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whippy-edition/lib/paperclip/transcoder.rb
Claire 166f6e4b50
Fix some media attachments being converted with too high framerates (#17619)
Video files with variable framerates are converted to constant framerate videos
and the output framerate picked by ffmpeg is based on the original file's
container framerate (which can be different from the average framerate).

This means that an input video with variable framerate with about 30 frames per
second on average, but a maximum of 120 fps will be converted to a constant 120
fps file, which won't be processed by other Mastodon servers.

This commit changes it so that input files with VFR and a maximum framerate
above the framerate threshold are converted to VFR files with the maximum frame
rate enforced.
2022-02-22 17:11:22 +01:00

117 lines
3.9 KiB
Ruby

# frozen_string_literal: true
module Paperclip
# This transcoder is only to be used for the MediaAttachment model
# to check when uploaded videos are actually gifv's
class Transcoder < Paperclip::Processor
def initialize(file, options = {}, attachment = nil)
super
@current_format = File.extname(@file.path)
@basename = File.basename(@file.path, @current_format)
@format = options[:format]
@time = options[:time] || 3
@passthrough_options = options[:passthrough_options]
@convert_options = options[:convert_options].dup
@vfr_threshold = options[:vfr_frame_rate_threshold]
end
def make
metadata = VideoMetadataExtractor.new(@file.path)
unless metadata.valid?
Paperclip.log("Unsupported file #{@file.path}")
return File.open(@file.path)
end
update_attachment_type(metadata)
update_options_from_metadata(metadata)
destination = Tempfile.new([@basename, @format ? ".#{@format}" : ''])
destination.binmode
@output_options = @convert_options[:output]&.dup || {}
@input_options = @convert_options[:input]&.dup || {}
case @format.to_s
when /jpg$/, /jpeg$/, /png$/, /gif$/
@input_options['ss'] = @time
@output_options['f'] = 'image2'
@output_options['vframes'] = 1
when 'mp4'
@output_options['acodec'] = 'aac'
@output_options['strict'] = 'experimental'
if high_vfr?(metadata) && !eligible_to_passthrough?(metadata)
@output_options['vsync'] = 'vfr'
@output_options['r'] = @vfr_threshold
end
end
command_arguments, interpolations = prepare_command(destination)
begin
command = Terrapin::CommandLine.new('ffmpeg', command_arguments.join(' '), logger: Paperclip.logger)
command.run(interpolations)
rescue Terrapin::ExitStatusError => e
raise Paperclip::Error, "Error while transcoding #{@basename}: #{e}"
rescue Terrapin::CommandNotFoundError
raise Paperclip::Errors::CommandNotFoundError, 'Could not run the `ffmpeg` command. Please install ffmpeg.'
end
destination
end
private
def prepare_command(destination)
command_arguments = ['-nostdin']
interpolations = {}
interpolation_keys = 0
@input_options.each_pair do |key, value|
interpolation_key = interpolation_keys
command_arguments << "-#{key} :#{interpolation_key}"
interpolations[interpolation_key] = value
interpolation_keys += 1
end
command_arguments << '-i :source'
interpolations[:source] = @file.path
@output_options.each_pair do |key, value|
interpolation_key = interpolation_keys
command_arguments << "-#{key} :#{interpolation_key}"
interpolations[interpolation_key] = value
interpolation_keys += 1
end
command_arguments << '-y :destination'
interpolations[:destination] = destination.path
[command_arguments, interpolations]
end
def update_options_from_metadata(metadata)
return unless eligible_to_passthrough?(metadata)
@format = @passthrough_options[:options][:format] || @format
@time = @passthrough_options[:options][:time] || @time
@convert_options = @passthrough_options[:options][:convert_options].dup
end
def high_vfr?(metadata)
@vfr_threshold && metadata.r_frame_rate && metadata.r_frame_rate > @vfr_threshold
end
def eligible_to_passthrough?(metadata)
@passthrough_options && @passthrough_options[:video_codecs].include?(metadata.video_codec) && @passthrough_options[:audio_codecs].include?(metadata.audio_codec) && @passthrough_options[:colorspaces].include?(metadata.colorspace)
end
def update_attachment_type(metadata)
@attachment.instance.type = MediaAttachment.types[:gifv] unless metadata.audio_codec
end
end
end