FFMPEG Volume command argument limit

Context:

Trying to adjust volume in an audio file dynamically using volume filter, with commands. I want to frequently raise & lower volume in an audio file between 10 minutes and 60 minutes in length. Basically, trying to accomplish volume automation like Pro Tools / Ableton / Logic does, but within FFMPEG.

Constraints:

This must be done within using 1 ffmpeg command (part of a larger filter graph).

Work so far:

My first attempt is using a massive if command, nesting for subsequent volume raises and lowers. It works fine for my 10 minute audio file use cases at the moment.

Issue:

For a 15 minute audio file, with many fades, FFMPEG produces this errors that appear to be cutting off parts of the volume input filter.

Volume Input

volume='if(lt(t,0.500000),0.466667-t*0.533333,if(lt(t,37.165000),0.200000,if(lt(t,38.665000),t*0.533333-19.621333,if(lt(t,45.265000),1.000000,if(lt(t,46.765000),25.141333-t*0.533333,if(lt(t,64.200000),0.200000,if(lt(t,65.700000),t*0.533333-34.040000,if(lt(t,75.265000),1.000000,if(lt(t,76.765000),41.141333-t*0.533333,if(lt(t,80.580000),0.200000,if(lt(t,82.080000),t*0.533333-42.776000,if(lt(t,105.265000),1.000000,if(lt(t,106.765000),57.141333-t*0.533333,if(lt(t,117.015000),0.200000,if(lt(t,118.515000),t*0.533333-62.208000,if(lt(t,165.265000),1.000000,if(lt(t,166.765000),89.141333-t*0.533333,if(lt(t,173.600000),0.200000,if(lt(t,175.100000),t*0.533333-92.386667,if(lt(t,180.265000),1.000000,if(lt(t,181.765000),97.141333-t*0.533333,if(lt(t,195.160000),0.200000,if(lt(t,196.660000),t*0.533333-103.885333,if(lt(t,258.588750),1.000000,if(lt(t,260.088750),138.914000-t*0.533333,if(lt(t,263.693750),0.200000,if(lt(t,265.193750),t*0.533333-140.436667,if(lt(t,270.441250),1.000000,if(lt(t,271.941250),145.235333-t*0.533333,if(lt(t,296.705000),0.200000,if(lt(t,298.205000),t*0.533333-158.042667,if(lt(t,305.515000),1.000000,if(lt(t,307.015000),163.941333-t*0.533333,if(lt(t,310.810000),0.200000,if(lt(t,312.310000),t*0.533333-165.565333,if(lt(t,320.602500),1.000000,if(lt(t,322.102500),171.988000-t*0.533333,if(lt(t,326.407500),0.200000,if(lt(t,327.907500),t*0.533333-173.884000,if(lt(t,342.520000),1.000000,if(lt(t,344.020000),183.677333-t*0.533333,if(lt(t,356.185000),0.200000,if(lt(t,357.685000),t*0.533333-189.765333,if(lt(t,362.285000),1.000000,if(lt(t,363.785000),194.218667-t*0.533333,if(lt(t,375.165000),0.200000,if(lt(t,376.665000),t*0.533333-199.888000,if(lt(t,398.730000),1.000000,if(lt(t,400.230000),213.656000-t*0.533333,if(lt(t,415.480000),0.200000,if(lt(t,416.980000),t*0.533333-221.389333,if(lt(t,424.930000),1.000000,if(lt(t,426.430000),227.629333-t*0.533333,if(lt(t,435.165000),0.200000,if(lt(t,436.665000),t*0.533333-231.888000,if(lt(t,460.680000),1.000000,if(lt(t,462.180000),246.696000-t*0.533333,if(lt(t,468.380000),0.200000,if(lt(t,469