ffmpeg -loop 1 -f image2 -i bg.png -r 25 -vframes 2500 -vcodec libvpx -b 1500k -vf "movie=mercury.flv [logo]; [in][logo] overlay=0:0 [out]" -y -acodec libvorbis filename.webm
ffmpeg version 1.2.1 Copyright (c) 2000-2013 the FFmpeg developers
  built on Jun 21 2013 12:33:57 with gcc 4.8.1 (GCC) 20130603 (Red Hat 4.8.1-1)
  configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --optflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic' --enable-bzlib --disable-crystalhd --enable-frei0r --enable-gnutls --enable-libass --enable-libcelt --enable-libdc1394 --disable-indev=jack --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-openal --enable-libopencv --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libv4l2 --enable-libvpx --enable-libx264 --enable-libxvid --enable-x11grab --enable-avfilter --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-runtime-cpudetect
  libavutil      52. 18.100 / 52. 18.100
  libavcodec     54. 92.100 / 54. 92.100
  libavformat    54. 63.104 / 54. 63.104
  libavdevice    54.  3.103 / 54.  3.103
  libavfilter     3. 42.103 /  3. 42.103
  libswscale      2.  2.100 /  2.  2.100
  libswresample   0. 17.102 /  0. 17.102
  libpostproc    52.  2.100 / 52.  2.100
[image2 @ 0x20db7e0] max_analyze_duration 5000000 reached at 5000000 microseconds
Input #0, image2, from 'bg.png':
  Duration: 00:00:00.04, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: png, rgb24, 533x300 [SAR 2835:2835 DAR 533:300], 25 fps, 25 tbr, 25 tbn, 25 tbc
Please use -b:a or -b:v, -b is ambiguous
[Parsed_overlay_1 @ 0x2326ce0] Overlay area with coordinates x1:0 y1:0 x2:544 y2:304 is not completely contained within the output with size 533x300
[libvpx @ 0x20cdf60] v1.2.0
Output #0, webm, to 'filename.webm':
  Metadata:
    encoder         : Lavf54.63.104
    Stream #0:0: Video: vp8, yuv420p, 533x300 [SAR 1:1 DAR 533:300], q=-1--1, 1500 kb/s, 1k tbn, 25 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (png -> libvpx)
Press [q] to stop, [?] for help
frame=   27 fps=0.0 q=0.0 size=      96kB time=00:00:01.08 bitrate= 731.5kbits/sframe=   53 fps= 52 q=0.0 size=     224kB time=00:00:02.12 bitrate= 867.2kbits/sframe=   80 fps= 53 q=0.0 size=     384kB time=00:00:03.20 bitrate= 984.1kbits/sframe=  103 fps= 51 q=0.0 size=     512kB time=00:00:04.12 bitrate=1018.9kbits/sframe=  127 fps= 50 q=0.0 size=     648kB time=00:00:05.08 bitrate=1045.6kbits/sframe=  154 fps= 50 q=0.0 size=     752kB time=00:00:06.16 bitrate= 999.8kbits/sframe=  178 fps= 50 q=0.0 size=     880kB time=00:00:07.12 bitrate=1012.3kbits/sframe=  205 fps= 50 q=0.0 size=    1008kB time=00:00:08.20 bitrate=1006.8kbits/sframe=  231 fps= 50 q=0.0 size=    1136kB time=00:00:09.24 bitrate=1007.0kbits/sframe=  255 fps= 50 q=0.0 size=    1281kB time=00:00:10.20 bitrate=1028.9kbits/sframe=  280 fps= 50 q=0.0 size=    1422kB time=00:00:11.20 bitrate=1040.0kbits/sframe=  310 fps= 51 q=0.0 size=    1550kB time=00:00:12.40 bitrate=1023.9kbits/sframe=  333 fps= 50 q=0.0 size=    1678kB time=00:00:13.32 bitrate=1031.9kbits/sframe=  357 fps= 50 q=0.0 size=    1806kB time=00:00:14.28 bitrate=1036.0kbits/sframe=  383 fps= 50 q=0.0 size=    1959kB time=00:00:15.32 bitrate=1047.4kbits/sframe=  406 fps= 50 q=0.0 size=    2068kB time=00:00:16.24 bitrate=1043.1kbits/sframe=  430 fps= 49 q=0.0 size=    2196kB time=00:00:17.20 bitrate=1045.9kbits/sframe=  452 fps= 49 q=0.0 size=    2356kB time=00:00:18.08 