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问题解决了。

tag-icon • tag-icon ffmpeg mp4 video-encoding
问题解决了。

我正在尝试使用以下命令将图像序列（frame0001.png，，frame0002.png...， ）编码为 x264 视频：frame0160.png

ffmpeg -i frame%04d.png -sameq -r 24 out.mp4

编码后，它说drop=5视频中确实有明显的“跳跃”。

似乎其他人也遇到了类似的问题，但对我来说接受的答案不是很有用，因为我不希望出现丢帧的情况。

命令中缺少开关吗？还是我做错了什么？

编辑：添加控制台输出：

ffmpeg version N-42347-g299387e Copyright (c) 2000-2012 the FFmpeg developers
  built on Jul  8 2012 15:46:39 with gcc 4.7.1
  configuration: --disable-static --enable-shared --enable-gpl --enable-version3
 --disable-w32threads --enable-runtime-cpudetect --enable-avisynth --enable-bzli
b --enable-frei0r --enable-libass --enable-libcelt --enable-libopencore-amrnb --
enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --enable-libmp3lam
e --enable-libnut --enable-libopenjpeg --enable-librtmp --enable-libschroedinger
 --enable-libspeex --enable-libtheora --enable-libutvideo --enable-libvo-aacenc
--enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --en
able-libxavs --enable-libxvid --enable-zlib
  libavutil      51. 64.100 / 51. 64.100
  libavcodec     54. 33.100 / 54. 33.100
  libavformat    54. 15.102 / 54. 15.102
  libavdevice    54.  1.100 / 54.  1.100
  libavfilter     3.  1.100 /  3.  1.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
Input #0, image2, from 'frame%04d.png':
  Duration: 00:00:06.40, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: png, rgb24, 1920x1080, 25 fps, 25 tbr, 25 tbn, 25 tbc
[graph 0 input from stream 0:0 @ 01cd1f60] w:1920 h:1080 pixfmt:rgb24 tb:1/25 fr
:25/1 sar:0/1 sws_param:flags=2
[output stream 0:0 @ 01cd2220] No opaque field provided
[auto-inserted scaler 0 @ 01cd3540] w:1920 h:1080 fmt:rgb24 sar:0/1 -> w:1920 h:
1080 fmt:yuv420p sar:0/1 flags:0x4
[libx264 @ 01cd0dc0] using cpu capabilities: MMX2 SSE2Fast SSSE3 Cache64
[libx264 @ 01cd0dc0] profile High, level 4.0
[libx264 @ 01cd0dc0] 264 - core 125 r2200 999b753 - H.264/MPEG-4 AVC codec - Cop
yleft 2003-2012 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deb
lock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 m
e_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chro
ma_qp_offset=-2 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 i
nterlaced=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=24 scenec
ut=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 'out.mp4':
  Metadata:
    encoder         : Lavf54.15.102
    Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 1920x1080, q=-1-
-1, 24 tbn, 24 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (png -> libx264)
Press [q] to stop, [?] for help
frame=    8 fps=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=   0.0kbits/s
frame=   15 fps= 15 q=0.0 size=       0kB time=00:00:00.00 bitrate=   0.0kbits/s
frame=   22 fps= 14 q=0.0 size=       0kB time=00:00:00.00 bitrate=   0.0kbits/s
frame=   29 fps= 14 q=0.0 size=       0kB time=00:00:00.00 bitrate=   0.0kbits/s
frame=   36 fps= 14 q=0.0 size=       0kB time=00:00:00.00 bitrate=   0.0kbits/s
frame=   43 fps= 14 q=0.0 size=       0kB time=00:00:00.00 bitrate=   0.0kbits/s
frame=   47 fps= 11 q=0.0 size=       0kB time=00:00:00.00 bitrate=   0.0kbits/s
frame=   53 fps= 11 q=28.0 size=     111kB time=00:00:00.04 bitrate=21735.2kbits
frame=   59 fps= 11 q=28.0 size=     268kB time=00:00:00.29 bitrate=7527.8kbits/
frame=   63 fps= 10 q=28.0 size=     375kB time=00:00:00.45 bitrate=6708.1kbits/
frame=   69 fps= 10 q=28.0 size=     538kB time=00:00:00.70 bitrate=6219.6kbits/
frame=   74 fps= 10 q=28.0 size=     675kB time=00:00:00.91 bitrate=6032.7kbits/
frame=   79 fps= 10 q=28.0 size=     802kB time=00:00:01.12 bitrate=5840.7kbits/
frame=   84 fps= 10 q=28.0 size=     922kB time=00:00:01.33 bitrate=5662.9kbits/
frame=   89 fps=9.9 q=28.0 size=    1060kB time=00:00:01.54 bitrate=5633.3kbits/
frame=   94 fps=9.9 q=28.0 size=    1186kB time=00:00:01.75 bitrate=5551.2kbits/
frame=   98 fps=9.7 q=28.0 size=    1309kB time=00:00:01.91 bitrate=5594.3kbits/
frame=  103 fps=9.7 q=28.0 size=    1436kB time=00:00:02.12 bitrate=5536.4kbits/
frame=  107 fps=9.6 q=28.0 size=    1533kB time=00:00:02.29 bitrate=5481.7kbits/
frame=  112 fps=9.5 q=28.0 size=    1654kB time=00:00:02.50 bitrate=5421.3kbits/
frame=  117 fps=9.4 q=28.0 size=    1781kB time=00:00:02.70 bitrate=5386.9kbits/
frame=  123 fps=9.4 q=28.0 size=    1925kB time=00:00:02.95 bitrate=5331.5kbits/
frame=  128 fps=9.4 q=28.0 size=    2030kB time=00:00:03.16 bitrate=5250.8kbits/
frame=  133 fps=9.4 q=28.0 size=    2210kB time=00:00:03.37 bitrate=5363.8kbits/
frame=  138 fps=9.3 q=28.0 size=    2356kB time=00:00:03.58 bitrate=5386.0kbits/
frame=  142 fps=9.3 q=28.0 size=    2465kB time=00:00:03.75 bitrate=5384.3kbits/
frame=  147 fps=9.3 q=28.0 size=    2602kB time=00:00:03.95 bitrate=5385.0kbits/
frame=  151 fps=9.2 q=28.0 size=    2706kB time=00:00:04.12 bitrate=5374.3kbits/
frame=  155 fps=9.2 q=28.0 size=    2812kB time=00:00:04.29 bitrate=5367.7kbits/
frame=  155 fps=7.0 q=28.0 Lsize=    4129kB time=00:00:06.37 bitrate=5306.4kbits
/s dup=0 drop=5
video:4128kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.035320%
[libx264 @ 01cd0dc0] frame I:2     Avg QP:21.97  size: 79850
[libx264 @ 01cd0dc0] frame P:153   Avg QP:23.43  size: 26579
[libx264 @ 01cd0dc0] mb I  I16..4:  9.6% 70.5% 19.9%
[libx264 @ 01cd0dc0] mb P  I16..4:  7.0% 15.3%  0.7%  P16..4: 45.2%  9.1%  2.2%
 0.0%  0.0%    skip:20.5%
[libx264 @ 01cd0dc0] 8x8 transform intra:66.7% inter:85.7%
[libx264 @ 01cd0dc0] coded y,uvDC,uvAC intra: 38.6% 58.0% 6.0% inter: 16.2% 27.2
% 0.2%
[libx264 @ 01cd0dc0] i16 v,h,dc,p: 35% 29% 17% 19%
[libx264 @ 01cd0dc0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 26% 21% 31%  3%  4%  5%  4%
 4%  3%
[libx264 @ 01cd0dc0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 29% 19% 13%  5%  8%  9%  7%
 6%  4%
[libx264 @ 01cd0dc0] i8c dc,h,v,p: 49% 23% 23%  5%
[libx264 @ 01cd0dc0] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 01cd0dc0] ref P L0: 84.5% 10.9%  3.5%  1.1%
[libx264 @ 01cd0dc0] kb/s:5235.14

