Fix: Custom audio filters and loudnorm do not work with ffmpeg enabled by carpelli · Pull Request #150 · Ajatt-Tools/mpvacious

carpelli · 2025-09-21T17:01:22Z

Fixes a bug in the ffmpeg filter processing where filter options are never actually passed to to the ffmpeg command. As a consequence, both user-provided filters and the loudnorm processing did not work.

The bug is caused by code that seems to assume reference semantics for strings, whereas Lua strings are immutable:

mpvacious/encoder/encoder.lua

Lines 279 to 299 in 86ab104

    
           ffmpeg.append_user_audio_args = function(args) 
        
               local new_args = {} 
        
               local filters = '' 
        
               separate_filters(filters, new_args, args) 
        
               if self.config.tie_volumes then 
        
                   add_filter(filters, string.format("volume=%.1f", mp.get_property_native('volume') / 100.0)) 
        
               end 
        
               local user_args = {} 
        
               for arg in string.gmatch(self.config.ffmpeg_audio_args, "%S+") do 
        
                   table.insert(user_args, arg) 
        
               end 
        
               separate_filters(filters, new_args, user_args) 
        
               if #filters > 0 then 
        
                   table.insert(new_args, '-af') 
        
                   table.insert(new_args, filters) 
        
               end 
        
               return new_args 
        
           end

Note that the filters string is not updated and remains empty.

Fix a bug in the ffmpeg filter processing where the `filters` string was never actually updated and remained empty (lua strings are immutable).

tatsumoto-ren · 2025-09-21T17:28:58Z

Makes sense, thanks.

Fix filter processing with ffmpeg

d136726

Fix a bug in the ffmpeg filter processing where the `filters` string was never actually updated and remained empty (lua strings are immutable).

tatsumoto-ren merged commit 2558235 into Ajatt-Tools:master Sep 21, 2025

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Fix: Custom audio filters and loudnorm do not work with ffmpeg enabled#150

Fix: Custom audio filters and loudnorm do not work with ffmpeg enabled#150
tatsumoto-ren merged 1 commit intoAjatt-Tools:masterfrom
carpelli:ffmpeg-filter-bug

carpelli commented Sep 21, 2025

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tatsumoto-ren commented Sep 21, 2025

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	ffmpeg.append_user_audio_args = function(args)
	local new_args = {}
	local filters = ''

	separate_filters(filters, new_args, args)
	if self.config.tie_volumes then
	add_filter(filters, string.format("volume=%.1f", mp.get_property_native('volume') / 100.0))
	end

	local user_args = {}
	for arg in string.gmatch(self.config.ffmpeg_audio_args, "%S+") do
	table.insert(user_args, arg)
	end
	separate_filters(filters, new_args, user_args)

	if #filters > 0 then
	table.insert(new_args, '-af')
	table.insert(new_args, filters)
	end
	return new_args
	end

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carpelli commented Sep 21, 2025

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tatsumoto-ren commented Sep 21, 2025

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