ffmpeg is preferring to encode in VP9 but I'm trying to encode in VP8

Question

I'm trying to encode webm video files specifically in VP8, but ffmpeg is forcing VP9. I'm using -c:v libvpx, which to my knowledge is supposed to be VP8, but when it encodes I see it's encoding in VP9 instead:

ffmpeg -framerate 7 -loop 1 -i "C:\converted\cover.jpg" -c:v libvpx
-i "C:\converted\Image.wav" -b:v 50k -c:a libvorbis -b:a 96k
-vf scale=-1:300 -shortest -metadata title="%artist% - %album%" 
-metadata author="%artist%" -threads 8 -y "C:\converted\%artist% - %album%.webm"

ffmpeg version N-81489-ga37e6dd Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 5.4.0 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-dx
va2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-lib
ebur128 --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --ena
ble-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfree
type --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enab
le-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-lib
openh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschr
oedinger --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheor
a --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvo
rbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --ena
ble-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --e
nable-decklink --enable-zlib
  libavutil      55. 29.100 / 55. 29.100
  libavcodec     57. 54.101 / 57. 54.101
  libavformat    57. 48.101 / 57. 48.101
  libavdevice    57.  0.102 / 57.  0.102
  libavfilter     6. 57.100 /  6. 57.100
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  1.100 /  2.  1.100
  libpostproc    54.  0.100 / 54.  0.100
Input #0, image2, from 'C:\converted\cover.jpg':
  Duration: 00:00:00.14, start: 0.000000, bitrate: 3159 kb/s
    Stream #0:0: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 500x495 [S
AR 1:1 DAR 100:99], 7 fps, 7 tbr, 7 tbn, 7 tbc
Guessed Channel Layout for Input Stream #1.0 : stereo
Input #1, wav, from 'C:\converted\Image.wav':
  Metadata:
    artist          : ???????
    genre           : Alternative Rock
    title           : goodnight, wonderend
    date            : 2014
  Duration: 00:04:48.00, bitrate: 1421 kb/s
    Stream #1:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, 2 channels,
 s16, 1411 kb/s
[swscaler @ 055f7d60] deprecated pixel format used, make sure you did set range
correctly
[libvpx-vp9 @ 0312d8e0] v1.6.0
[webm @ 0316e380] Using AVStream.codec to pass codec parameters to muxers is dep
recated, use AVStream.codecpar instead.
    Last message repeated 1 times
Output #0, webm, to 'C:\converted\カラスヤサボウ - goodnight, wonderend.w
ebm':
  Metadata:
    title           : カラスヤサボウ - goodnight, wonderend
    author          : カラスヤサボウ
    encoder         : Lavf57.48.101
    Stream #0:0: Video: vp9 (libvpx-vp9), yuv420p, 303x300 [SAR 10000:9999 DAR 1
00:99], q=-1--1, 50 kb/s, 7 fps, 1k tbn, 7 tbc
    Metadata:
      encoder         : Lavc57.54.101 libvpx-vp9
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
    Stream #0:1: Audio: vorbis (libvorbis), 44100 Hz, stereo, fltp, 96 kb/s
    Metadata:
      encoder         : Lavc57.54.101 libvorbis
Stream mapping:
  Stream #0:0 -> #0:0 (mjpeg (native) -> vp9 (libvpx-vp9))
  Stream #1:0 -> #0:1 (pcm_s16le (native) -> vorbis (libvorbis))
Press [q] to stop, [?] for help
frame=   30 fps=0.0 q=0.0 size=      29kB time=00:00:00.71 bitrate= 333.4kbits/s
frame=   37 fps= 36 q=0.0 size=      49kB time=00:00:01.71 bitrate= 233.6kbits/s
frame=   45 fps= 27 q=0.0 size=      60kB time=00:00:02.85 bitrate= 170.6kbits/s
frame=   53 fps= 23 q=0.0 size=      84kB time=00:00:04.00 bitrate= 172.7kbits/s
frame=   57 fps= 21 q=0.0 size=     102kB time=00:00:04.57 bitrate= 183.5kbits/s
frame=   62 fps= 19 q=0.0 size=     112kB time=00:00:05.28 bitrate= 173.4kbits/s
frame=   64 fps= 12 q=0.0 Lsize=     141kB time=00:00:09.00 bitrate= 128.1kbits/
s speed=1.69x
video:87kB audio:47kB subtitle:0kB other streams:0kB global headers:4kB muxing o
verhead: 4.908199%
Exiting normally, received signal 2.

The build I have does have --enable-libvpx and --enable-libvpx-vp9 flags. It is also the latest default static build, I made no changes, just extracted it: ffmpeg-20160828-a37e6dd-win32-static.zip

I was using an outdated build for a long time and updated today. I can't find any documentation online to help me with this problem.

Answer 1

You should place the codec option right before your output.

Following is a simple example

$ ffmpeg -f lavfi -i testsrc2=d=5 -vcodec libvpx -f lavfi -i sine=d=5 -acodec libvorbis o.webm

The command above only select the -acodec as libvorbis, and use the default video codec.

The command below will select video codec as libvpx and audio codec as libvorbis

$ ffmpeg -f lavfi -i testsrc2=d=5 -f lavfi -i sine=d=5 -vcodec libvpx -acodec libvorbis o.webm

Answer 2

Option placement matters. You're attempting to apply -c:v libvpx to Image.wav. Move this option so it is before the output name.