答案1

问题解决了。

通过查看控制台输出，似乎输入序列的默认帧速率为 25 fps：

Input #0, image2, from 'frame%04d.png':
  Duration: 00:00:06.40, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: png, rgb24, 1920x1080, 25 fps, 25 tbr, 25 tbn, 25 tbc

来自文档：

强制将输入文件的帧速率（仅对原始格式有效）设置为 1 fps，并将输出文件的帧速率设置为 24 fps：

ffmpeg -r 1 -i input.m2v -r 24 output.avi

因此，我需要做的只是添加另一个-r 24：

ffmpeg-r 24-i frame%04d.png -r 24 out.mp4

答案2

丢帧的另一个原因是 .png 的格式不同。例如，通过 ImageMagickconvert命令创建的 .png 通常是“颜色 RGB”，但颜色少于 256 种的 .png 会被默默优化为“颜色图”或调色板，以减小文件大小。当 ffmpeg 遇到从一个格式到另一个格式的更改时，它会开始丢帧：

Input stream #0:0 frame changed from size:1280x720 fmt:rgb24 to size:1280x720 fmt:pal8
Input stream #0:0 frame changed from size:1280x720 fmt:pal8 to size:1280x720 fmt:rgb24

为了避免丢失此类帧，convert -define png:color-type=2。

答案3

另一个答案是错误的，正确的命令是：

ffmpeg -framerate 24 -i frame%04d.png out.mp4

-framerate 选项特定于 image2“图像序列”输入，指定图像序列的原始帧速率。请参阅：https://www.ffmpeg.org/ffmpeg-formats.html#image2-1

此选项应放置在图像序列输入之前，以应用于该输入。以正确的方式指定帧速率还可确保某些视频过滤器按预期工作。

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