加快视频到图像的转换速度

Question

我用

call(['avconv', '-i', 'video.mp4', '-vsync', '1','-r', '1','-an','-y','%5d.jpg'])

在Python中

。它有效，但它实时通过视频文件。如何加快速度，所以总共得到60张图片，视频文件的每一秒都不需要1分钟而是更少。

Answer 1

以下Python代码尽可能快地提取60秒的帧，并将它们作为JPEG文件输出到当前目录中。

源

from subprocess import call

call([
    'avconv', '-i', 'video.mp4', 
    '-vsync', '1', 
    '-r', '1',
    '-an', '-y',
    '-t', '60',                 # 60 seconds = 60 pictures
    '%5d.jpg',
])

输出

avconv version 0.8.9-6:0.8.9-0ubuntu0.13.10.1, Copyright (c) 2000-2013 the Libav developers
  built on Nov  9 2013 19:09:46 with gcc 4.8.1
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x14bbe00] multiple edit list entries, a/v desync might occur, patch welcome
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2mp41
    encoder         : Lavf53.21.1
  Duration: 01:59:16.23, start: 0.000000, bitrate: 1153 kb/s
    Stream #0.0(und): Video: mpeg4 (Advanced Simple Profile), yuv420p, 480x368 [PAR 1:1 DAR 30:23], 1016 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 23.98 tbc
    Stream #0.1(und): Audio: aac, 48000 Hz, mono, s16, 63 kb/s
    Stream #0.2(und): Audio: aac, 48000 Hz, mono, s16, 64 kb/s
Incompatible pixel format 'yuv420p' for codec 'mjpeg', auto-selecting format 'yuvj420p'
[buffer @ 0x1670a20] w:480 h:368 pixfmt:yuv420p
[avsink @ 0x147f6a0] auto-inserting filter 'auto-inserted scaler 0' between the filter 'src' and the filter 'out'
[scale @ 0x14bf520] w:480 h:368 fmt:yuv420p -> w:480 h:368 fmt:yuvj420p flags:0x4
Output #0, image2, to '%5d.jpg':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2mp41
    encoder         : Lavf53.21.1
    Stream #0.0(und): Video: mjpeg, yuvj420p, 480x368 [PAR 1:1 DAR 30:23], q=2-31, 200 kb/s, 90k tbn, 1 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (mpeg4 -> mjpeg)
Press ctrl-c to stop encoding
frame=   62 fps= 37 q=11.2 Lsize=      -0kB time=62.00 bitrate=  -0.0kbits/s dup=0 drop=1375    
video:1784kB audio:0kB global headers:0kB muxing overhead -100.001204%