[FFmpeg-user] Change frame rate without dropping/adding frames

Elliott Balsley elliottbalsley at gmail.com
Fri Jan 16 01:30:22 CET 2015 

After a long break from this issue, I have a new problem.  For
example, I want to take a 24fps video and make it play slow-mo at
12fps.  The input option -r is dropping frames, rather than slowing
down the playback speed.  I don't have my main computer right now,
which uses the latest git master; I'm just using my laptop which uses
a macports build, so maybe that's the reason?  Or am I using this
command wrong?

$ ffmpeg -r 24 -i /temp/leader.mp4 -r 12 test.mov
ffmpeg version 2.4.git-e113692 Copyright (c) 2000-2014 the FFmpeg developers
  built on Oct  4 2014 21:20:35 with Apple LLVM version 6.0
(clang-600.0.51) (based on LLVM 3.5svn)
  configuration: --prefix=/opt/local --enable-swscale
--enable-avfilter --enable-avresample --enable-libmp3lame
--enable-libvorbis --enable-libopus --enable-libtheora
--enable-libschroedinger --enable-libopenjpeg --enable-libmodplug
--enable-libvpx --enable-libspeex --enable-libass --enable-libbluray
--enable-lzma --enable-gnutls --enable-fontconfig --enable-libfreetype
--enable-libfribidi --disable-indev=jack --disable-outdev=xv
--mandir=/opt/local/share/man --enable-shared --enable-pthreads
--cc=/usr/bin/clang --enable-vda --arch=x86_64 --enable-yasm
--enable-gpl --enable-postproc --enable-libx264 --enable-libxvid
--enable-nonfree --enable-libfdk-aac --enable-libfaac
  libavutil      54.  7.101 / 54.  7.101
  libavcodec     56.  1.101 / 56.  1.101
  libavformat    56.  5.100 / 56.  5.100
  libavdevice    56.  1.100 / 56.  1.100
  libavfilter     5.  1.102 /  5.  1.102
  libavresample   2.  1.  0 /  2.  1.  0
  libswscale      3.  1.100 /  3.  1.100
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  1.100 / 53.  1.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/temp/leader.mp4':
  Metadata:
    major_brand     : M4V
    minor_version   : 1
    compatible_brands: M4V mp42isom
    creation_time   : 2015-01-16 00:15:42
  Duration: 00:00:08.09, start: 0.000000, bitrate: 2369 kb/s
    Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661),
yuv420p(tv, bt709), 1920x1080, 2181 kb/s, 23.98 fps, 23.98 tbr, 24k
tbn, 47.95 tbc (default)
    Metadata:
      creation_time   : 2015-01-16 00:15:42
      handler_name    : Mainconcept MP4 Video Media Handler
      encoder         : AVC Coding
    Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 48000 Hz,
stereo, fltp, 189 kb/s (default)
    Metadata:
      creation_time   : 2015-01-16 00:15:42
      handler_name    : Mainconcept MP4 Sound Media Handler
File 'test.mov' already exists. Overwrite ? [y/N] y
[libx264 @ 0x7fd9ab017000] using cpu capabilities: MMX2 SSE2Fast SSSE3
SSE4.2 AVX AVX2 FMA3 LZCNT BMI2
[libx264 @ 0x7fd9ab017000] profile High, level 4.0
[libx264 @ 0x7fd9ab017000] 264 - core 142 - H.264/MPEG-4 AVC codec -
Copyleft 2003-2014 - 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=12 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, mov, to 'test.mov':
  Metadata:
    major_brand     : M4V
    minor_version   : 1
    compatible_brands: M4V mp42isom
    encoder         : Lavf56.5.100
    Stream #0:0(eng): Video: h264 (libx264) (avc1 / 0x31637661),
yuv420p, 1920x1080, q=-1--1, 12 fps, 12288 tbn, 12 tbc (default)
