I'm using ffmpeg to extract frames from video, but the process is so slow. Looking at CPU usage I see that ffmpeg use only 50% of my CPU. I've tried also to add -threads 4, but it seems it doesn't have any effect. I need to maximize the speed of this process. How can I do it?
Update: So I run a test, I tried first to convert one video alone, having this result:
ffmpeg version N-71959-g9253cc4 Copyright (c) 2000-2015 the FFmpeg developers
built with gcc 4.9.2 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-lzma --enable-decklink --enable-zlib
libavutil 54. 23.101 / 54. 23.101
libavcodec 56. 37.102 / 56. 37.102
libavformat 56. 32.100 / 56. 32.100
libavdevice 56. 4.100 / 56. 4.100
libavfilter 5. 16.101 / 5. 16.101
libswscale 3. 1.101 / 3. 1.101
libswresample 1. 1.100 / 1. 1.100
libpostproc 53. 3.100 / 53. 3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'C:\1.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf55.33.100
Duration: 00:30:23.13, start: 0.000000, bitrate: 573 kb/s
Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 640x360 [SAR 1:1 DAR 16:9], 501 kb/s, 29.97 fps, 29.97 tbr, 11988 tbn, 59.94 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, mono, fltp, 32 kb/s (default)
Metadata:
handler_name : SoundHandler
Stream #0:2(und): Data: none (rtp / 0x20707472), 26 kb/s (default)
Metadata:
creation_time : 2014-08-27 16:05:35
handler_name : GPAC ISO Hint Handler
Stream #0:3(und): Data: none (rtp / 0x20707472), 7 kb/s (default)
Metadata:
creation_time : 2014-08-27 16:05:53
handler_name : GPAC ISO Hint Handler
[swscaler @ 0000000002e63360] deprecated pixel format used, make sure you did set range correctly
Output #0, image2, to 'C:\TEMP\1-%d.jpg':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf56.32.100
Stream #0:0(und): Video: mjpeg, yuvj420p(pc), 640x360 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 1 fps, 1 tbn, 1 tbc (default)
Metadata:
handler_name : VideoHandler
encoder : Lavc56.37.102 mjpeg
Stream mapping:
Stream #0:0 -> #0:0 (h264 (native) -> mjpeg (native))
Press [q] to stop, [?] for help
frame= 15 fps=0.0 q=1.6 size=N/A time=00:00:15.00 bitrate=N/A dup=0 drop=384
frame= 28 fps= 28 q=1.6 size=N/A time=00:00:28.00 bitrate=N/A dup=0 drop=763
frame= 42 fps= 28 q=1.6 size=N/A time=00:00:42.00 bitrate=N/A dup=0 drop=1172
frame= 55 fps= 27 q=1.6 size=N/A time=00:00:55.00 bitrate=N/A dup=0 drop=1529
frame= 67 fps= 27 q=1.6 size=N/A time=00:01:07.00 bitrate=N/A dup=0 drop=1896
frame= 80 fps= 27 q=1.6 size=N/A time=00:01:20.00 bitrate=N/A dup=0 drop=2267
frame= 93 fps= 27 q=1.6 size=N/A time=00:01:33.00 bitrate=N/A dup=0 drop=2651
frame= 106 fps= 26 q=1.6 size=N/A time=00:01:46.00 bitrate=N/A dup=0 drop=3025
frame= 119 fps= 26 q=1.6 size=N/A time=00:01:59.00 bitrate=N/A dup=0 drop=3386
frame= 131 fps= 26 q=1.6 size=N/A time=00:02:11.00 bitrate=N/A dup=0 drop=3757
frame= 144 fps= 26 q=1.6 size=N/A time=00:02:24.00 bitrate=N/A dup=0 drop=4124
