FFMPEG 不能从 Python subprocess.Popen 工作，但可以从命令行工作

Question

我正在尝试从 python 3.5.2 中运行 FFMPEG 脚本。 FFMPEG 命令在命令行中运行良好，但在 python 脚本中失败。

我用来执行FFMPEG命令的函数是

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)

args 的值为：

['-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']

这样传递给subprocess.Popen的结果命令是：

['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']

loglevel 的值为verbose 仅用于故障排除，但旨在以fatal 运行。还有一些print 命令仅用于故障排除。

想要提高分辨率的原因是为了以后可以与更高分辨率的视频相结合。

在python内运行时的结果是：

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

这会导致文件没有内容。

当我从命令行运行命令时，我需要在 -vf 视频过滤器 scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:x=(1920-iw)/2:y=(1080-ih)/2:color=black 周围添加单引号，因此整个命令变为：

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

运行此命令会给出所需的结果。

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

生成的视频很好。

有什么想法吗？

干杯，

学习

编辑

有人建议我使用一个新函数来做同样的事情。所以我添加了以下函数并将其用于我遇到问题的命令：

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)

生成的命令现在可以在python 或命令行中使用，根本不需要更改。命令是：

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

在python中执行的结果是

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

注意最后的Killed。这很重要吗？为什么只有在脚本中执行时才会发生？

这里是命令行的输出，它会生成一个成功的视频文件。

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

还有什么想法为什么在python 中处理方式与命令行不同？

我相信这是一个版本问题，这就是为什么下面的答案对我不起作用的原因，在我升级之前一切都很好，但从那以后很多事情都在发生。我升级了ffmpeg 和python 两个版本，如果可以避免的话，我真的不想回去。

谢谢，

学习

Answer 1

我正在通过这样的子进程做 ffmpeg：

1.) ffmpeg 命令作为字符串而不是列表。
2.) -vf 选项的双引号。
3.) shell=True.
4.) -y 强制 ffmpeg 覆盖新文件。
5.) Python 2.7/Python3.6 上的 ffmpeg 版本 3.4。

cmd = "ffmpeg -threads %s -i %s " % (_threads, _videoFile['path'])
for fmt in ('640:360', '1024:576'):
    cmd += ' ... alot of string concentration here ...' 

print "ffmpeg command is:"
print cmd
print ""

cmd = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
out, err = cmd.communicate()
if cmd.returncode == 0 and all([os.path.exists(f) for f in (videoStorage['data_small'], videoStorage['data_big'])]):
    print "Job done."
else:
    print "ERROR"
    print out

输出：

ffmpeg command is:
ffmpeg -threads 2 -i /home/f3k/mini.elapsed.mov    -to 0:00:41   -vf "boxblur=enable='between(t,5.646,23.353)'"  -s 640:360 -sn -codec:a copy -q:v 1 -threads 2 -y /tmp/result.small.mp4    -to 0:00:41   -vf "boxblur=enable='between(t,5.646,23.353)'"  -s 1024:576 -sn -codec:a copy -q:v 1 -threads 2 -y /tmp/result.big.mp4 

Job done.