    Metadata:
      creation_time   : 2015-01-16 00:15:42
      handler_name    : Mainconcept MP4 Video Media Handler
      encoder         : Lavc56.1.101 libx264
    Stream #0:1(eng): Audio: aac (libfaac) (mp4a / 0x6134706D), 48000
Hz, stereo, s16, 128 kb/s (default)
    Metadata:
      creation_time   : 2015-01-16 00:15:42
      handler_name    : Mainconcept MP4 Sound Media Handler
      encoder         : Lavc56.1.101 libfaac
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  Stream #0:1 -> #0:1 (aac (native) -> aac (libfaac))
Press [q] to stop, [?] for help
frame=   99 fps= 76 q=-1.0 Lsize=     335kB time=00:00:08.08 bitrate=
339.8kbits/s dup=0 drop=94
video:327kB audio:4kB subtitle:0kB other streams:0kB global
headers:0kB muxing overhead: 1.351535%
[libx264 @ 0x7fd9ab017000] frame I:2     Avg QP:20.20  size: 14859
[libx264 @ 0x7fd9ab017000] frame P:77    Avg QP:19.99  size:  3863
[libx264 @ 0x7fd9ab017000] frame B:20    Avg QP:12.33  size:   339
[libx264 @ 0x7fd9ab017000] consecutive B-frames: 72.7%  0.0%  3.0% 24.2%
[libx264 @ 0x7fd9ab017000] mb I  I16..4: 25.2% 65.1%  9.6%
[libx264 @ 0x7fd9ab017000] mb P  I16..4:  1.8%  8.8%  2.0%  P16..4:
0.6%  0.1%  0.1%  0.0%  0.0%    skip:86.6%
[libx264 @ 0x7fd9ab017000] mb B  I16..4:  0.0%  0.0%  0.1%  B16..8:
0.2%  0.0%  0.0%  direct: 0.0%  skip:99.7%  L0:55.9% L1:43.8% BI: 0.3%
[libx264 @ 0x7fd9ab017000] 8x8 transform intra:69.1% inter:18.0%
[libx264 @ 0x7fd9ab017000] coded y,uvDC,uvAC intra: 8.9% 0.0% 0.0%
inter: 0.1% 0.0% 0.0%
[libx264 @ 0x7fd9ab017000] i16 v,h,dc,p: 69% 26%  5%  0%
[libx264 @ 0x7fd9ab017000] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 49% 15% 35%
0%  0%  0%  0%  0%  0%
[libx264 @ 0x7fd9ab017000] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 33% 19% 22%
7%  4%  3%  4%  4%  4%
[libx264 @ 0x7fd9ab017000] i8c dc,h,v,p: 100%  0%  0%  0%
[libx264 @ 0x7fd9ab017000] Weighted P-Frames: Y:2.6% UV:0.0%
[libx264 @ 0x7fd9ab017000] ref P L0: 58.0%  3.9% 21.1% 15.5%  1.5%
[libx264 @ 0x7fd9ab017000] ref B L0: 96.1%  2.3%  1.6%
[libx264 @ 0x7fd9ab017000] ref B L1: 93.9%  6.1%
[libx264 @ 0x7fd9ab017000] kb/s:323.80


On 9/10/14, tim nicholson <nichot20-at-yahoo.com at ffmpeg.org> wrote:
> On 10/09/14 07:59, Carl Eugen Hoyos wrote:
>> Dave Rice <dave <at> dericed.com> writes:
>>
>>>> h264 in avi is not going to be understood
>>>> by much other than ffmpeg...
>>
>> Since this was quoted a few times, I'd like to
>> repeat that H264 in avi works fine with WMP.
>> (Contrary to any other output container that
>> would also work fine with the input option -r).
>>
>
> My original comment related more to media processors than media players,
> if all you want to do is play then fine.
>
> If someone wants to change the frame rate its usually because they want
> it at that different frame rate in order to do something further with it
> (as was the case for the original query). In those circumstances I do
> not think the original comment was inaccurate, but I apologise for not
> being precise enough.
>
> (and you could argue that only one other app falls within the "not much"
> category)
>
>
>>>[...]
>
>
> --
> Tim.
> Key Fingerprint 38CF DB09 3ED0 F607 8B67 6CED 0C0B FC44 8B0B FC83
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