frame= 157 fps= 26 q=1.6 size=N/A time=00:02:37.00 bitrate=N/A dup=0 drop=4487
frame= 169 fps= 26 q=1.6 size=N/A time=00:02:49.00 bitrate=N/A dup=0 drop=4852
frame= 182 fps= 26 q=1.6 size=N/A time=00:03:02.00 bitrate=N/A dup=0 drop=5226
frame= 195 fps= 26 q=1.6 size=N/A time=00:03:15.00 bitrate=N/A dup=0 drop=5593
frame= 209 fps= 26 q=1.6 size=N/A time=00:03:29.00 bitrate=N/A dup=0 drop=5990
frame= 222 fps= 26 q=1.6 size=N/A time=00:03:42.00 bitrate=N/A dup=0 drop=6367
frame= 235 fps= 26 q=1.6 size=N/A time=00:03:55.00 bitrate=N/A dup=0 drop=6753
frame= 248 fps= 26 q=1.6 size=N/A time=00:04:08.00 bitrate=N/A dup=0 drop=7131
frame= 261 fps= 26 q=1.6 size=N/A time=00:04:21.00 bitrate=N/A dup=0 drop=7497
frame= 274 fps= 26 q=1.6 size=N/A time=00:04:34.00 bitrate=N/A dup=0 drop=7873
frame= 287 fps= 26 q=1.6 size=N/A time=00:04:47.00 bitrate=N/A dup=0 drop=8255
frame= 300 fps= 26 q=1.6 size=N/A time=00:05:00.00 bitrate=N/A dup=0 drop=8644
frame= 314 fps= 26 q=1.6 size=N/A time=00:05:14.00 bitrate=N/A dup=0 drop=9036
frame= 328 fps= 26 q=1.6 size=N/A time=00:05:28.00 bitrate=N/A dup=0 drop=9438
frame= 340 fps= 26 q=1.6 size=N/A time=00:05:40.00 bitrate=N/A dup=0 drop=9813
frame= 354 fps= 26 q=1.6 size=N/A time=00:05:54.00 bitrate=N/A dup=0 drop=10205
frame= 367 fps= 26 q=1.6 size=N/A time=00:06:07.00 bitrate=N/A dup=0 drop=10585
frame= 380 fps= 26 q=1.6 size=N/A time=00:06:20.00 bitrate=N/A dup=0 drop=10961
frame= 394 fps= 26 q=1.6 size=N/A time=00:06:34.00 bitrate=N/A dup=0 drop=11360
frame= 406 fps= 26 q=1.6 size=N/A time=00:06:46.00 bitrate=N/A dup=0 drop=11712
frame= 420 fps= 26 q=1.6 size=N/A time=00:07:00.00 bitrate=N/A dup=0 drop=12103
frame= 434 fps= 26 q=1.6 size=N/A time=00:07:14.00 bitrate=N/A dup=0 drop=12509
frame= 447 fps= 26 q=1.6 size=N/A time=00:07:27.00 bitrate=N/A dup=0 drop=12888
frame= 460 fps= 26 q=1.6 size=N/A time=00:07:40.00 bitrate=N/A dup=0 drop=13267
frame= 473 fps= 26 q=1.6 size=N/A time=00:07:53.00 bitrate=N/A dup=0 drop=13640
frame= 486 fps= 26 q=1.6 size=N/A time=00:08:06.00 bitrate=N/A dup=0 drop=14036
frame= 500 fps= 26 q=1.6 size=N/A time=00:08:20.00 bitrate=N/A dup=0 drop=14421
frame= 513 fps= 26 q=1.6 size=N/A time=00:08:33.00 bitrate=N/A dup=0 drop=14808
frame= 526 fps= 26 q=1.6 size=N/A time=00:08:46.00 bitrate=N/A dup=0 drop=15197
frame= 540 fps= 26 q=1.6 size=N/A time=00:09:00.00 bitrate=N/A dup=0 drop=15579
frame= 552 fps= 26 q=1.6 size=N/A time=00:09:12.00 bitrate=N/A dup=0 drop=15948
frame= 565 fps= 26 q=1.6 size=N/A time=00:09:25.00 bitrate=N/A dup=0 drop=16321
frame= 579 fps= 26 q=1.6 size=N/A time=00:09:39.00 bitrate=N/A dup=0 drop=16725
frame= 592 fps= 26 q=1.6 size=N/A time=00:09:52.00 bitrate=N/A dup=0 drop=17097
frame= 605 fps= 26 q=1.6 size=N/A time=00:10:05.00 bitrate=N/A dup=0 drop=17462
frame= 618 fps= 26 q=1.6 size=N/A time=00:10:18.00 bitrate=N/A dup=0 drop=17851
frame= 631 fps= 26 q=1.6 size=N/A time=00:10:31.00 bitrate=N/A dup=0 drop=18225
