FFMPEG not working from Python subprocess.Popen but works from command line

I'm trying to run a FFMPEG script from within python 3.5.2. the FFMPEG command runs fine from the command line but fails within the python script.

The function I use to execute the FFMPEG command is

def ffmpeg(args):
    err = None
    command = [
        ffmpegcmd, '-y',
        '-loglevel', loglevel
    ] + args
    print("\n\n\n")
    print(command)
    print("\n\n\n")
    print(" ".join(command))
    ffmpeg = subprocess.Popen(command, stderr=subprocess.PIPE ,stdout=subprocess.PIPE, universal_newlines=True)
    while err == None:
        out, err = ffmpeg.communicate()
        time.sleep(1)
    if err and loglevel=='fatal':
        print(" ".join(command))
        raise Exception(err)
    print(err)

The value for args is:

['-i', '/var/www/temp/film.mp4', '-vf', 'scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:x=(1920-iw)/2:y=(1080-ih)/2:color=black', '/var/www/temp/videoHD.mp4']

such that the resultant command being passed to subprocess.Popen is:

['ffmpeg', '-y', '-loglevel', 'verbose', '-i', '/var/www/temp/film.mp4', '-vf', 'scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:x=(1920-iw)/2:y=(1080-ih)/2:color=black', '/var/www/temp/videoHD.mp4']

The value of loglevel is verbose only for troubleshooting but is intended to run as fatal. There are also some print commands only in place for troubleshooting.

The reason for wanting to increase the resolution is so that it can be combined later with higher resolution videos.

The result when running from within python is:

ffmpeg version 3.3.4-2~16.04.york0 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.4) 20160609
  configuration: --prefix=/usr --extra-version='2~16.04.york0' --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  libavutil      55. 58.100 / 55. 58.100
  libavcodec     57. 89.100 / 57. 89.100
  libavformat    57. 71.100 / 57. 71.100
  libavdevice    57.  6.100 / 57.  6.100
  libavfilter     6. 82.100 /  6. 82.100
  libavresample   3.  5.  0 /  3.  5.  0
  libswscale      4.  6.100 /  4.  6.100
  libswresample   2.  7.100 /  2.  7.100
  libpostproc    54.  5.100 / 54.  5.100
[h264 @ 0x7f741a37a560] Reinit context to 640x368, pix_fmt: yuv420p
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/var/www/temp/film.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf57.71.100
  Duration: 00:06:19.80, start: 0.000000, bitrate: 451 kb/s
    Stream #0:0(und): Video: h264 (High), 1 reference frame (avc1 / 0x31637661), yuv420p(left), 640x358 (640x368), 313 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
[h264 @ 0x7f741a3bc700] Reinit context to 640x368, pix_fmt: yuv420p
[graph_1_in_0_1 @ 0x7f741a5315e0] tb:1/48000 samplefmt:fltp samplerate:48000 chlayout:0x3
[Parsed_scale_0 @ 0x7f741a54e000] w:1920 h:1080 flags:'bicubic' interl:0
[graph 0 input from stream 0:0 @ 0x7f741a54f6a0] w:640 h:358 pixfmt:yuv420p tb:1/15360 fr:30/1 sar:0/1 sws_param:flags=2
[Parsed_scale_0 @ 0x7f741a54e000] w:640 h:358 fmt:yuv420p sar:0/1 -> w:1920 h:1074 fmt:yuv420p sar:0/1 flags:0x4
[Parsed_pad_1 @ 0x7f741a54eac0] w:1920 h:1074 -> w:1920 h:1080 x:0 y:2 color:0x000000FF
[libx264 @ 0x7f741a5509e0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
[libx264 @ 0x7f741a5509e0] profile High, level 4.0
[libx264 @ 0x7f741a5509e0] 264 - core 148 r2795 aaa9aa8 - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - 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=6 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=25 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 '/var/www/temp/videoHD.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf57.71.100
    Stream #0:0(und): Video: h264 (libx264), 1 reference frame ([33][0][0][0] / 0x0021), yuv420p(left), 1920x1080, q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      encoder         : Lavc57.89.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
    Stream #0:1(und): Audio: aac (LC) ([64][0][0][0] / 0x0040), 48000 Hz, stereo, fltp, delay 1024, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
      encoder         : Lavc57.89.100 aac

This results in a file with no content.