bitrate=1067.5kbits/sframe=  476 fps= 49 q=0.0 size=    2484kB time=00:00:19.04 bitrate=1068.7kbits/sframe=  501 fps= 49 q=0.0 size=    2612kB time=00:00:20.04 bitrate=1067.7kbits/sframe=  524 fps= 49 q=0.0 size=    2761kB time=00:00:20.96 bitrate=1079.2kbits/sframe=  546 fps= 48 q=0.0 size=    2889kB time=00:00:21.84 bitrate=1083.8kbits/sframe=  569 fps= 48 q=0.0 size=    3017kB time=00:00:22.76 bitrate=1086.0kbits/sframe=  595 fps= 48 q=0.0 size=    3145kB time=00:00:23.80 bitrate=1082.6kbits/sframe=  620 fps= 49 q=0.0 size=    3273kB time=00:00:24.80 bitrate=1081.2kbits/sframe=  644 fps= 48 q=0.0 size=    3397kB time=00:00:25.76 bitrate=1080.3kbits/sframe=  668 fps= 48 q=0.0 size=    3525kB time=00:00:26.72 bitrate=1080.8kbits/sframe=  692 fps= 48 q=0.0 size=    3653kB time=00:00:27.68 bitrate=1081.2kbits/sframe=  715 fps= 48 q=0.0 size=    3813kB time=00:00:28.60 bitrate=1092.2kbits/sframe=  740 fps= 48 q=0.0 size=    3941kB time=00:00:29.60 bitrate=1090.7kbits/sframe=  763 fps= 48 q=0.0 size=    4069kB time=00:00:30.52 bitrate=1092.2kbits/sframe=  789 fps= 48 q=0.0 size=    4206kB time=00:00:31.56 bitrate=1091.7kbits/sframe=  813 fps= 48 q=0.0 size=    4334kB time=00:00:32.52 bitrate=1091.7kbits/sframe=  838 fps= 48 q=0.0 size=    4462kB time=00:00:33.52 bitrate=1090.4kbits/sframe=  862 fps= 48 q=0.0 size=    4590kB time=00:00:34.48 bitrate=1090.5kbits/sframe=  887 fps= 48 q=0.0 size=    4718kB time=00:00:35.48 bitrate=1089.3kbits/sframe=  911 fps= 48 q=0.0 size=    4848kB time=00:00:36.44 bitrate=1089.9kbits/sframe=  934 fps= 48 q=0.0 size=    4976kB time=00:00:37.36 bitrate=1091.2kbits/sframe=  961 fps= 48 q=0.0 size=    5104kB time=00:00:38.44 bitrate=1087.8kbits/sframe=  986 fps= 48 q=0.0 size=    5232kB time=00:00:39.44 bitrate=1086.8kbits/sframe= 1011 fps= 48 q=0.0 size=    5360kB time=00:00:40.44 bitrate=1085.8kbits/sframe= 1036 fps= 48 q=0.0 size=    5518kB time=00:00:41.44 bitrate=1090.9kbits/sframe= 1057 fps= 48 q=0.0 size=    5646kB time=00:00:42.28 bitrate=1094.0kbits/sframe= 1080 fps= 48 q=0.0 size=    5774kB time=00:00:43.20 bitrate=1095.0kbits/sframe= 1105 fps= 48 q=0.0 size=    5902kB time=00:00:44.20 bitrate=1093.9kbits/sframe= 1132 fps= 48 q=0.0 size=    6030kB time=00:00:45.28 bitrate=1091.0kbits/sframe= 1156 fps= 48 q=0.0 size=    6199kB time=00:00:46.24 bitrate=1098.2kbits/sframe= 1179 fps= 48 q=0.0 size=    6295kB time=00:00:47.16 bitrate=1093.4kbits/sframe= 1203 fps= 48 q=0.0 size=    6455kB time=00:00:48.12 bitrate=1098.8kbits/sframe= 1229 fps= 48 q=0.0 size=    6583kB time=00:00:49.16 bitrate=1096.9kbits/sframe= 1256 fps= 48 q=0.0 size=    6679kB time=00:00:50.24 bitrate=1089.0kbits/sframe= 1278 fps= 48 q=0.0 size=    6807kB time=00:00:51.12 bitrate=1090.8kbits/sframe= 1300 fps= 48 q=0.0 size=    6927kB time=00:00:52.00 bitrate=1091.3kbits/sframe= 1321 fps= 48 q=0.0 size=    7055kB time=00:00:52.84 bitrate=1093.8kbits/sframe= 1345 fps= 48 q=0.0 size=    7183kB time=00:00:53.80 bitrate=1093.7kbits/sframe= 1367 fps= 48 q=0.0 size=    7311kB time=00:00:54.68 bitrate=1095.3kbits/sframe= 1393 fps= 48 q=0.0 size=    7439kB time=00:00:55.72 bitrate=1093.7kbits/sframe= 1418 fps= 48 q=0.0 size=    7568kB time=00:00:56.72 bitrate=1093.1kbits/sframe= 1443 fps= 48 q=0.0 size=    7696kB time=00:00:57.72 bitrate=1092.3kbits/sframe= 1469 fps= 48 q=0.0 size=    7824kB time=00:00:58.76 bitrate=1090.8kbits/sframe= 1490 fps= 48 q=0.0 