frame= 644 fps= 26 q=1.6 size=N/A time=00:10:44.00 bitrate=N/A dup=0 drop=18607
frame= 657 fps= 26 q=1.6 size=N/A time=00:10:57.00 bitrate=N/A dup=0 drop=18969
frame= 669 fps= 26 q=1.6 size=N/A time=00:11:09.00 bitrate=N/A dup=0 drop=19333
frame= 681 fps= 26 q=1.6 size=N/A time=00:11:21.00 bitrate=N/A dup=0 drop=19681
frame= 693 fps= 26 q=1.6 size=N/A time=00:11:33.00 bitrate=N/A dup=0 drop=20026
frame= 706 fps= 26 q=1.6 size=N/A time=00:11:46.00 bitrate=N/A dup=0 drop=20402
frame= 716 fps= 26 q=1.6 size=N/A time=00:11:56.00 bitrate=N/A dup=0 drop=20691
frame= 726 fps= 26 q=1.6 size=N/A time=00:12:06.00 bitrate=N/A dup=0 drop=20985
frame= 738 fps= 26 q=1.6 size=N/A time=00:12:18.00 bitrate=N/A dup=0 drop=21317
frame= 751 fps= 26 q=1.6 size=N/A time=00:12:31.00 bitrate=N/A dup=0 drop=21692
frame= 763 fps= 26 q=1.6 size=N/A time=00:12:43.00 bitrate=N/A dup=0 drop=22049
frame= 775 fps= 26 q=1.6 size=N/A time=00:12:55.00 bitrate=N/A dup=0 drop=22403
frame= 788 fps= 26 q=1.6 size=N/A time=00:13:08.00 bitrate=N/A dup=0 drop=22764
frame= 801 fps= 26 q=1.6 size=N/A time=00:13:21.00 bitrate=N/A dup=0 drop=23149
frame= 814 fps= 26 q=1.6 size=N/A time=00:13:34.00 bitrate=N/A dup=0 drop=23540
frame= 828 fps= 26 q=1.6 size=N/A time=00:13:48.00 bitrate=N/A dup=0 drop=23937
frame= 841 fps= 26 q=1.6 size=N/A time=00:14:01.00 bitrate=N/A dup=0 drop=24315
frame= 854 fps= 26 q=1.6 size=N/A time=00:14:14.00 bitrate=N/A dup=0 drop=24694
frame= 867 fps= 26 q=1.6 size=N/A time=00:14:27.00 bitrate=N/A dup=0 drop=25071
frame= 881 fps= 26 q=1.6 size=N/A time=00:14:41.00 bitrate=N/A dup=0 drop=25458
frame= 894 fps= 26 q=1.6 size=N/A time=00:14:54.00 bitrate=N/A dup=0 drop=25844
frame= 908 fps= 26 q=1.6 size=N/A time=00:15:08.00 bitrate=N/A dup=0 drop=26240
frame= 923 fps= 26 q=1.6 size=N/A time=00:15:23.00 bitrate=N/A dup=0 drop=26675
frame= 935 fps= 26 q=1.6 size=N/A time=00:15:35.00 bitrate=N/A dup=0 drop=27038
frame= 949 fps= 26 q=1.6 size=N/A time=00:15:49.00 bitrate=N/A dup=0 drop=27431
frame= 961 fps= 26 q=1.6 size=N/A time=00:16:01.00 bitrate=N/A dup=0 drop=27776
frame= 973 fps= 26 q=1.6 size=N/A time=00:16:13.00 bitrate=N/A dup=0 drop=28125
frame= 985 fps= 26 q=1.6 size=N/A time=00:16:25.00 bitrate=N/A dup=0 drop=28477
frame= 998 fps= 26 q=1.6 size=N/A time=00:16:38.00 bitrate=N/A dup=0 drop=28848
frame= 1010 fps= 26 q=1.6 size=N/A time=00:16:50.00 bitrate=N/A dup=0 drop=29211
frame= 1023 fps= 26 q=1.6 size=N/A time=00:17:03.00 bitrate=N/A dup=0 drop=29572
frame= 1035 fps= 26 q=1.6 size=N/A time=00:17:15.00 bitrate=N/A dup=0 drop=29932
frame= 1047 fps= 26 q=1.6 size=N/A time=00:17:27.00 bitrate=N/A dup=0 drop=30294
frame= 1060 fps= 26 q=1.6 size=N/A time=00:17:40.00 bitrate=N/A dup=0 drop=30644
frame= 1072 fps= 26 q=1.6 size=N/A time=00:17:52.00 bitrate=N/A dup=0 drop=31004
frame= 1085 fps= 26 q=1.6 size=N/A time=00:18:05.00 bitrate=N/A dup=0 drop=31368