.880000),t*0.533333-249.602667,if(lt(t,480.265000),1.000000,if(lt(t,481.765000),257.141333-t*0.533333,if(lt(t,505.625000),0.200000,if(lt(t,507.125000),t*0.533333-269.466667,if(lt(t,520.680000),1.000000,if(lt(t,522.180000),278.696000-t*0.533333,if(lt(t,534.911250),0.200000,if(lt(t,536.411250),t*0.533333-285.086000,if(lt(t,543.953750),1.000000,if(lt(t,545.453750),291.108667-t*0.533333,if(lt(t,567.088750),0.200000,if(lt(t,568.588750),t*0.533333-302.247333,if(lt(t,575.466250),1.000000,if(lt(t,576.966250),307.915333-t*0.533333,if(lt(t,585.165000),0.200000,if(lt(t,586.665000),t*0.533333-311.888000,if(lt(t,702.800000),1.000000,if(lt(t,704.300000),375.826667-t*0.533333,if(lt(t,708.380000),0.200000,if(lt(t,709.880000),t*0.533333-377.602667,if(lt(t,720.265000),1.000000,if(lt(t,721.765000),385.141333-t*0.533333,if(lt(t,736.180000),0.200000,if(lt(t,737.680000),t*0.533333-392.429333,if(lt(t,778.787500),1.000000,if(lt(t,780.287500),416.353333-t*0.533333,if(lt(t,795.165000),0.200000,if(lt(t,796.665000),t*0.533333-423.888000,if(lt(t,823.190000),1.000000,if(lt(t,824.690000),440.034667-t*0.533333,if(lt(t,840.003750),0.200000,if(lt(t,841.503750),t*0.533333-447.802000,if(lt(t,901.952500),1.000000,if(lt(t,903.452500),482.041333-t*0.533333,if(lt(t,907.227500),0.200000,if(lt(t,908.727500),t*0.533333-483.654667,if(lt(t,933.980000),1.000000,if(lt(t,935.480000),499.122667-t*0.533333,if(lt(t,948.380000),0.200000,if(lt(t,949.880000),t*0.533333-505.602667,if(lt(t,960.265000),1.000000,if(lt(t,961.765000),513.141333-t*0.533333,if(lt(t,965.400000),0.200000,if(lt(t,966.900000),t*0.533333-514.680000,if(lt(t,980.090000),1.000000,if(lt(t,981.590000),523.714667-t*0.533333,if(lt(t,988.780000),0.200000,if(lt(t,990.280000),t*0.533333-527.149333,if(lt(t,1053.718750),1.000000,if(lt(t,1055.218750),562.983333-t*0.533333,if(lt(t,1059.013750),0.200000,if(lt(t,1060.513750),t*0.533333-564.607333,if(lt(t,1093.170000),1.000000,if(lt(t,1094.670000),584.024000-t*0.533333,if(lt(t,1108.431250),0.200000,if(lt(t,1109.931250),t*0.533333-590.963333,if(lt(t,1181.940000),1.000000,if(lt(t,1183.440000),631.368000-t*0.533333,if(lt(t,1188.380000),0.200000,if(lt(t,1189.880000),t*0.533333-633.602667,if(lt(t,1200.265000),1.000000,if(lt(t,1201.765000),641.141333-t*0.533333,if(lt(t,1219.775000),0.200000,if(lt(t,1221.275000),t*0.533333-650.346667,if(lt(t,1300.890000),1.000000,if(lt(t,1302.390000),694.808000-t*0.533333,if(lt(t,1307.170000),0.200000,if(lt(t,1308.670000),t*0.533333-696.957333,if(lt(t,1353.980000),1.000000,if(lt(t,1355.480000),723.122667-t*0.533333,if(lt(t,1370.510000),0.200000,if(lt(t,1372.010000),t*0.533333-730.738667,if(lt(t,1395.265000),1.000000,if(lt(t,1396.765000),745.141333-t*0.533333,if(lt(t,1400.630000),0.200000,if(lt(t,1402.130000),t*0.533333-746.802667,1.000000)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))':eval=frame

