I tried it and got the following output. Btw, I see t3g's post; I might give
that a try too after I learn how to add a ppa.
avconv version 9.16-6:9.16-0ubuntu0.14.04.1, Copyright (c) 2000-2014 the
Libav developers
built on Aug 10 2014 18:16:02 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
[matroska,webm @ 0x2373920] Unknown/unsupported AVCodecID V_VP9.
[matroska,webm @ 0x2373920] max_analyze_duration reached
Input #0, matroska,webm, from '/home/user/plenary-v.webm':
Duration: 00:47:10.12, start: 0.000000, bitrate: N/A
Stream #0.0(eng): Video: [0][0][0][0] / 0x0000, 1280x720, PAR 1:1 DAR
16:9, 25 fps, 25 tbr, 1k tbn (default)
Input #1, matroska,webm, from '/home/user/plenary-a.webm':
Duration: 00:47:10.15, start: 0.000000, bitrate: N/A
Stream #1.0(eng): Audio: vorbis, 44100 Hz, stereo, fltp (default)
[webm @ 0x238a2a0] Only VP8 video and Vorbis audio are supported for WebM.
Output #0, webm, to '/home/user/plenary-av.webm':
Metadata:
encoder : Lavf54.20.4
Stream #0.0(eng): Video: [0][0][0][0] / 0x0000, 1280x720 [PAR 1:1 DAR
16:9], q=2-31, 90k tbn, 1k tbc (default)
Stream #0.1(eng): Audio: libvorbis, 44100 Hz, stereo (default)
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #1:0 -> #0:1 (copy)
Could not write header for output file #0 (incorrect codec parameters ?):
Invalid argument
