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-rw-r--r--activestorage/lib/active_storage/analyzer/video_analyzer.rb79
1 files changed, 79 insertions, 0 deletions
diff --git a/activestorage/lib/active_storage/analyzer/video_analyzer.rb b/activestorage/lib/active_storage/analyzer/video_analyzer.rb
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+++ b/activestorage/lib/active_storage/analyzer/video_analyzer.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+require "active_support/core_ext/hash/compact"
+
+module ActiveStorage
+ # Extracts the following from a video blob:
+ #
+ # * Width (pixels)
+ # * Height (pixels)
+ # * Duration (seconds)
+ # * Angle (degrees)
+ # * Aspect ratio
+ #
+ # Example:
+ #
+ # ActiveStorage::VideoAnalyzer.new(blob).metadata
+ # # => { width: 640, height: 480, duration: 5.0, angle: 0, aspect_ratio: [4, 3] }
+ #
+ # This analyzer requires the {ffmpeg}[https://www.ffmpeg.org] system library, which is not provided by Rails. You must
+ # install ffmpeg yourself to use this analyzer.
+ class Analyzer::VideoAnalyzer < Analyzer
+ def self.accept?(blob)
+ blob.video?
+ end
+
+ def metadata
+ { width: width, height: height, duration: duration, angle: angle, aspect_ratio: aspect_ratio }.compact
+ end
+
+ private
+ def width
+ Integer(video_stream["width"]) if video_stream["width"]
+ end
+
+ def height
+ Integer(video_stream["height"]) if video_stream["height"]
+ end
+
+ def duration
+ Float(video_stream["duration"]) if video_stream["duration"]
+ end
+
+ def angle
+ Integer(tags["rotate"]) if tags["rotate"]
+ end
+
+ def aspect_ratio
+ if descriptor = video_stream["display_aspect_ratio"]
+ descriptor.split(":", 2).collect(&:to_i)
+ end
+ end
+
+
+ def tags
+ @tags ||= video_stream["tags"] || {}
+ end
+
+ def video_stream
+ @video_stream ||= streams.detect { |stream| stream["codec_type"] == "video" } || {}
+ end
+
+ def streams
+ probe["streams"] || []
+ end
+
+ def probe
+ download_blob_to_tempfile { |file| probe_from(file) }
+ end
+
+ def probe_from(file)
+ IO.popen([ "ffprobe", "-print_format", "json", "-show_streams", "-v", "error", file.path ]) do |output|
+ JSON.parse(output.read)
+ end
+ rescue Errno::ENOENT
+ logger.info "Skipping video analysis because ffmpeg isn't installed"
+ {}
+ end
+ end
+end