FFMPEG command runs in terminal but not by subprocess

Question

I am trying to run a bash command using the subprocess module from within python 3.10.

The bash command is:

ffmpeg -framerate 1 -pattern_type glob -i '*.png' -c:v libx264 -pix_fmt yuv420p -vf "crop=trunc(iw/2)*2:trunc(ih/2)*2" out.mp4

In terminal the command runs fine. Here is the output:

ffmpeg version 4.2.7-0ubuntu0.1 Copyright (c) 2000-2022 the FFmpeg developers
  built with gcc 9 (Ubuntu 9.4.0-1ubuntu1~20.04.1)
  configuration: --prefix=/usr --extra-version=0ubuntu0.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Input #0, image2, from '*.png':
  Duration: 00:16:39.00, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: png, rgba(pc), 895x332 [SAR 3937:3937 DAR 895:332], 1 fps, 1 tbr, 1 tbn, 1 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (png (native) -> h264 (libx264))
Press [q] to stop, [?] for help
[libx264 @ 0x55726ab95d00] using SAR=1/1
[libx264 @ 0x55726ab95d00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2 AVX512
[libx264 @ 0x55726ab95d00] profile High, level 2.2
[libx264 @ 0x55726ab95d00] 264 - core 155 r2917 0a84d98 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=10 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=1 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'out.mp4':
  Metadata:
    encoder         : Lavf58.29.100
    Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 894x332 [SAR 1:1 DAR 447:166], q=-1--1, 1 fps, 16384 tbn, 1 tbc
    Metadata:
      encoder         : Lavc58.54.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
frame=  173 fps=0.0 q=17.0 size=     512kB time=00:01:56.00 bitrate=  36.2kbits/frame=  351 fps=350 q=17.0 size=    1536kB time=00:04:54.00 bitrate=  42.8kbits/frame=  517 fps=343 q=17.0 size=    2560kB time=00:07:40.00 bitrate=  45.6kbits/frame=  725 fps=361 q=17.0 size=    3328kB time=00:11:08.00 bitrate=  40.8kbits/frame=  913 fps=364 q=17.0 size=    4352kB time=00:14:16.00 bitrate=  41.6kbits/frame=  999 fps=361 q=-1.0 Lsize=    4986kB time=00:16:36.00 bitrate=  41.0kbits/s speed= 360x    
video:4974kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.241361%
[libx264 @ 0x55726ab95d00] frame I:4     Avg QP: 6.12  size: 24072
[libx264 @ 0x55726ab95d00] frame P:346   Avg QP:12.94  size:  5708
[libx264 @ 0x55726ab95d00] frame B:649   Avg QP:18.19  size:  4655
[libx264 @ 0x55726ab95d00] consecutive B-frames:  5.8% 16.0% 20.1% 58.1%
[libx264 @ 0x55726ab95d00] mb I  I16..4: 59.1% 10.6% 30.4%
[libx264 @ 0x55726ab95d00] mb P  I16..4:  5.6%  0.6%  2.2%  P16..4: 10.5%  4.3%  2.3%  0.0%  0.0%    skip:74.5%
[libx264 @ 0x55726ab95d00] mb B  I16..4:  2.2%  0.1%  1.7%  B16..8: 16.9%  4.8%  1.6%  direct: 1.1%  skip:71.5%  L0:50.9% L1:45.2% BI: 3.9%
[libx264 @ 0x55726ab95d00] 8x8 transform intra:5.9% inter:10.4%
[libx264 @ 0x55726ab95d00] coded y,uvDC,uvAC intra: 20.1% 18.3% 17.3% inter: 4.7% 4.7% 4.6%
[libx264 @ 0x55726ab95d00] i16 v,h,dc,p: 66% 33%  1%  0%
[libx264 @ 0x55726ab95d00] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 18%  8% 73%  0%  0%  0%  0%  0%  0%
[libx264 @ 0x55726ab95d00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 23% 31% 31%  2%  3%  2%  4%  2%  3%
[libx264 @ 0x55726ab95d00] i8c dc,h,v,p: 73% 23%  3%  0%
[libx264 @ 0x55726ab95d00] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 0x55726ab95d00] ref P L0: 57.2%  1.5% 24.3% 17.0%
[libx264 @ 0x55726ab95d00] ref B L0: 69.6% 24.8%  5.6%
[libx264 @ 0x55726ab95d00] ref B L1: 92.4%  7.6%
[libx264 @ 0x55726ab95d00] kb/s:40.78

