【发布时间】：2018-06-21 14:53:18
【问题描述】：
我正在尝试将视频从 607x1080 缩小到 440 宽度，并使用以下命令自动计算高度。它会缩放视频，但不会缩放到指定的尺寸。即使下面的输出显示为 440x384，视频也会缩放到 216x384。
ffmpeg -i video.mp4 -vf scale=440:-2 -c:v libx264 -c:a aac -y video-out.mp4
输出如下：
ffmpeg version N-87043-gf0f48884b0-static http://johnvansickle.com/ffmpeg/ Copyright (c) 2000-2017 the FFmpeg developers
built with gcc 6.4.0 (Debian 6.4.0-2) 20170724
configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc-6 --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gray --enable-libfribidi --enable-libass --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-librtmp --enable-libsoxr --enable-libspeex --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libzimg
libavutil 55. 74.100 / 55. 74.100
libavcodec 57.103.100 / 57.103.100
libavformat 57. 77.100 / 57. 77.100
libavdevice 57. 7.101 / 57. 7.101
libavfilter 6.100.100 / 6.100.100
libswscale 4. 7.103 / 4. 7.103
libswresample 2. 8.100 / 2. 8.100
libpostproc 54. 6.100 / 54. 6.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video.mp4':
Metadata:
major_brand : mp42
minor_version : 512
compatible_brands: isomiso2avc1mp41
creation_time : 2017-12-13T19:49:15.000000Z
encoder : HandBrake 1.0.7 2017040900
Duration: 00:00:04.37, start: 0.000000, bitrate: 10080 kb/s
Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709), 1238x1080 [SAR 27:55 DAR 619:1100], 10244 kb/s, 30 fps, 30 tbr, 90k tbn, 180k tbc (default)
Metadata:
creation_time : 2017-12-13T19:49:15.000000Z
handler_name : VideoHandler
Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 2 kb/s (default)
Metadata:
creation_time : 2017-12-13T19:49:15.000000Z
handler_name : Stereo
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
[libx264 @ 0x5aef920] using SAR=1215/2474
[libx264 @ 0x5aef920] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 @ 0x5aef920] profile High, level 2.2
[libx264 @ 0x5aef920] 264 - core 152 r19 ba24899 - 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=12 lookahead_threads=2 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 'video-out.mp4':
Metadata:
major_brand : mp42
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf57.77.100
Stream #0:0(und): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 440x384 [SAR 7428:15125 DAR 619:1100], q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
Metadata:
creation_time : 2017-12-13T19:49:15.000000Z
handler_name : VideoHandler
encoder : Lavc57.103.100 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
creation_time : 2017-12-13T19:49:15.000000Z
handler_name : Stereo
encoder : Lavc57.103.100 aac
frame= 121 fps=0.0 q=29.0 size= 0kB time=00:00:04.33 bitrate= 0.1kbits/s speed=8.65x
frame= 129 fps=0.0 q=-1.0 Lsize= 255kB time=00:00:04.37 bitrate= 478.0kbits/s speed=6.81x
video:248kB audio:1kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 2.344491%
[libx264 @ 0x5aef920] frame I:1 Avg QP:22.07 size: 5065
[libx264 @ 0x5aef920] frame P:52 Avg QP:23.68 size: 4248
[libx264 @ 0x5aef920] frame B:76 Avg QP:24.30 size: 361
[libx264 @ 0x5aef920] consecutive B-frames: 12.4% 20.2% 20.9% 46.5%
[libx264 @ 0x5aef920] mb I I16..4: 13.1% 81.7% 5.2%
[libx264 @ 0x5aef920] mb P I16..4: 2.1% 5.2% 1.5% P16..4: 36.4% 12.2% 8.2% 0.0% 0.0% skip:34.4%
[libx264 @ 0x5aef920] mb B I16..4: 0.2% 0.2% 0.1% B16..8: 16.3% 1.3% 0.2% direct: 0.5% skip:81.2% L0:42.2% L1:52.1% BI: 5.8%
[libx264 @ 0x5aef920] 8x8 transform intra:62.0% inter:70.3%
[libx264 @ 0x5aef920] coded y,uvDC,uvAC intra: 52.3% 45.2% 20.0% inter: 13.3% 10.0% 2.6%
[libx264 @ 0x5aef920] i16 v,h,dc,p: 17% 48% 11% 24%
[libx264 @ 0x5aef920] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 8% 35% 23% 5% 3% 2% 6% 3% 14%
[libx264 @ 0x5aef920] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 8% 29% 16% 6% 7% 4% 12% 4% 14%
[libx264 @ 0x5aef920] i8c dc,h,v,p: 64% 26% 7% 2%
[libx264 @ 0x5aef920] Weighted P-Frames: Y:32.7% UV:5.8%
[libx264 @ 0x5aef920] ref P L0: 55.7% 22.1% 15.8% 5.8% 0.7%
[libx264 @ 0x5aef920] ref B L0: 77.8% 15.9% 6.3%
[libx264 @ 0x5aef920] ref B L1: 97.6% 2.4%
[libx264 @ 0x5aef920] kb/s:471.40
[aac @ 0x5b7e180] Qavg: 65536.000
我进行了一些搜索并了解到这可能是使用 libx264 编解码器进行缩放并且输入宽度为奇数的问题？如果是这样，是否有解决方法让视频缩放到指定大小？谢谢。
【问题讨论】：
标签： ffmpeg