[Parsed_volume_41 @ 0x47bfd40] [Eval @ 0x7fff1f9d25f0] Missing ')' or too many args in 'if(lt(t,948.380000),0.200000,if(lt(t,949.880000),t*0.533333-505.602667,if(lt(t,960.265000),1.000000,if(lt(t,961.765000),513.141333-t*0.533333,if(lt(t,965.400000),0.200000,if(lt(t,966.900000),t*0.533333-514.680000,if(lt(t,980.090000),1.000000,if(lt(t,981.590000),523.714667-t*0.533333,if(lt(t,988.780000),0.200000,if(lt(t,990.280000),t*0.533333-527.149333,if(lt(t,1053.718750),1.000000,if(lt(t,1055.218750),562.983333-t*0.533333,if(lt(t,1059.013750),0.200000,if(lt(t,1060.513750),t*0.533333-564.607333,if(lt(t,1093.170000),1.000000,if(lt(t,1094.670000),584.024000-t*0.533333,if(lt(t,1108.431250),0.200000,if(lt(t,1109.931250),t*0.533333-590.963333,if(lt(t,1181.940000),1.000000,if(lt(t,1183.440000),631.368000-t*0.533333,if(lt(t,1188.380000),0.200000,if(lt(t,1189.880000),t*0.533333-633.602667,if(lt(t,1200.265000),1.000000,if(lt(t,1201.765000),641.141333-t*0.533333,if(lt(t,1219.775000),0.200000,if(lt(t,1221.275000),t*0.533333-650.346667,if(lt(t,1300.890000),1.000000,if(lt(t,1302.390000),694.808000-t*0.533333,if(lt(t,1307.170000),0.200000,if(lt(t,1308.670000),t*0.533333-696.957333,if(lt(t,1353.980000),1.000000,if(lt(t,1355.480000),723.122667-t*0.533333,if(lt(t,1370.510000),0.200000,if(lt(t,1372.010000),t*0.533333-730.738667,if(lt(t,1395.265000),1.000000,if(lt(t,1396.765000),745.141333-t*0.533333,if(lt(t,1400.630000),0.200000,if(lt(t,1402.130000),t*0.533333-746.802667,1.000000)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))'
...
...
[Parsed_volume_41 @ 0x47bfd40] [Eval @ 0x7fff1f9d25f0] Missing ')' or too many args in 'if(lt(t,0.500000),0.466667-t*0.533333,if(lt(t,37.165000),0.200000,if(lt(t,38.665000),t*0.533333-19.621333,if(lt(t,45.265000),1.000000,if(lt(t,46.765000),25.141333-t*0.533333,if(lt(t,64.200000),0.200000,if(lt(t,65.700000),t*0.533333-34.040000,if(lt(t,75.265000),1.000000,if(lt(t,76.765000),41.141333-t*0.533333,if(lt(t,80.580000),0.200000,if(lt(t,82.080000),t*0.533333-42.776000,if(lt(t,105.265000),1.000000,if(lt(t,106.765000),57.141333-t*0.533333,if(lt(t,117.015000),0.200000,if(lt(t,118.515000),t*0.533333-62.208000,if(lt(t,165.265000),1.000000,if(lt(t,166.765000),89.141333-t*0.533333,if(lt(t,173.600000),0.200000,if(lt(t,175.100000),t*0.533333-92.386667,if(lt(t,180.265000),1.000000,if(lt(t,181.765000),97.141333-t*0.533333,if(lt(t,195.160000),0.200000,if(lt(t,196.660000),t*0.533333-103.885333,if(lt(t,258.588750),1.000000,if(lt(t,260.088750),138.914000-t*0.533333,if(lt(t,263.693750),0.200000,if(lt(t,265.193750),t*0.533333-140.436667,if(lt(t,270.441250),1.000000,if(lt(t,271.941250),145.235333-t*0.533333,if(lt(t,296.705000),0.200000,if(lt(t,298.205000),t*0.533333-158.042667,if(lt(t,305.515000),1.000000,if(lt(t,307.015000),163.941333-t*0.533333,if(lt(t,310.810000),0.200000,if(lt(t,312.310000),t