When I run the command from the command line I need to add single quotes around the -vf video filters scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:x=(1920-iw)/2:y=(1080-ih)/2:color=black so the whole command becomes:

ffmpeg -y -loglevel verbose -i /var/www/temp/film.mp4 -vf 'scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:x=(1920-iw)/2:y=(1080-ih)/2:color=black' /var/www/temp/videoHD.mp4

Running this command gives the required result.

ffmpeg version 3.3.4-2~16.04.york0 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.4) 20160609
  configuration: --prefix=/usr --extra-version='2~16.04.york0' --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  libavutil      55. 58.100 / 55. 58.100
  libavcodec     57. 89.100 / 57. 89.100
  libavformat    57. 71.100 / 57. 71.100
  libavdevice    57.  6.100 / 57.  6.100
  libavfilter     6. 82.100 /  6. 82.100
  libavresample   3.  5.  0 /  3.  5.  0
  libswscale      4.  6.100 /  4.  6.100
  libswresample   2.  7.100 /  2.  7.100
  libpostproc    54.  5.100 / 54.  5.100
[h264 @ 0x7f3a55c17560] Reinit context to 640x368, pix_fmt: yuv420p
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/var/www/temp/film.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf57.71.100
  Duration: 00:06:19.80, start: 0.000000, bitrate: 451 kb/s
    Stream #0:0(und): Video: h264 (High), 1 reference frame (avc1 / 0x31637661), yuv420p(left), 640x358 (640x368), 313 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
[h264 @ 0x7f3a55c59700] Reinit context to 640x368, pix_fmt: yuv420p
[graph_1_in_0_1 @ 0x7f3a55dce5e0] tb:1/48000 samplefmt:fltp samplerate:48000 chlayout:0x3
[Parsed_scale_0 @ 0x7f3a55deb000] w:1920 h:1080 flags:'bicubic' interl:0
[graph 0 input from stream 0:0 @ 0x7f3a55dec6a0] w:640 h:358 pixfmt:yuv420p tb:1/15360 fr:30/1 sar:0/1 sws_param:flags=2
[Parsed_scale_0 @ 0x7f3a55deb000] w:640 h:358 fmt:yuv420p sar:0/1 -> w:1920 h:1074 fmt:yuv420p sar:0/1 flags:0x4
[Parsed_pad_1 @ 0x7f3a55debac0] w:1920 h:1074 -> w:1920 h:1080 x:0 y:2 color:0x000000FF
[libx264 @ 0x7f3a55ded9e0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
[libx264 @ 0x7f3a55ded9e0] profile High, level 4.0
[libx264 @ 0x7f3a55ded9e0] 264 - core 148 r2795 aaa9aa8 - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - 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=6 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=25 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 '/var/www/temp/videoHD.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf57.71.100
    Stream #0:0(und): Video: h264 (libx264), 1 reference frame ([33][0][0][0] / 0x0021), yuv420p(left), 1920x1080, q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      encoder         : Lavc57.89.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
    Stream #0:1(und): Audio: aac (LC) ([64][0][0][0] / 0x0040), 48000 Hz, stereo, fltp, delay 1024, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
