ffmpeg xfade eating too much memory(killed by kernel)

[Richard W]

I am using ffmpeg to concatenate some clips with transitions, but it's using up to 15G memory in my machine and it gets killed by the kernel. there are 15 clips (1080P) and total time around 2.5 minutes.

The exact command I am using is:

/data/ffmpeg-git-20210611-amd64-static/ffmpeg -i cut_result0.mp4 -i cut_result1.mp4 -i cut_result2.mp4 -i cut_result3.mp4 -i cut_result4.mp4 -i cut_result5.mp4 -i cut_result6.mp4 -i cut_result7.mp4 -i cut_result8.mp4 -i cut_result9.mp4 -i cut_result10.mp4 -i cut_result11.mp4 -i cut_result12.mp4 -i cut_result13.mp4 -i cut_result14.mp4 -filter_complex "[0:v][1:v]xfade=transition=fadeblack:duration=1.000:offset=8.960[v01];[v01][2:v]xfade=transition=fadeblack:duration=1.000:offset=16.120[v02];[v02][3:v]xfade=transition=fadeblack:duration=1.000:offset=25.760[v03];[v03][4:v]xfade=transition=fadeblack:duration=1.000:offset=34.000[v04];[v04][5:v]xfade=transition=fadeblack:duration=1.000:offset=46.800[v05];[v05][6:v]xfade=transition=fadeblack:duration=1.000:offset=62.440[v06];[v06][7:v]xfade=transition=fadeblack:duration=1.000:offset=70.840[v07];[v07][8:v]xfade=transition=fadeblack:duration=1.000:offset=80.440[v08];[v08][9:v]xfade=transition=fadeblack:duration=1.000:offset=85.360[v09];[v09][10:v]xfade=transition=fadeblack:duration=1.000:offset=114.080[v10];[v10][11:v]xfade=transition=fadeblack:duration=1.000:offset=122.080[v11];[v11][12:v]xfade=transition=fadeblack:duration=1.000:offset=127.400[v12];[v12][13:v]xfade=transition=fadeblack:duration=1.000:offset=132.600[v13];[v13][14:v]xfade=transition=fadeblack:duration=1.000:offset=137.680,format=yuv420p[video];[0:a][1:a]acrossfade=d=1.000:c1=tri:c2=tri[a01];[a01][2:a]acrossfade=d=1.000:c1=tri:c2=tri[a02];[a02][3:a]acrossfade=d=1.000:c1=tri:c2=tri[a03];[a03][4:a]acrossfade=d=1.000:c1=tri:c2=tri[a04];[a04][5:a]acrossfade=d=1.000:c1=tri:c2=tri[a05];[a05][6:a]acrossfade=d=1.000:c1=tri:c2=tri[a06];[a06][7:a]acrossfade=d=1.000:c1=tri:c2=tri[a07];[a07][8:a]acrossfade=d=1.000:c1=tri:c2=tri[a08];[a08][9:a]acrossfade=d=1.000:c1=tri:c2=tri[a09];[a09][10:a]acrossfade=d=1.000:c1=tri:c2=tri[a10];[a10][11:a]acrossfade=d=1.000:c1=tri:c2=tri[a11];[a11][12:a]acrossfade=d=1.000:c1=tri:c2=tri[a12];[a12][13:a]acrossfade=d=1.000:c1=tri:c2=tri[a13];[a13][14:a]acrossfade=d=1.000:c1=tri:c2=tri[audio]" -map [video] -map [audio] -movflags +faststart my_output.mp4

The full log at ​https://pastebin.com/AszkJh6E
Please note the full log is a successful one which I ran on a more powerful machine with 100G+ memory.
The original samples are uploaded to office one drive: ​https://dutaotbsteduau-my.sharepoint.com/:f:/g/personal/i_edu365_site/EoeBxKbg0xBIv2-Ky54dxdEBgw8wUY6ZgEsp2dCNk93LzA?e=tbHyXe

[Carl Eugen Hoyos]

Why do you think that there is a bug that can be fixed in FFmpeg?

[Richard W]

Replying to Carl Eugen Hoyos:

Why do you think that there is a bug that can be fixed in FFmpeg?

I am not sure if it's a bug, just maybe. When I use only xfades or acrossfades in my command, the memory usage looks good, but with both it keeps consuming memory.

[Elon Musk]

That can usually happen when A/V sync drifts so much that it need to keep everything in memory. On more powerful machine you can use single graphmonitor filter to show you filter stats during filtering.
Feel free to report here if it reports red numbers (cache filling too much).

[Elon Musk]

File are gone.

[Elon Musk]

With latest git version, memory usage of xfade/acrossfade should be significantly lower.