*0.533333-165.565333,if(lt(t,320.602500),1.000000,if(lt(t,322.102500),171.988000-t*0.533333,if(lt(t,326.407500),0.200000,if(lt(t,327.907500),t*0.533333-173.884000,if(lt(t,342.520000),1.000000,if(lt(t,344.020000),183.677333-t*0.533333,if(lt(t,356.185000),0.200000,if(lt(t,357.685000),t*0.533333-189.765333,if(lt(t,362.285000),1.000000,if(lt(t,363.785000),194.218667-t*0.533333,if(lt(t,375.165000),0.200000,if(lt(t,376.665000),t*0.533333-199.888000,if(lt(t,398.730000),1.000000,if(lt(t,400.230000),213.656000-t*0.533333,if(lt(t,415.480000),0.200000,if(lt(t,416.980000),t*0.533333-221.389333,if(lt(t,424.930000),1.000000,if(lt(t,426.430000),227.629333-t*0.533333,if(lt(t,435.165000),0.200000,if(lt(t,436.665000),t*0.533333-231.888000,if(lt(t,460.680000),1.000000,if(lt(t,462.180000),246.696000-t*0.533333,if(lt(t,468.380000),0.200000,if(lt(t,469.880000),t*0.533333-249.602667,if(lt(t,480.265000),1.000000,if(lt(t,481.765000),257.141333-t*0.533333,if(lt(t,505.625000),0.200000,if(lt(t,507.125000),t*0.533333-269.466667,if(lt(t,520.680000),1.000000,if(lt(t,522.180000),278.696000-t*0.533333,if(lt(t,534.911250),0.200000,if(lt(t,536.411250),t*0.533333-285.086000,if(lt(t,543.953750),1.000000,if(lt(t,545.453750),291.108667-t*0.533333,if(lt(t,567.088750),0.200000,if(lt(t,568.588750),t*0.533333-302.247333,if(lt(t,575.466250),1.000000,if(lt(t,576.966250),307.915333-t*0.533333,if(lt(t,585.165000),0.200000,if(lt(t,586.665000),t*0.533333-311.888000,if(lt(t,702.800000),1.000000,if(lt(t,704.300000),375.826667-t*0.533333,if(lt(t,708.380000),0.200000,if(lt(t,709.880000),t*0.533333-377.602667,if(lt(t,720.265000),1.000000,if(lt(t,721.765000),385.141333-t*0.533333,if(lt(t,736.180000),0.200000,if(lt(t,737.680000),t*0.533333-392.429333,if(lt(t,778.787500),1.000000,if(lt(t,780.287500),416.353333-t*0.533333,if(lt(t,795.165000),0.200000,if(lt(t,796.665000),t*0.533333-423.888000,if(lt(t,823.190000),1.000000,if(lt(t,824.690000),440.034667-t*0.533333,if(lt(t,840.003750),0.200000,if(lt(t,841.503750),t*0.533333-447.802000,if(lt(t,901.952500),1.000000,if(lt(t,903.452500),482.041333-t*0.533333,if(lt(t,907.227500),0.200000,if(lt(t,908.727500),t*0.533333-483.654667,if(lt(t,933.980000),1.000000,if(lt(t,935.480000),499.122667-t*0.533333,if(lt(t,948.380000),0.200000,if(lt(t,949.880000),t*0.533333-505.602667,if(lt(t,960.265000),1.000000,if(lt(t,961.765000),513.141333-t*0.533333,if(lt(t,965.400000),0.200000,if(lt(t,966.900000),t*0.533333-514.680000,if(lt(t,980.090000),1.000000,if(lt(t,981.590000),523.714667-t*0.533333,if(lt(t,988.780000),0.200000,if(lt(t,990.280000),t*0.533333-527.149333,if(lt(t,1053.718750),1.000000,if(lt(t,1055.218750),562.983333-t*0.533333,if(lt(t,1059.013750),0.200000,if(lt(t,1060.513750),t*0.533333-564.607333,if(lt(t,1093.170000),1.000000,if(lt(t,1094.670000),584.024000-t*0.533333,if(lt(t,1108.431250),0.200000,if(lt(