Webm streaming issue with ffmpeg/ffserver - html

Question

I am trying to play the stream from ip camera in the browser. I am using ffmpeg and ffserver stack for that (both 2.4.2).
For now I can easily play video stream in browser using flash. But I would like to have ability to play it in native html5 player. And I need webm format to do that.
ffserver config snippet:
<Feed 0_webm.ffm>
File /tmp/0_webm.ffm
FileMaxSize 5M
ACL allow localhost
</Feed>
<Stream 0.webm>
Feed 0_webm.ffm
Format webm
NoAudio
</Stream>
<Stream test2.swf>
Feed feed2.ffm
Format swf
VideoCodec flv
VideoFrameRate 30
VideoBufferSize 50000
VideoBitRate 100
VideoQMin 1
VideoQMax 5
VideoSize 352x288
PreRoll 0
Noaudio
</Stream>
I execute this command to get stream from camera and pass it to a client through ffserver:
ffmpeg -rtsp_transport tcp -i rtsp://admin:admin#192.168.10.76:80 -vcodec libvpx r 10 -f webm http://localhost:8090/0_webm.ffm
But get "Broken pipe" error message (full ffmeg output):
ffmpeg version 2.4.2 Copyright (c) 2000-2014 the FFmpeg developers
built on Oct 6 2014 17:33:05 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
configuration: --prefix=/opt/ffmpeg --libdir=/opt/ffmpeg/lib/ --enable-shared --enable-avresample --disable-stripping --enable-gpl --enable-version3 --enable-runtime-cpudetect --build-suffix=.ffmpeg --enable-postproc --enable-x11grab --enable-libcdio --enable-vaapi --enable-vdpau --enable-bzlib --enable-gnutls --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libfaac --enable-libvo-aacenc --enable-nonfree --enable-libmp3lame --enable-libx264 --enable-libx265 --enable-libxvid --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libfdk_aac --enable-libopus --enable-pthreads --enable-zlib --enable-libvpx --enable-libfreetype --enable-libpulse --enable-debug=3
libavutil 54. 7.100 / 54. 7.100
libavcodec 56. 1.100 / 56. 1.100
libavformat 56. 4.101 / 56. 4.101
libavdevice 56. 0.100 / 56. 0.100
libavfilter 5. 1.100 / 5. 1.100
libavresample 2. 1. 0 / 2. 1. 0
libswscale 3. 0.100 / 3. 0.100
libswresample 1. 1.100 / 1. 1.100
libpostproc 53. 0.100 / 53. 0.100
Guessed Channel Layout for Input Stream #0.1 : mono
Input #0, rtsp, from 'rtsp://admin:admin#192.168.10.76:80':
Metadata:
title : RTSP Session/2.0
Duration: N/A, start: 0.000000, bitrate: 128 kb/s
Stream #0:0: Video: h264 (High), yuvj420p(pc, bt709), 1280x720 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 90k tbn, 50 tbc
Stream #0:1: Audio: pcm_alaw, 16000 Hz, 1 channels, s16, 128 kb/s
[swscaler # 0xcf97a0] deprecated pixel format used, make sure you did set range correctly
[libvpx # 0xd86fc0] v1.3.0
Output #0, webm, to 'http://localhost:8090/0_webm.ffm':
Metadata:
title : RTSP Session/2.0
encoder : Lavf56.4.101
Stream #0:0: Video: vp8 (libvpx), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 200 kb/s, 10 fps, 1k tbn, 10 tbc
Metadata:
encoder : Lavc56.1.100 libvpx
Stream #0:1: Audio: vorbis (libvorbis), 16000 Hz, mono, fltp
Metadata:
encoder : Lavc56.1.100 libvorbis
Stream mapping:
Stream #0:0 -> #0:0 (h264 (native) -> vp8 (libvpx))
Stream #0:1 -> #0:1 (pcm_alaw (native) -> vorbis (libvorbis))
Press [q] to stop, [?] for help
av_interleaved_write_frame(): Broken pipe
Last message repeated 1 times
frame= 2 fps=0.0 q=0.0 Lsize= 40kB time=00:00:00.23 bitrate=1371.2kbits/s
video:36kB audio:1kB subtitle:0kB other streams:0kB global headers:3kB muxing overhead: 7.514220%
Conversion failed!
If I run the same command without -f webm, I get no error and it looks like working. But in this case I can't play it in browser (Chrome for instance).
Does anybody know how to fix "Broken pipe issue"? Will be happy to get any your help or advises. Thanks in advance.