[FFmpeg-user] Optimization

[Paul B Mahol]

Hi,

On 11/1/18, Marcus Lim <drakeskywing at gmail.com> wrote:
> Hey all,
> New to the list and trying to get my head around ffmpeg a bit still.
> So I am using ffmpeg to create slideshows out of individual images, with an
> audio backing track (usually mp3), and then encoding as MP4 (video is h264
> and audio is acc), but for some reason the process is taking up to 1.4Gb of
> memory which is blowing me away.
> Now I am using a complex filter to achieve this, with multiple inputs, and
> example of my command is below:
>
> ffmpeg \
> -loop 1 -t 4 -i
> test/ed141148-9b79-494b-a26d-f5c84535eeaf8912937006552540487.tmp \
> -loop 1 -t 4 -i
> test/ed141148-9b79-494b-a26d-f5c84535eeaf5351513282402727883.tmp \
> -loop 1 -t 4 -i
> test/ed141148-9b79-494b-a26d-f5c84535eeaf9204204500598689609.tmp \
> -loop 1 -t 4 -i
> test/ed141148-9b79-494b-a26d-f5c84535eeaf1241593939921003895.tmp \
> -loop 1 -t 4 -i
> test/ed141148-9b79-494b-a26d-f5c84535eeaf6231405065182432206.tmp \
> -loop 1 -t 4 -i
> test/ed141148-9b79-494b-a26d-f5c84535eeaf4783563520441940155.tmp \
> -loop 1 -t 4 -i
> test/ed141148-9b79-494b-a26d-f5c84535eeaf823726872837129805.tmp \
> -loop 1 -t 4 -i
> test/ed141148-9b79-494b-a26d-f5c84535eeaf4148893068919936811.tmp \
> -loop 1 -t 4 -i
> test/ed141148-9b79-494b-a26d-f5c84535eeaf6815991692415841819.tmp \
> -loop 1 -t 4 -i
> test/ed141148-9b79-494b-a26d-f5c84535eeaf553287365250808111.tmp \
> -loop 1 -t 4 -i
> test/ed141148-9b79-494b-a26d-f5c84535eeaf6763129487770212040.tmp \
> -loop 1 -t 4 -i
> test/ed141148-9b79-494b-a26d-f5c84535eeaf4160943340255327277.tmp \
> -loop 1 -t 4 -i
> test/ed141148-9b79-494b-a26d-f5c84535eeaf8834606975865492644.tmp \
> -loop 1 -t 4 -i
> test/ed141148-9b79-494b-a26d-f5c84535eeaf9160476045329137307.tmp \
> -loop 1 -t 4 -i
> test/ed141148-9b79-494b-a26d-f5c84535eeaf8917976550433767102.tmp \
> -stream_loop -1 -t 60 -i
> test/ed141148-9b79-494b-a26d-f5c84535eeaf6379741644027890621.tmp  \
> -filter_complex \
> "[0:v]scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v0];\
> [1:v]scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v1];\
> [2:v]scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v2];\
> [3:v]scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v3];\
> [4:v]scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v4];\
> [5:v]scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v5];\
> [6:v]scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v6];\
> [7:v]scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v7];\
> [8:v]scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v8];\
> [9:v]scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v9];\
> [10:v]scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v10];\
> [11:v]scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v11];\
> [12:v]scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v12];\
> [13:v]scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v13];\
> [14:v]scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2,setsar=1[v14];\
> [v0][v1][v2][v3][v4][v5][v6][v7][v8][v9][v10][v11][v12][v13][v14]concat=n=15:v=1:a=0,format=yuv420p[v]"
> -map "[v]" -map 15:a test/fcd2b1a9-f3c8-4cdc-8355-51c08b088ee3.mp4
>
> Each loop is on a 4Mb Jpeg, and the stream_loop was the only way I could
> figure out to get the audio track to loop in the background, which is about
> 4Mb as well.
>
> I'm kinda stumped as to why this would be with my limited understanding of
> ffmpeg, I have some theories surrounding the -loop filling memory with
> copies of the img in a lossless format but any help would be most welcome.

Full uncut ffmpeg ouput missing.

I bet you are using too old version, which have bug regarding using
too much memory.