t,1109.931250),t*0.533333-590.963333,if(lt(t,1181.940000),1.000000,if(lt(t,1183.440000),631.368000-t*0.533333,if(lt(t,1188.380000),0.200000,if(lt(t,1189.880000),t*0.533333-633.602667,if(lt(t,1200.265000),1.000000,if(lt(t,1201.765000),641.141333-t*0.533333,if(lt(t,1219.775000),0.200000,if(lt(t,1221.275000),t*0.533333-650.346667,if(lt(t,1300.890000),1.000000,if(lt(t,1302.390000),694.808000-t*0.533333,if(lt(t,1307.170000),0.200000,if(lt(t,1308.670000),t*0.533333-696.957333,if(lt(t,1353.980000),1.000000,if(lt(t,1355.480000),723.122667-t*0.533333,if(lt(t,1370.510000),0.200000,if(lt(t,1372.010000),t*0.533333-730.738667,if(lt(t,1395.265000),1.000000,if(lt(t,1396.765000),745.141333-t*0.533333,if(lt(t,1400.630000),0.200000,if(lt(t,1402.130000),t*0.533333-746.802667,1.000000)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))'
[Parsed_volume_41 @ 0x47bfd40] Error when evaluating the volume expression 'if(lt(t,0.500000),0.466667-t*0.533333,if(lt(t,37.165000),0.200000,if(lt(t,38.665000),t*0.533333-19.621333,if(lt(t,45.265000),1.000000,if(lt(t,46.765000),25.141333-t*0.533333,if(lt(t,64.200000),0.200000,if(lt(t,65.700000),t*0.533333-34.040000,if(lt(t,75.265000),1.000000,if(lt(t,76.765000),41.141333-t*0.533333,if(lt(t,80.580000),0.200000,if(lt(t,82.080000),t*0.533333-42.776000,if(lt(t,105.265000),1.000000,if(lt(t,106.765000),57.141333-t*0.533333,if(lt(t,117.015000),0.200000,if(lt(t,118.515000),t*0.533333-62.208000,if(lt(t,165.265000),1.000000,if(lt(t,166.765000),89.141333-t*0.533333,if(lt(t,173.600000),0.200000,if(lt(t,175.100000),t*0.533333-92.386667,if(lt(t,180.265000),1.000000,if(lt(t,181.765000),97.141333-t*0.533333,if(lt(t,195.160000),0.200000,if(lt(t,196.660000),t*0.533333-103.885333,if(lt(t,258.588750),1.000000,if(lt(t,260.088750),138.914000-t*0.533333,if(lt(t,263.693750),0.200000,if(lt(t,265.193750),t*0.533333-140.436667,if(lt(t,270.441250),1.000000,if(lt(t,271.941250),145.235333-t*0.533333,if(lt(t,296.705000),0.200000,if(lt(t,298.205000),t*0.533333-158.042667,if(lt(t,305.515000),1.000000,if(lt(t,307.015000),163.941333-t*0.533333,if(lt(t,310.810000),0.200000,if(lt(t,312.310000),t*0.533333-165.565333,if(lt(t,320.602500),1.000000,if(lt(t,322.102500),171.988000-t*0.533333,if(lt(t,326.407500),0.200000,if(lt(t,327.907500),t*0.533333-173.884000,if(lt(t,342.520000),1.000000,if(lt(t,344.020000),183.677333-t*0.533333,if(lt(t,356.185000),0.200000,if(lt(t,357.685000),t*0.533333-189.765333,if(lt(t,362.285000),1.000000,if(lt(t,363.785000),194.218667-t*0.533333,if(lt(t,375.165000),0.200000,if(lt(t,376.665000),t*0.533333-199.888000,if(lt(t,398.730000),1.000000,if(lt(t,400.230000),213.656000-t*0.533333,if(lt(t,415.480000),0.200000,if(lt(t,416.980000),t*0.533333-221.389333,if(lt(t,424.930000),1.000000,if(lt(t,426.430000),227.629333-t*0.533333,if(lt(t,435.165000),0.200000,if(lt(t,436.665000),t*0.533333