately 0.1.
-func (m Metric) ClosestLevel(val float64) int {
-	x := math.Sqrt2
-	if m.Dim == 2 {
-		x = 2
-	}
-	return m.MinLevel(x * val)
-}