      encoder         : Lavc57.89.100 aac
frame=   46 fps=0.0 q=0.0 size=       0kB time=00:00:01.62 bitrate=   0.0kbits/s
frame=   59 fps= 47 q=29.0 size=     116kB time=00:00:02.04 bitrate= 464.8kbits/
frame=   74 fps= 41 q=29.0 size=     223kB time=00:00:02.56 bitrate= 714.8kbits/
frame=   87 fps= 35 q=29.0 size=     344kB time=00:00:02.98 bitrate= 942.4kbits/
frame=   98 fps= 33 q=29.0 size=     427kB time=00:00:03.34 bitrate=1043.4kbits/
    blah
    blah
    blah
frame=11347 fps= 21 q=29.0 size=   97550kB time=00:06:18.32 bitrate=2112.3kbits/
frame=11363 fps= 21 q=29.0 size=   97713kB time=00:06:18.85 bitrate=2112.8kbits/
frame=11380 fps= 21 q=29.0 size=   97795kB time=00:06:19.41 bitrate=2111.5kbits/
No more output streams to write to, finishing.
frame=11392 fps= 21 q=-1.0 Lsize=   98519kB time=00:06:19.77 bitrate=2125.1kbits/s speed=0.69x    
video:92124kB audio:5986kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.416313%
Input file #0 (/var/www/temp/film.mp4):
  Input stream #0:0 (video): 11392 packets read (14892948 bytes); 11392 frames decoded; 
  Input stream #0:1 (audio): 17803 packets read (6112540 bytes); 17802 frames decoded (18229248 samples); 
  Total: 29195 packets (21005488 bytes) demuxed
Output file #0 (/var/www/temp/videoHD.mp4):
  Output stream #0:0 (video): 11392 frames encoded; 11392 packets muxed (94334785 bytes); 
  Output stream #0:1 (audio): 17802 frames encoded (18229248 samples); 17803 packets muxed (6129981 bytes); 
  Total: 29195 packets (100464766 bytes) muxed
[libx264 @ 0x7f3a55ded9e0] frame I:74    Avg QP:19.08  size: 51540
[libx264 @ 0x7f3a55ded9e0] frame P:3506  Avg QP:21.34  size: 19348
[libx264 @ 0x7f3a55ded9e0] frame B:7812  Avg QP:24.07  size:  2904
[libx264 @ 0x7f3a55ded9e0] consecutive B-frames:  1.3% 20.2%  4.6% 73.9%
[libx264 @ 0x7f3a55ded9e0] mb I  I16..4: 19.7% 73.6%  6.7%
[libx264 @ 0x7f3a55ded9e0] mb P  I16..4:  3.2%  6.4%  0.1%  P16..4: 52.5%  7.6%  2.6%  0.0%  0.0%    skip:27.6%
[libx264 @ 0x7f3a55ded9e0] mb B  I16..4:  0.2%  0.2%  0.0%  B16..8: 23.2%  0.4%  0.0%  direct: 0.5%  skip:75.5%  L0:51.8% L1:46.6% BI: 1.6%
[libx264 @ 0x7f3a55ded9e0] 8x8 transform intra:66.4% inter:94.0%
[libx264 @ 0x7f3a55ded9e0] coded y,uvDC,uvAC intra: 33.6% 53.4% 7.3% inter: 5.3% 14.2% 0.0%
[libx264 @ 0x7f3a55ded9e0] i16 v,h,dc,p: 22% 27%  5% 46%
[libx264 @ 0x7f3a55ded9e0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 29% 19% 20%  4%  7%  7%  7%  5%  4%
[libx264 @ 0x7f3a55ded9e0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 31% 28% 11%  3%  9%  7%  6%  3%  2%
[libx264 @ 0x7f3a55ded9e0] i8c dc,h,v,p: 49% 21% 20% 10%
[libx264 @ 0x7f3a55ded9e0] Weighted P-Frames: Y:0.5% UV:0.1%
[libx264 @ 0x7f3a55ded9e0] ref P L0: 63.4%  8.9% 21.4%  6.3%  0.0%
[libx264 @ 0x7f3a55ded9e0] ref B L0: 89.3%  9.1%  1.6%
[libx264 @ 0x7f3a55ded9e0] ref B L1: 98.1%  1.9%
[libx264 @ 0x7f3a55ded9e0] kb/s:1987.38
[aac @ 0x7f3a55deee80] Qavg: 1160.814

and the resulting video is fine.