-231.888000,if(lt(t,460.680000),1.000000,if(lt(t,462.180000),246.696000-t*0.533333,if(lt(t,468.380000),0.200000,if(lt(t,469.880000),t*0.533333-249.602667,if(lt(t,480.265000),1.000000,if(lt(t,481.765000),257.141333-t*0.533333,if(lt(t,505.625000),0.200000,if(lt(t,507.125000),t*0.533333-269.466667,if(lt(t,520.680000),1.000000,if(lt(t,522.180000),278.696000-t*0.533333,if(lt(t,534.911250),0.200000,if(lt(t,536.411250),t*0.533333-285.086000,if(lt(t,543.953750),1.000000,if(lt(t,545.453750),291.108667-t*0.533333,if(lt(t,567.088750),0.200000,if(lt(t,568.588750),t*0.533333-302.247333,if(lt(t,575.466250),1.000000,if(lt(t,576.966250),307.915333-t*0.533333,if(lt(t,585.165000),0.200000,if(lt(t,586.665000),t*0.533333-311.888000,if(lt(t,702.800000),1.000000,if(lt(t,704.300000),375.826667-t*0.533333,if(lt(t,708.380000),0.200000,if(lt(t,709.880000),t*0.533333-377.602667,if(lt(t,720.265000),1.000000,if(lt(t,721.765000),385.141333-t*0.533333,if(lt(t,736.180000),0.200000,if(lt(t,737.680000),t*0.533333-392.429333,if(lt(t,778.787500),1.000000,if(lt(t,780.287500),416.353333-t*0.533333,if(lt(t,795.165000),0.200000,if(lt(t,796.665000),t*0.533333-423.888000,if(lt(t,823.190000),1.000000,if(lt(t,824.690000),440.034667-t*0.533333,if(lt(t,840.003750),0.200000,if(lt(t,841.503750),t*0.533333-447.802000,if(lt(t,901.952500),1.000000,if(lt(t,903.452500),482.041333-t*0.533333,if(lt(t,907.227500),0.200000,if(lt(t,908.727500),t*0.533333-483.654667,if(lt(t,933.980000),1.000000,if(lt(t,935.480000),499.122667-t*0.533333,if(lt(t,948.380000),0.200000,if(lt(t,949.880000),t*0.533333-505.602667,if(lt(t,960.265000),1.000000,if(lt(t,961.765000),513.141333-t*0.533333,if(lt(t,965.400000),0.200000,if(lt(t,966.900000),t*0.533333-514.680000,if(lt(t,980.090000),1.000000,if(lt(t,981.590000),523.714667-t*0.533333,if(lt(t,988.780000),0.200000,if(lt(t,990.280000),t*0.533333-527.149333,if(lt(t,1053.718750),1.000000,if(lt(t,1055.218750),562.983333-t*0.533333,if(lt(t,1059.013750),0.200000,if(lt(t,1060.513750),t*0.533333-564.607333,if(lt(t,1093.170000),1.000000,if(lt(t,1094.670000),584.024000-t*0.533333,if(lt(t,1108.431250),0.200000,if(lt(t,1109.931250),t*0.533333-590.963333,if(lt(t,1181.940000),1.000000,if(lt(t,1183.440000),631.368000-t*0.533333,if(lt(t,1188.380000),0.200000,if(lt(t,1189.880000),t*0.533333-633.602667,if(lt(t,1200.265000),1.000000,if(lt(t,1201.765000),641.141333-t*0.533333,if(lt(t,1219.775000),0.200000,if(lt(t,1221.275000),t*0.533333-650.346667,if(lt(t,1300.890000),1.000000,if(lt(t,1302.390000),694.808000-t*0.533333,if(lt(t,1307.170000),0.200000,if(lt(t,1308.670000),t*0.533333-696.957333,if(lt(t,1353.980000),1.000000,if(lt(t,1355.480000),723.122667-t*0.533333,if(lt(t,1370.510000),0.200000,if(lt(t,1372.010000),t*0.533333-730.738667,if(lt(t,1395.265000),1.000000,if(lt(t,1396.765000),745.141333-t*0.533333,if(lt(t,1400.630000),0.200000,if(lt(t,1402.130000),t*0.533333-746.802667,1.000000)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))'