size=    7920kB time=00:00:59.60 bitrate=1088.6kbits/sframe= 1511 fps= 48 q=0.0 size=    8048kB time=00:01:00.44 bitrate=1090.9kbits/sframe= 1537 fps= 48 q=0.0 size=    8196kB time=00:01:01.48 bitrate=1092.0kbits/sframe= 1561 fps= 48 q=0.0 size=    8324kB time=00:01:02.44 bitrate=1092.0kbits/sframe= 1585 fps= 48 q=0.0 size=    8452kB time=00:01:03.40 bitrate=1092.1kbits/sframe= 1608 fps= 48 q=0.0 size=    8580kB time=00:01:04.32 bitrate=1092.7kbits/sframe= 1632 fps= 48 q=0.0 size=    8676kB time=00:01:05.28 bitrate=1088.7kbits/sframe= 1656 fps= 48 q=0.0 size=    8836kB time=00:01:06.24 bitrate=1092.7kbits/sframe= 1680 fps= 48 q=0.0 size=    8944kB time=00:01:07.20 bitrate=1090.3kbits/sframe= 1704 fps= 48 q=0.0 size=    9104kB time=00:01:08.16 bitrate=1094.2kbits/sframe= 1727 fps= 48 q=0.0 size=    9232kB time=00:01:09.08 bitrate=1094.8kbits/sframe= 1754 fps= 48 q=0.0 size=    9360kB time=00:01:10.16 bitrate=1092.9kbits/sframe= 1777 fps= 48 q=0.0 size=    9488kB time=00:01:11.08 bitrate=1093.5kbits/sframe= 1801 fps= 48 q=0.0 size=    9613kB time=00:01:12.04 bitrate=1093.1kbits/sframe= 1826 fps= 48 q=0.0 size=    9741kB time=00:01:13.04 bitrate=1092.5kbits/sframe= 1851 fps= 48 q=0.0 size=    9869kB time=00:01:14.04 bitrate=1091.9kbits/sframe= 1874 fps= 48 q=0.0 size=    9997kB time=00:01:14.96 bitrate=1092.5kbits/sframe= 1901 fps= 48 q=0.0 size=   10157kB time=00:01:16.04 bitrate=1094.2kbits/sframe= 1923 fps= 48 q=0.0 size=   10270kB time=00:01:16.92 bitrate=1093.8kbits/sframe= 1947 fps= 48 q=0.0 size=   10398kB time=00:01:17.88 bitrate=1093.8kbits/sframe= 1972 fps= 48 q=0.0 size=   10526kB time=00:01:18.88 bitrate=1093.2kbits/sframe= 1997 fps= 48 q=0.0 size=   10686kB time=00:01:19.88 bitrate=1095.9kbits/sframe= 2022 fps= 48 q=0.0 size=   10814kB time=00:01:20.88 bitrate=1095.3kbits/sframe= 2044 fps= 48 q=0.0 size=   10942kB time=00:01:21.76 bitrate=1096.4kbits/sframe= 2069 fps= 48 q=0.0 size=   11074kB time=00:01:22.76 bitrate=1096.2kbits/sframe= 2095 fps= 48 q=0.0 size=   11170kB time=00:01:23.80 bitrate=1092.0kbits/sframe= 2117 fps= 48 q=0.0 size=   11330kB time=00:01:24.68 bitrate=1096.1kbits/sframe= 2141 fps= 48 q=0.0 size=   11426kB time=00:01:25.64 bitrate=1093.0kbits/sframe= 2164 fps= 48 q=0.0 size=   11554kB time=00:01:26.56 bitrate=1093.5kbits/sframe= 2189 fps= 48 q=0.0 size=   11702kB time=00:01:27.56 bitrate=1094.9kbits/sframe= 2214 fps= 48 q=0.0 size=   11830kB time=00:01:28.56 bitrate=1094.3kbits/sframe= 2237 fps= 48 q=0.0 size=   11958kB time=00:01:29.48 bitrate=1094.8kbits/sframe= 2258 fps= 48 q=0.0 size=   12086kB time=00:01:30.32 bitrate=1096.2kbits/sframe= 2282 fps= 48 q=0.0 size=   12214kB time=00:01:31.28 bitrate=1096.2kbits/sframe= 2307 fps= 48 q=0.0 size=   12347kB time=00:01:32.28 bitrate=1096.0kbits/sframe= 2332 fps= 48 q=0.0 size=   12475kB time=00:01:33.28 bitrate=1095.5kbits/sframe= 2355 fps= 48 q=0.0 size=   12635kB time=00:01:34.20 bitrate=1098.8kbits/sframe= 2380 fps= 48 q=0.0 size=   12763kB time=00:01:35.20 bitrate=1098.2kbits/sframe= 2401 fps= 47 q=0.0 size=   12923kB time=00:01:36.04 bitrate=1102.3kbits/sframe= 2428 fps= 48 q=0.0 size=   13019kB time=00:01:37.12 bitrate=1098.1kbits/sframe= 2464 fps= 48 q=0.0 size=   13116kB time=00:01:38.56 bitrate=1090.1kbits/sframe= 2500 fps= 48 q=0.0 Lsize=   13136kB time=00:01:40.00 bitrate=1076.1kbits/s
video:13117kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.140834%