Any ideas?

Cheers,

Stu

Edit

It was suggested that I use a new function to do much the same thing. So I added the following function and used it for the command that I'm having trouble with:

def ffmpegPro(args):
    err = None
    for i, arg in enumerate(args):
        if(" " in arg or "(" in arg or "[" in arg):
            args[i] = "\"" + arg + "\""
    command = [
        ffmpegcmd, '-y',
        '-loglevel', loglevel
    ] + args
    commandStr = " ".join(command)
    print("\n\n\n")
    print(command)
    print("\n\n\n")
    print(commandStr)
    ffmpeg = subprocess.Popen(commandStr, stderr=subprocess.PIPE, stdout=subprocess.PIPE, universal_newlines=True, shell=True)
    while err == None:
        out, err = ffmpeg.communicate()
        time.sleep(1)
    if ffmpeg.returncode == 0 and all([os.path.exists(f) for f in (videoStorage['data_small'], videoStorage['data_big'])]):
        print("Job done.")
    else:
        print("ERROR")
        print(err)

The resulting command can now be used in python or at the command line without needing to be changed at all. The command is:

ffmpeg -y -loglevel verbose -i /var/www/temp/film.mp4 -vf "scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:x=(1920-iw)/2:y=(1080-ih)/2:color=black" /var/www/temp/videoHD.mp4

The result when executed in python is

ffmpeg version 3.3.4-2~16.04.york0 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.4) 20160609
  configuration: --prefix=/usr --extra-version='2~16.04.york0' --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  libavutil      55. 58.100 / 55. 58.100
  libavcodec     57. 89.100 / 57. 89.100
  libavformat    57. 71.100 / 57. 71.100
  libavdevice    57.  6.100 / 57.  6.100
  libavfilter     6. 82.100 /  6. 82.100
  libavresample   3.  5.  0 /  3.  5.  0
  libswscale      4.  6.100 /  4.  6.100
  libswresample   2.  7.100 /  2.  7.100
  libpostproc    54.  5.100 / 54.  5.100
[h264 @ 0x7fb75053d560] Reinit context to 640x368, pix_fmt: yuv420p
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/var/www/temp/film.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf57.71.100
  Duration: 00:06:19.80, start: 0.000000, bitrate: 451 kb/s
    Stream #0:0(und): Video: h264 (High), 1 reference frame (avc1 / 0x31637661), yuv420p(left), 640x358 (640x368), 313 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
[h264 @ 0x7fb75057f700] Reinit context to 640x368, pix_fmt: yuv420p
[graph_1_in_0_1 @ 0x7fb7506f45e0] tb:1/48000 samplefmt:fltp samplerate:48000 chlayout:0x3
[Parsed_scale_0 @ 0x7fb750711000] w:1920 h:1080 flags:'bicubic' interl:0
[graph 0 input from stream 0:0 @ 0x7fb7507126a0] w:640 h:358 pixfmt:yuv420p tb:1/15360 fr:30/1 sar:0/1 sws_param:flags=2
[Parsed_scale_0 @ 0x7fb750711000] w:640 h:358 fmt:yuv420p sar:0/1 -> w:1920 h:1074 fmt:yuv420p sar:0/1 flags:0x4
[Parsed_pad_1 @ 0x7fb750711ac0] w:1920 h:1074 -> w:1920 h:1080 x:0 y:2 color:0x000000FF
[libx264 @ 0x7fb7507139e0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
[libx264 @ 0x7fb7507139e0] profile High, level 4.0
[libx264 @ 0x7fb7507139e0] 264 - core 148 r2795 aaa9aa8 - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - 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=6 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=25 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 '/var/www/temp/videoHD.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf57.71.100
    Stream #0:0(und): Video: h264 (libx264), 1 reference frame ([33][0][0][0] / 0x0021), yuv420p(left), 1920x1080, q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      encoder         : Lavc57.89.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
    Stream #0:1(und): Audio: aac (LC) ([64][0][0][0] / 0x0040), 48000 Hz, stereo, fltp, delay 1024, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
      encoder         : Lavc57.89.100 aac
Killed

Note the Killed at the end. Is this significant and why is it only happening when executed in the script?