In my python script I tried the following solutions:

video_cmd = """ffmpeg -framerate 1 -pattern_type glob -i '*.png' -c:v libx264 -pix_fmt yuv420p -vf "crop=trunc(iw/2)*2:trunc(ih/2)*2" out.mp4"""

subprocess.run(shlex.split(video_cmd), shell=False, cwd=path_viz, stderr=subprocess.STDOUT, check=True, text=False)

subprocess.run(video_cmd, shell=True, cwd=path_viz, stderr=subprocess.STDOUT, check=True, text=False)

as well as the solution proposed for this similar question

subprocess.Popen(video_cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)

None of them worked. Apparently, the right command is run (output of the check_out function):

Command 'ffmpeg -y -framerate 1 -pattern_type glob -i '*.png' -c:v libx264 -pix_fmt yuv420p -vf "crop=trunc(iw/2)*2:trunc(ih/2)*2" out.mp4' returned non-zero exit status 1.

the first part of the job (up to Stream mapping:) is done also correctly :

fmpeg version 4.3 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 7.3.0 (crosstool-NG 1.23.0.449-a04d0)
  configuration: --prefix=/home/rsghazanfari/anaconda3/envs/_cuda --cc=/opt/conda/conda-bld/ffmpeg_1597178665428/_build_env/bin/x86_64-conda_cos6-linux-gnu-cc --disable-doc --disable-openssl --enable-avresample --enable-gnutls --enable-hardcoded-tables --enable-libfreetype --enable-libopenh264 --enable-pic --enable-pthreads --enable-shared --disable-static --enable-version3 --enable-zlib --enable-libmp3lame
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
Input #0, image2, from '*.png':
  Duration: 00:16:39.00, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: png, rgba(pc), 895x332 [SAR 3937:3937 DAR 895:332], 1 fps, 1 tbr, 1 tbn, 1 tbc

but it then pops up the following error:

Unknown encoder 'libx264'
Traceback (most recent call last):
  File "/home/rsgh/anaconda3/envs/_cuda/lib/python3.10/code.py", line 90, in runcode
    exec(code, self.locals)
  File "<input>", line 1, in <module>
  File "/home/rsgh/anaconda3/envs/_cuda/lib/python3.10/subprocess.py", line 524, in run
    raise CalledProcessError(retcode, process.args,

subprocess.CalledProcessError: Command 'ffmpeg -y -framerate 1 -pattern_type glob -i '*.png' -c:v libx264 -pix_fmt yuv420p -vf "crop=trunc(iw/2)*2:trunc(ih/2)*2" out.mp4' returned non-zero exit status 1.

Any ideas of why this error is produced in python while in terminal it runs fine? Thank you in advance.

PS : ffmpeg -version outputs:

ffmpeg version 4.2.7-0ubuntu0.1 Copyright (c) 2000-2022 the FFmpeg developers
built with gcc 9 (Ubuntu 9.4.0-1ubuntu1~20.04.1)
configuration: --prefix=/usr --extra-version=0ubuntu0.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
libavutil      56. 31.100 / 56. 31.100
libavcodec     58. 54.100 / 58. 54.100
libavformat    58. 29.100 / 58. 29.100
libavdevice    58.  8.100 / 58.  8.100
libavfilter     7. 57.100 /  7. 57.100
libavresample   4.  0.  0 /  4.  0.  0
libswscale      5.  5.100 /  5.  5.100
libswresample   3.  5.100 /  3.  5.100
libpostproc    55.  5.100 / 55.  5.100

ubuntu version:

Distributor ID: Ubuntu
Description:    Ubuntu 20.04.4 LTS
Release:    20.04
Codename:   focal

Answer 1

Error shows problem with Unknown encoder 'libx264'.

But real problem is ...

... command in console shows

ffmpeg version 4.2.7-0ubuntu0.1

but command in python shows

ffmpeg version 4.3

which means you have two versions of ffmpeg
and python uses version which doesn't have encoder 'libx264'

You may have to use /full/path/to/ffmpeg in python to use version 4.2.7.

In console use which ffmpeg to get /full/path/to/ffmpeg

---

OR maybe you have second ffmpeg in folder with your script and you should remove it.