Issue with latest FFmpeg and auto_alt_ref argument

[altbdoor]

I am on Windows 10, and am using the current latest static Windows build from Zeranoe (20170117-f7e9275). Recording was successful, but an error occurs during the FFmpeg process.

Input #0, image2, from '%d.png':
  Duration: 00:00:01.23, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: png, rgba(pc), 479x393 [SAR 4724:4724 DAR 479:393], 30 fps, 30 tbr, 30 tbn, 30 tbc
[libvpx @ 0000000000778560] v1.6.0
[libvpx @ 0000000000778560] Transparency encoding with auto_alt_ref does not work
Stream mapping:
  Stream #0:0 -> #0:0 (png (native) -> vp8 (libvpx))
Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

I googled a little bit and stumbled on a StackOverflow question. It appears that the error message on auto_alt_ref is significant enough, and needs to disabled via -auto-alt-ref 0. After including it into my FFmpeg arguments, FFmpeg was able to process the WebM.

I do not know what auto_alt_ref does, and the wiki only states:

-auto-alt-ref Enable use of alternate reference frames (2-pass only) (0 disabled, 1 enabled <default 0>)

It looks like its enabled in the new builds? Should WebMCam include this argument by default?

[michaelmob]

Absolutely. I'll fix this today. Great work!

[slx7R4GDZM]

I'm still having this issue on Windows 10 with 2.4.0.

ffmpeg version N-83152-gf7e9275 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 5.4.0 (GCC)
  configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-decklink --enable-zlib
  libavutil      55. 43.100 / 55. 43.100
  libavcodec     57. 74.100 / 57. 74.100
  libavformat    57. 62.100 / 57. 62.100
  libavdevice    57.  2.100 / 57.  2.100
  libavfilter     6. 69.100 /  6. 69.100
  libswscale      4.  3.101 /  4.  3.101
  libswresample   2.  4.100 /  2.  4.100
  libpostproc    54.  2.100 / 54.  2.100
Input #0, image2, from '%d.png':
  Duration: 00:00:00.42, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: png, rgba(pc), 359x319 [SAR 3779:3779 DAR 359:319], 60 fps, 60 tbr, 60 tbn, 60 tbc
[libvpx @ 00000000025d44a0] v1.6.0
[libvpx @ 00000000025d44a0] Transparency encoding with auto_alt_ref does not work
Stream mapping:
  Stream #0:0 -> #0:0 (png (native) -> vp8 (libvpx))
Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

[altbdoor]

@slx7R4GDZM under Options > FFmpeg Arguments, is -auto-alt-ref 0 present? As an example, this is the default FFmpeg Arguments content, which can be found when you Reset Arguments:

-framerate {fps:avg} -i {format} {audio} -c:v {codec} -auto-alt-ref 0 -b:v 2M -r {fps:avg} {output}

If its not there, try copy/pasting the argument into the FFmpeg Arguments field, and attempt to record again.

[slx7R4GDZM]

@slx7R4GDZM under Options > FFmpeg Arguments, is -auto-alt-ref 0 present?

It wasn't. Thanks, that fixed it.