Here is the output from the command line which results in a successful video file.

ffmpeg version 3.3.4-2~16.04.york0 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.4) 20160609
  configuration: --prefix=/usr --extra-version='2~16.04.york0' --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  libavutil      55. 58.100 / 55. 58.100
  libavcodec     57. 89.100 / 57. 89.100
  libavformat    57. 71.100 / 57. 71.100
  libavdevice    57.  6.100 / 57.  6.100
  libavfilter     6. 82.100 /  6. 82.100
  libavresample   3.  5.  0 /  3.  5.  0
  libswscale      4.  6.100 /  4.  6.100
  libswresample   2.  7.100 /  2.  7.100
  libpostproc    54.  5.100 / 54.  5.100
[h264 @ 0x7fb52cfb3560] Reinit context to 640x368, pix_fmt: yuv420p
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/var/www/temp/film.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf57.71.100
  Duration: 00:06:19.80, start: 0.000000, bitrate: 451 kb/s
    Stream #0:0(und): Video: h264 (High), 1 reference frame (avc1 / 0x31637661), yuv420p(left), 640x358 (640x368), 313 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
[h264 @ 0x7fb52cff5700] Reinit context to 640x368, pix_fmt: yuv420p
[graph_1_in_0_1 @ 0x7fb52d16a5e0] tb:1/48000 samplefmt:fltp samplerate:48000 chlayout:0x3
[Parsed_scale_0 @ 0x7fb52d187000] w:1920 h:1080 flags:'bicubic' interl:0
[graph 0 input from stream 0:0 @ 0x7fb52d1886a0] w:640 h:358 pixfmt:yuv420p tb:1/15360 fr:30/1 sar:0/1 sws_param:flags=2
[Parsed_scale_0 @ 0x7fb52d187000] w:640 h:358 fmt:yuv420p sar:0/1 -> w:1920 h:1074 fmt:yuv420p sar:0/1 flags:0x4
[Parsed_pad_1 @ 0x7fb52d187ac0] w:1920 h:1074 -> w:1920 h:1080 x:0 y:2 color:0x000000FF
[libx264 @ 0x7fb52d1899e0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
[libx264 @ 0x7fb52d1899e0] profile High, level 4.0
[libx264 @ 0x7fb52d1899e0] 264 - core 148 r2795 aaa9aa8 - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - 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=6 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=25 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 '/var/www/temp/videoHD.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf57.71.100
    Stream #0:0(und): Video: h264 (libx264), 1 reference frame ([33][0][0][0] / 0x0021), yuv420p(left), 1920x1080, q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      encoder         : Lavc57.89.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
    Stream #0:1(und): Audio: aac (LC) ([64][0][0][0] / 0x0040), 48000 Hz, stereo, fltp, delay 1024, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
      encoder         : Lavc57.89.100 aac
frame=   47 fps=0.0 q=0.0 size=       0kB time=00:00:01.66 bitrate=   0.0kbits/s
frame=   59 fps= 41 q=29.0 size=     116kB time=00:00:02.04 bitrate= 464.8kbits/
frame=   71 fps= 35 q=29.0 size=     201kB time=00:00:02.45 bitrate= 671.3kbits/
frame=   80 fps= 31 q=29.0 size=     276kB time=00:00:02.75 bitrate= 822.0kbits/