frame= 1097 fps= 26 q=1.6 size=N/A time=00:18:17.00 bitrate=N/A dup=0 drop=31742
frame= 1110 fps= 26 q=1.6 size=N/A time=00:18:30.00 bitrate=N/A dup=0 drop=32101
frame= 1123 fps= 26 q=1.6 size=N/A time=00:18:43.00 bitrate=N/A dup=0 drop=32493
frame= 1137 fps= 26 q=1.6 size=N/A time=00:18:57.00 bitrate=N/A dup=0 drop=32874
frame= 1150 fps= 26 q=1.6 size=N/A time=00:19:10.00 bitrate=N/A dup=0 drop=33251
frame= 1162 fps= 26 q=1.6 size=N/A time=00:19:22.00 bitrate=N/A dup=0 drop=33626
frame= 1175 fps= 26 q=1.6 size=N/A time=00:19:35.00 bitrate=N/A dup=0 drop=33990
frame= 1188 fps= 26 q=1.6 size=N/A time=00:19:48.00 bitrate=N/A dup=0 drop=34362
frame= 1201 fps= 26 q=1.6 size=N/A time=00:20:01.00 bitrate=N/A dup=0 drop=34739
frame= 1214 fps= 26 q=1.6 size=N/A time=00:20:14.00 bitrate=N/A dup=0 drop=35127
frame= 1228 fps= 26 q=1.6 size=N/A time=00:20:28.00 bitrate=N/A dup=0 drop=35521
frame= 1242 fps= 26 q=1.6 size=N/A time=00:20:42.00 bitrate=N/A dup=0 drop=35916
frame= 1254 fps= 26 q=1.6 size=N/A time=00:20:54.00 bitrate=N/A dup=0 drop=36281
frame= 1267 fps= 26 q=1.6 size=N/A time=00:21:07.00 bitrate=N/A dup=0 drop=36661
frame= 1280 fps= 26 q=1.6 size=N/A time=00:21:20.00 bitrate=N/A dup=0 drop=37017
frame= 1293 fps= 26 q=1.6 size=N/A time=00:21:33.00 bitrate=N/A dup=0 drop=37394
frame= 1306 fps= 26 q=1.6 size=N/A time=00:21:46.00 bitrate=N/A dup=0 drop=37786
frame= 1318 fps= 26 q=1.6 size=N/A time=00:21:58.00 bitrate=N/A dup=0 drop=38142
frame= 1332 fps= 26 q=1.6 size=N/A time=00:22:12.00 bitrate=N/A dup=0 drop=38526
frame= 1346 fps= 26 q=1.6 size=N/A time=00:22:26.00 bitrate=N/A dup=0 drop=38929
frame= 1358 fps= 26 q=1.6 size=N/A time=00:22:38.00 bitrate=N/A dup=0 drop=39303
frame= 1371 fps= 26 q=1.6 size=N/A time=00:22:51.00 bitrate=N/A dup=0 drop=39676
frame= 1384 fps= 26 q=1.6 size=N/A time=00:23:04.00 bitrate=N/A dup=0 drop=40046
frame= 1398 fps= 26 q=1.6 size=N/A time=00:23:18.00 bitrate=N/A dup=0 drop=40438
frame= 1411 fps= 26 q=1.6 size=N/A time=00:23:31.00 bitrate=N/A dup=0 drop=40818
frame= 1424 fps= 26 q=1.6 size=N/A time=00:23:44.00 bitrate=N/A dup=0 drop=41202
frame= 1437 fps= 26 q=1.6 size=N/A time=00:23:57.00 bitrate=N/A dup=0 drop=41589
frame= 1451 fps= 26 q=1.6 size=N/A time=00:24:11.00 bitrate=N/A dup=0 drop=41971
frame= 1463 fps= 26 q=1.6 size=N/A time=00:24:23.00 bitrate=N/A dup=0 drop=42340
frame= 1477 fps= 26 q=1.6 size=N/A time=00:24:37.00 bitrate=N/A dup=0 drop=42724
frame= 1490 fps= 26 q=1.6 size=N/A time=00:24:50.00 bitrate=N/A dup=0 drop=43129
frame= 1503 fps= 26 q=1.6 size=N/A time=00:25:03.00 bitrate=N/A dup=0 drop=43500
frame= 1516 fps= 26 q=1.6 size=N/A time=00:25:16.00 bitrate=N/A dup=0 drop=43869
frame= 1530 fps= 26 q=1.6 size=N/A time=00:25:30.00 bitrate=N/A dup=0 drop=44260
frame= 1543 fps= 26 q=1.6 size=N/A time=00:25:43.00 bitrate=N/A dup=0 drop=44646
frame= 1556 fps= 26 q=1.6 size=N/A time=00:25:56.00 bitrate=N/A dup=0 drop=45033
