The webm video container live-streams fantastically well. It's just the MP4 container that is broken and doesn't live-stream.
Note that if you put H264 in an MPEG2-TS container that it will stream fine as well, but unfortunately that's not supported by browsers. (It also is inefficient, which makes it a poor choice.)
There is fragmented MP4, (usually called fMP4), which is a single MP4 file with multiple fragments inside. The last time I looked this wasn't supported by any browser, but now it looks like there's been work to integrate it into chrome and firefox.
The reason that single-file live-streaming is useful is that you can point the video tag's SRC at a URL that just calls popen on an FFMPEG process and transcode video on the fly, or even create new content immediately.
Note that if you put H264 in an MPEG2-TS container that it will stream fine as well, but unfortunately that's not supported by browsers. (It also is inefficient, which makes it a poor choice.)
There is fragmented MP4, (usually called fMP4), which is a single MP4 file with multiple fragments inside. The last time I looked this wasn't supported by any browser, but now it looks like there's been work to integrate it into chrome and firefox.
The reason that single-file live-streaming is useful is that you can point the video tag's SRC at a URL that just calls popen on an FFMPEG process and transcode video on the fly, or even create new content immediately.