[AVFilterGraph @ 0x46c4300] Error initializing filter 'volume' with args 'if(lt(t,0.500000),0.466667-t*0.533333,if(lt(t,37.165000),0.200000,if(lt(t,38.665000),t*0.533333-19.621333,if(lt(t,45.265000),1.000000,if(lt(t,46.765000),25.141333-t*0.533333,if(lt(t,64.200000),0.200000,if(lt(t,65.700000),t*0.533333-34.040000,if(lt(t,75.265000),1.000000,if(lt(t,76.765000),41.141333-t*0.533333,if(lt(t,80.580000),0.200000,if(lt(t,82.080000),t*0.533333-42.776000,if(lt(t,105.265000),1.000000,if(lt(t,106.765000),57.141333-t*0.533333,if(lt(t,117.015000),0.200000,if(lt(t,118.515000),t*0.533333-62.208000,if(lt(t,165.265000),1.000000,if(lt(t,166.765000),89.141333-t*0.533333,if(lt(t,173.600000),0.200000,if(lt(t,175.100000),t*0.533333-92.386667,if(lt(t,180.265000),1.000000,if(lt(t,181.765000),97.141333-t*0.533333,if(lt(t,195.160000),0.200000,if(lt(t,196.660000),t*0.533333-103.885333,if(lt(t,258.588750),1.000000,if(lt(t,260.088750),138.914000-t*0.533333,if(lt(t,263.693750),0.200000,if(lt(t,265.193750),t*0.533333-140.436667,if(lt(t,270.441250),1.000000,if(lt(t,271.941250),145.235333-t*0.533333,if(lt(t,296.705000),0.200000,if(lt(t,298.205000),t*0.533333-158.042667,if(lt(t,305.515000),1.000000,if(lt(t,307.015000),163.941333-t*0.533333,if(lt(t,310.810000),0.200000,if(lt(t,312.310000),t*0.533333-165.565333,if(lt(t,320.602500),1.000000,if(lt(t,322.102500),171.988000-t*0.533333,if(lt(t,326.407500),0.200000,if(lt(t,327.907500),t*0.533333-173.884000,if(lt(t,342.520000),1.000000,if(lt(t,344.020000),183.677333-t*0.533333,if(lt(t,356.185000),0.200000,if(lt(t,357.685000),t*0.533333-189.765333,if(lt(t,362.285000),1.000000,if(lt(t,363.785000),194.218667-t*0.533333,if(lt(t,375.165000),0.200000,if(lt(t,376.665000),t*0.533333-199.888000,if(lt(t,398.730000),1.000000,if(lt(t,400.230000),213.656000-t*0.533333,if(lt(t,415.480000),0.200000,if(lt(t,416.980000),t*0.533333-221.389333,if(lt(t,424.930000),1.000000,if(lt(t,426.430000),227.629333-t*0.533333,if(lt(t,435.165000),0.200000,if(lt(t,436.665000),t*0.533333-231.888000,if(lt(t,460.680000),1.000000,if(lt(t,462.180000),246.696000-t*0.533333,if(lt(t,468.380000),0.200000,if(lt(t,469.880000),t*0.533333-249.602667,if(lt(t,480.265000),1.000000,if(lt(t,481.765000),257.141333-t*0.533333,if(lt(t,505.625000),0.200000,if(lt(t,507.125000),t*0.533333-269.466667,if(lt(t,520.680000),1.000000,if(lt(t,522.180000),278.696000-t*0.533333,if(lt(t,534.911250),0.200000,if(lt(t,536.411250),t*0.533333-285.086000,if(lt(t,543.953750),1.000000,if(lt(t,545.453750),291.108667-t*0.533333,if(lt(t,567.088750),0.200000,if(lt(t,568.588750),t*0.533333-302.247333,if(lt(t,575.466250),1.000000,if(lt(t,576.966250),307.915333-t*0.533333,if(lt(t,585.165000),0.200000,if(lt(t,586.665000),t*0.533333-311.888000