frame= 1569 fps= 26 q=1.6 size=N/A time=00:26:09.00 bitrate=N/A dup=0 drop=45393
frame= 1582 fps= 26 q=1.6 size=N/A time=00:26:22.00 bitrate=N/A dup=0 drop=45766
frame= 1594 fps= 26 q=1.6 size=N/A time=00:26:34.00 bitrate=N/A dup=0 drop=46139
frame= 1607 fps= 26 q=1.6 size=N/A time=00:26:47.00 bitrate=N/A dup=0 drop=46498
frame= 1620 fps= 26 q=1.6 size=N/A time=00:27:00.00 bitrate=N/A dup=0 drop=46874
frame= 1633 fps= 26 q=1.6 size=N/A time=00:27:13.00 bitrate=N/A dup=0 drop=47247
frame= 1645 fps= 26 q=1.6 size=N/A time=00:27:25.00 bitrate=N/A dup=0 drop=47609
frame= 1659 fps= 26 q=1.6 size=N/A time=00:27:39.00 bitrate=N/A dup=0 drop=48000
frame= 1671 fps= 26 q=1.6 size=N/A time=00:27:51.00 bitrate=N/A dup=0 drop=48362
frame= 1684 fps= 26 q=1.6 size=N/A time=00:28:04.00 bitrate=N/A dup=0 drop=48748
frame= 1697 fps= 26 q=1.6 size=N/A time=00:28:17.00 bitrate=N/A dup=0 drop=49103
frame= 1710 fps= 26 q=1.6 size=N/A time=00:28:30.00 bitrate=N/A dup=0 drop=49474
frame= 1723 fps= 26 q=1.6 size=N/A time=00:28:43.00 bitrate=N/A dup=0 drop=49858
frame= 1736 fps= 26 q=1.6 size=N/A time=00:28:56.00 bitrate=N/A dup=0 drop=50249
frame= 1749 fps= 26 q=1.6 size=N/A time=00:29:09.00 bitrate=N/A dup=0 drop=50612
frame= 1762 fps= 26 q=1.6 size=N/A time=00:29:22.00 bitrate=N/A dup=0 drop=50981
frame= 1774 fps= 26 q=1.6 size=N/A time=00:29:34.00 bitrate=N/A dup=0 drop=51349
frame= 1787 fps= 26 q=1.6 size=N/A time=00:29:47.00 bitrate=N/A dup=0 drop=51727
frame= 1800 fps= 26 q=1.6 size=N/A time=00:30:00.00 bitrate=N/A dup=0 drop=52098
frame= 1813 fps= 26 q=1.6 size=N/A time=00:30:13.00 bitrate=N/A dup=0 drop=52486
frame= 1824 fps= 26 q=1.6 Lsize=N/A time=00:30:24.00 bitrate=N/A dup=0 drop=52798
video:40987kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
The whole process took 71 seconds with a framerate of 26, CPU usage 50%.
Then I tried to run the same conversion using the same video but with 2 parallel tasks (basically converting it 2 times and saving images with 2 different names). The frame rate of each video was about 17 stable for each video, CPU usage 45 for each process, and total time was 105 seconds for the first and 104 seconds for the other. So running them one after another would have took 70+70=140 seconds, while running 2 istances at the same time, forcing the CPU to work at 100% took 105 seconds to have both videos converted, saving 35 seconds, which on large scale are importants.
Best Answer
Writing many small files is slow. That’s why the CPU isn’t at 100% load, but your hard disk probably is.
That’s of course not referring to writing at 100% possible throughput, but how fast your disk can service requests. Because creating files involves access to many regions of the disk that might be apart quite a bit, your disk’s access latency is the bottleneck here.
There is nothing you can do about this but switching to a SSD or a faster SSD. RAID0 is very unlikely to help with latency-bound loads.