FFMPEG for animation of image files outputs all-black video

Question

I am trying to create an animation of a few images ("f_01.png", "f_02.png", ..., "f_08.png") that are each a different solid colour, but it always outputs a video entirely made up of black frames.

What, exactly, do I need to enter to get this to work? (again: images "f_01.png", "f_02.png", ..., "f_08.png")

---

More background:

I have read some questions on SuperUser about creating videos from images (and am trying to follow this: https://superuser.com/a/318412/219755 ...and this: https://superuser.com/a/53778/219755 ...and another answer I cannot track down again), I have read the FFMPEG help section on creating videos from image files (here: http://ffmpeg.org/faq.html#How-do-I-encode-single-pictures-into-movies_003f), and I have tried various sample command line strings from around the internet, but I cannot get FFMPEG to output anything but an all-black video.

In case it matters, I am playing the videos back with VLC.

The videos are the right length, at least most of the time (I am choosing 1 FPS and most videos output are the correct 8 seconds in length), but I don't see any of what I should be seeing.

Originally the first frame was black, and I thought FFMPEG ignoring other images might be the problem, but I have tried forcing all frames to be keyframes (with -g 1, with -keyint_min 1, and with both), and I have tried making a white image the first frame, but I still got black output videos.

Here are some strings I have tried entering:

ffmpeg -r 1 -i f_%02d.png output.mp4
ffmpeg -r 1 -f image2 -i f_%02d.png output.mp4
ffmpeg -r 1 -f image2 -i f_%02d.png -g 1 -keyint_min 1 output.mp4

In case it matters, the first two commands give me a video where playback time is only 6 seconds, but the third gives me an 8-second video.

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As requested, the output from the 1st command is:

G:\FFMPEG>ffmpeg -r 1 -i f_%02d.png output.mp4
ffmpeg version N-55515-gbbbd959 Copyright (c) 2000-2013 the FFmpeg developers
  built on Aug 13 2013 18:01:31 with gcc 4.7.3 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
le-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetyp
e --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --ena
ble-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-l
ibopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libsp
eex --enable-libtheora --enable-libtwolame --enable-libvo-aacenc --enable-libvo-
amrwbenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --
enable-libxvid --enable-zlib
  libavutil      52. 42.100 / 52. 42.100
  libavcodec     55. 27.100 / 55. 27.100
  libavformat    55. 13.102 / 55. 13.102
  libavdevice    55.  3.100 / 55.  3.100
  libavfilter     3. 82.100 /  3. 82.100
  libswscale      2.  4.100 /  2.  4.100
  libswresample   0. 17.103 /  0. 17.103
  libpostproc    52.  3.100 / 52.  3.100
Input #0, image2, from 'f_%02d.png':
  Duration: 00:00:00.36, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: png, rgb24, 320x240 [SAR 3779:3779 DAR 4:3], 25 fps, 25
tbr, 25 tbn, 25 tbc
File 'output.mp4' already exists. Overwrite ? [y/N] y
No pixel format specified, yuv444p for H.264 encoding chosen.
Use -pix_fmt yuv420p for compatibility with outdated media players.
[libx264 @ 003ff8e0] using SAR=1/1
[libx264 @ 003ff8e0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 @ 003ff8e0] profile High 4:4:4 Predictive, level 1.2, 4:4:4 8-bit
[libx264 @ 003ff8e0] 264 - core 135 r2345 f0c1c53 - H.264/MPEG-4 AVC codec - Cop
yleft 2003-2013 - 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=4 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 in
terlaced=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=1 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 'output.mp4':
  Metadata:
    encoder         : Lavf55.13.102
    Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv444p, 320x24
0 [SAR 1:1 DAR 4:3], q=-1--1, 16384 tbn, 1 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (png -> libx264)
Press [q] to stop, [?] for help
frame=    9 fps=0.0 q=-1.0 Lsize=       2kB time=00:00:07.00 bitrate=   2.3kbits
/s
video:1kB audio:0kB subtitle:0 global headers:0kB muxing overhead 82.314815%
[libx264 @ 003ff8e0] frame I:1     Avg QP: 2.00  size:    91
[libx264 @ 003ff8e0] frame P:5     Avg QP: 1.00  size:    42
[libx264 @ 003ff8e0] frame B:3     Avg QP: 2.00  size:    18
[libx264 @ 003ff8e0] consecutive B-frames: 33.3% 66.7%  0.0%  0.0%
[libx264 @ 003ff8e0] mb I  I16..4: 100.0%  0.0%  0.0%
[libx264 @ 003ff8e0] mb P  I16..4: 19.9%  0.1%  0.0%  P16..4:  0.0%  0.0%  0.0%
 0.0%  0.0%    skip:80.0%
[libx264 @ 003ff8e0] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8:  0.3%  0.0%  0.0%
 direct: 0.0%  skip:99.7%  L0: 0.0% L1:100.0% BI: 0.0%
[libx264 @ 003ff8e0] 8x8 transform intra:0.2%
[libx264 @ 003ff8e0] coded y,u,v intra: 0.0% 0.0% 0.0% inter: 0.0% 0.0% 0.0%
[libx264 @ 003ff8e0] i16 v,h,dc,p: 93%  0%  7%  0%
[libx264 @ 003ff8e0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu:  0%  0% 100%  0%  0%  0%  0%
  0%  0%
[libx264 @ 003ff8e0] Weighted P-Frames: Y:80.0% UV:0.0%
[libx264 @ 003ff8e0] kb/s:0.31

G:\FFMPEG>

As requested, the original image files:

f_01.png and f_02.png (same image twice)
f_03.png and f_04.png (same image twice)
f_05.png and f_06.png (same image twice)
f_07.png and f_08.png (same image twice)

Answer 1

The videos generated with your files and the following commands both play fine for me in ffplay. The one with yuv420p chosen as the pixel format also plays fine in QuickTime.

ffmpeg -r 1 -i f_%02d.png out.mp4
ffmpeg -r 1 -i f_%02d.png -pix_fmt yuv420p out.mp4

Only VLC has troubles displaying the video (download). It'll show me a second of grey and then black, but not for a duration of 8 seconds.*

To produce stable video, you can try to increase the output frame rate, since it's the 1 fps that most players will choke on. The output file will be bigger than needed, of course.

ffmpeg -r 1 -i f_%02d.png -r 25 out.mp4
ffmpeg -r 1 -i f_%02d.png -pix_fmt yuv420p -r 25 out.mp4         <= for older players

Here we've told to read the images at 1 frame per second, but output them (duplicating frames) at 25.

_{* I consider this a bug with VLC. Since it's based on libavcodec and libavformat (from the FFmpeg project), and ffplay handles the file just fine, VLC should have no major issues with it. I would suggest you create a bug report in VLC – chances are the file isn't parsed correctly.}