,if(lt(t,702.800000),1.000000,if(lt(t,704.300000),375.826667-t*0.533333,if(lt(t,708.380000),0.200000,if(lt(t,709.880000),t*0.533333-377.602667,if(lt(t,720.265000),1.000000,if(lt(t,721.765000),385.141333-t*0.533333,if(lt(t,736.180000),0.200000,if(lt(t,737.680000),t*0.533333-392.429333,if(lt(t,778.787500),1.000000,if(lt(t,780.287500),416.353333-t*0.533333,if(lt(t,795.165000),0.200000,if(lt(t,796.665000),t*0.533333-423.888000,if(lt(t,823.190000),1.000000,if(lt(t,824.690000),440.034667-t*0.533333,if(lt(t,840.003750),0.200000,if(lt(t,841.503750),t*0.533333-447.802000,if(lt(t,901.952500),1.000000,if(lt(t,903.452500),482.041333-t*0.533333,if(lt(t,907.227500),0.200000,if(lt(t,908.727500),t*0.533333-483.654667,if(lt(t,933.980000),1.000000,if(lt(t,935.480000),499.122667-t*0.533333,if(lt(t,948.380000),0.200000,if(lt(t,949.880000),t*0.533333-505.602667,if(lt(t,960.265000),1.000000,if(lt(t,961.765000),513.141333-t*0.533333,if(lt(t,965.400000),0.200000,if(lt(t,966.900000),t*0.533333-514.680000,if(lt(t,980.090000),1.000000,if(lt(t,981.590000),523.714667-t*0.533333,if(lt(t,988.780000),0.200000,if(lt(t,990.280000),t*0.533333-527.149333,if(lt(t,1053.718750),1.000000,if(lt(t,1055.218750),562.983333-t*0.533333,if(lt(t,1059.013750),0.200000,if(lt(t,1060.513750),t*0.533333-564.607333,if(lt(t,1093.170000),1.000000,if(lt(t,1094.670000),584.024000-t*0.533333,if(lt(t,1108.431250),0.200000,if(lt(t,1109.931250),t*0.533333-590.963333,if(lt(t,1181.940000),1.000000,if(lt(t,1183.440000),631.368000-t*0.533333,if(lt(t,1188.380000),0.200000,if(lt(t,1189.880000),t*0.533333-633.602667,if(lt(t,1200.265000),1.000000,if(lt(t,1201.765000),641.141333-t*0.533333,if(lt(t,1219.775000),0.200000,if(lt(t,1221.275000),t*0.533333-650.346667,if(lt(t,1300.890000),1.000000,if(lt(t,1302.390000),694.808000-t*0.533333,if(lt(t,1307.170000),0.200000,if(lt(t,1308.670000),t*0.533333-696.957333,if(lt(t,1353.980000),1.000000,if(lt(t,1355.480000),723.122667-t*0.533333,if(lt(t,1370.510000),0.200000,if(lt(t,1372.010000),t*0.533333-730.738667,if(lt(t,1395.265000),1.000000,if(lt(t,1396.765000),745.141333-t*0.533333,if(lt(t,1400.630000),0.200000,if(lt(t,1402.130000),t*0.533333-746.802667,1.000000))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))):eval=frame'

Questions:

How can I determine what the limit on command expression size is, and can this limit be raised by some ffmpeg configuration?
Is there a better way of adjusting volume in an audio file according to an arbitrarily long message list of fade ins & fade outs?

Thanks for reading!

Solution

There's a depth limit of 100. Your last subexpression is nested 135 levels.

Refactor your expression to the form

between(t,START1,END1)*(VOL_EXPR1)+between(t,START2,END2)*(VOL_EXPR2)+...

The shell may enforce a command character limit. Use -filter_complex_script to read from a text file.