    Blah
    Blah
    Blah
frame=11337 fps= 21 q=29.0 size=   97503kB time=00:06:17.98 bitrate=2113.2kbits/
frame=11351 fps= 21 q=26.0 size=   97572kB time=00:06:18.45 bitrate=2112.1kbits/
frame=11371 fps= 21 q=29.0 size=   97745kB time=00:06:19.11 bitrate=2112.1kbits/
frame=11390 fps= 21 q=29.0 size=   97852kB time=00:06:19.73 bitrate=2111.0kbits/
No more output streams to write to, finishing.
frame=11392 fps= 21 q=-1.0 Lsize=   98519kB time=00:06:19.77 bitrate=2125.1kbits/s speed=0.688x    
video:92124kB audio:5986kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.416313%
Input file #0 (/var/www/temp/film.mp4):
  Input stream #0:0 (video): 11392 packets read (14892948 bytes); 11392 frames decoded; 
  Input stream #0:1 (audio): 17803 packets read (6112540 bytes); 17802 frames decoded (18229248 samples); 
  Total: 29195 packets (21005488 bytes) demuxed
Output file #0 (/var/www/temp/videoHD.mp4):
  Output stream #0:0 (video): 11392 frames encoded; 11392 packets muxed (94334785 bytes); 
  Output stream #0:1 (audio): 17802 frames encoded (18229248 samples); 17803 packets muxed (6129981 bytes); 
  Total: 29195 packets (100464766 bytes) muxed
[libx264 @ 0x7fb52d1899e0] frame I:74    Avg QP:19.08  size: 51540
[libx264 @ 0x7fb52d1899e0] frame P:3506  Avg QP:21.34  size: 19348
[libx264 @ 0x7fb52d1899e0] frame B:7812  Avg QP:24.07  size:  2904
[libx264 @ 0x7fb52d1899e0] consecutive B-frames:  1.3% 20.2%  4.6% 73.9%
[libx264 @ 0x7fb52d1899e0] mb I  I16..4: 19.7% 73.6%  6.7%
[libx264 @ 0x7fb52d1899e0] mb P  I16..4:  3.2%  6.4%  0.1%  P16..4: 52.5%  7.6%  2.6%  0.0%  0.0%    skip:27.6%
[libx264 @ 0x7fb52d1899e0] mb B  I16..4:  0.2%  0.2%  0.0%  B16..8: 23.2%  0.4%  0.0%  direct: 0.5%  skip:75.5%  L0:51.8% L1:46.6% BI: 1.6%
[libx264 @ 0x7fb52d1899e0] 8x8 transform intra:66.4% inter:94.0%
[libx264 @ 0x7fb52d1899e0] coded y,uvDC,uvAC intra: 33.6% 53.4% 7.3% inter: 5.3% 14.2% 0.0%
[libx264 @ 0x7fb52d1899e0] i16 v,h,dc,p: 22% 27%  5% 46%
[libx264 @ 0x7fb52d1899e0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 29% 19% 20%  4%  7%  7%  7%  5%  4%
[libx264 @ 0x7fb52d1899e0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 31% 28% 11%  3%  9%  7%  6%  3%  2%
[libx264 @ 0x7fb52d1899e0] i8c dc,h,v,p: 49% 21% 20% 10%
[libx264 @ 0x7fb52d1899e0] Weighted P-Frames: Y:0.5% UV:0.1%
[libx264 @ 0x7fb52d1899e0] ref P L0: 63.4%  8.9% 21.4%  6.3%  0.0%
[libx264 @ 0x7fb52d1899e0] ref B L0: 89.3%  9.1%  1.6%
[libx264 @ 0x7fb52d1899e0] ref B L1: 98.1%  1.9%
[libx264 @ 0x7fb52d1899e0] kb/s:1987.38
[aac @ 0x7fb52d18ae80] Qavg: 1160.814

Any more ideas why this is being handled differently in python as opposed to the command line?

I'm believe this is a version issue and that is why the below answer did not work for me, things were fine before I upgraded but since then a lot of things have been playing up. I upgraded both ffmpeg and python versions and don't really want to go back if it can be avoided.

Thanks,

Stu