[FFmpeg-user] Unable to encode web with frame rates <1 fps

[Johnny Klonaris]

Hi all…

I'm trying to create videos with small fps values in both mp4 (libx264) and webm (libvpx)
formats.   I"m OK down to 1 fps, but anything less only works with libx264  - if I try to use libvpx, 
I get an error:

Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate,
rate, width or height

If the frame rate is  >-= 1,  or if I only use libx264, no problem.   I'm specifying sub-second
frame rates as a fraction (e.g. 1/10), but I've also tried decimals:  "0.1".

The runstring looks like this:

/usr/local/bin/ffmpeg 	-y -r 1/10 -i  .../Overlays/Frame-%05d.png   -i ".../audio.aif"  \
  -codec:v libvpx  -b:v 500k -codec:a libvorbis -qscale:a 5 -threads 3 -r 1/10 ".../QuickTest-media.web" \
  -codec:v libx264 -profile:v baseline -movflags faststart -pix_fmt yuv420p -threads 3 -codec:a aac \
  -strict -2 -r 1/10 ".../QuickTest-media.mp4"

I've used various versions of ffmpeg - most recently 2.1.1:

$ /usr/local/bin/ffmpeg -version
ffmpeg version 2.1.1
built on Nov 23 2013 13:37:12 with llvm-gcc 4.2.1 (LLVM build 2336.11.00)
configuration: --enable-libx264 --enable-gpl --enable-libvpx --enable-libtheora --enable-libvorbis
libavutil      52. 48.101 / 52. 48.101
libavcodec     55. 39.101 / 55. 39.101
libavformat    55. 19.104 / 55. 19.104
libavdevice    55.  5.100 / 55.  5.100
libavfilter     3. 90.100 /  3. 90.100
libswscale      2.  5.101 /  2.  5.101
libswresample   0. 17.104 /  0. 17.104
libpostproc    52.  3.100 / 52.  3.100

My libvpx is 1.1.0.

I'm on a Mac running OSX v10.8.5

I've installed with homebrew, pulling from git (that failed last time), and most recently
configured and made from source.

I've seen various hints online saying this should work - I just can't figure out what part I"m getting wrong.

I've tried encoding separately - but no difference: libx264 is ok, libvpx throws an error.

Full output from my run:

ffmpeg version 2.1.1 Copyright (c) 2000-2013 the FFmpeg developers
  built on Nov 23 2013 13:37:12 with llvm-gcc 4.2.1 (LLVM build 2336.11.00)
  configuration: --enable-libx264 --enable-gpl --enable-libvpx --enable-libtheora --enable-libvorbis
  libavutil      52. 48.101 / 52. 48.101
  libavcodec     55. 39.101 / 55. 39.101
  libavformat    55. 19.104 / 55. 19.104
  libavdevice    55.  5.100 / 55.  5.100
  libavfilter     3. 90.100 /  3. 90.100
  libswscale      2.  5.101 /  2.  5.101
  libswresample   0. 17.104 /  0. 17.104
  libpostproc    52.  3.100 / 52.  3.100
Input #0, image2, from '/Users/Johnny/dev/coLab/Group/Johnny/Page/QuickTest1/coLab_local/Overlays/Frame-%05d.png':
  Duration: 00:00:37.08, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: png, rgba, 160x120, 25 fps, 25 tbr, 25 tbn, 25 tbc
Guessed Channel Layout for  Input Stream #1.0 : stereo
Input #1, aiff, from '/Users/Johnny/dev/coLab/Group/Johnny/Page/QuickTest1/coLab_local/Nuggets1.aif':
  Metadata:
    comment         : 
  Duration: 00:15:27.62, start: 0.000000, bitrate: 1411 kb/s
    Stream #1:0: Audio: pcm_s16be, 44100 Hz, stereo, s16, 1411 kb/s
[libvpx @ 0x7fb9d8861a00] v1.1.0
[libvpx @ 0x7fb9d8861a00] Failed to initialize encoder: Invalid parameter
[libvpx @ 0x7fb9d8861a00]   Additional information: g_timebase.num out of range [1..cfg->g_timebase.den]
Output #0, webm, to '/Users/Johnny/dev/coLab/Group/Johnny/Page/QuickTest1/QuickTest1-media.webm':
    Stream #0:0: Video: vp8, yuva420p, 160x120, q=-1--1, 500 kb/s, 90k tbn, 0.10 tbc
    Stream #0:1: Audio: vorbis, 44100 Hz, stereo, fltp
Output #1, mp4, to '/Users/Johnny/dev/coLab/Group/Johnny/Page/QuickTest1/QuickTest1-media.mp4':
    Stream #1:0: Video: h264, yuv420p, 160x120, q=-1--1, 90k tbn, 0.10 tbc
    Stream #1:1: Audio: aac, 44100 Hz, stereo, fltp, 128 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (png -> libvpx)
  Stream #1:0 -> #0:1 (pcm_s16be -> libvorbis)
  Stream #0:0 -> #1:0 (png -> libx264)
  Stream #1:0 -> #1:1 (pcm_s16be -> aac)
Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

If there's any more I should post - please let me know.

--

Thanks in advance for any hints.

-Johnny