You can do this with the WebM container, not with MP4. The reason is that the MP4 container requires the video frames to be segmented properly and marked into a metadata part of the file which can be in front or end but cannot be created with an infinite stream. WebM (i.e. VP8/9) is not supported on Apple's platform so you also have to have a fallback of HLS + H.264. But in general its doable with WebM and works pretty nice with low latency compared to segmented formats like HLS and DASH. It's impossible to cache on a CDN of course, which is not the case with HLS.
i actually use fragmented mp4 streams as a method to live stream video directly to a browsers video tag. I can point any common browser directly to that stream and it will start playing immediately... ive written a small utility to proxy requests to an RTMP server and repackage the stream for HTTP clients using just a little bit of overhead.
Not really. The browser need to read the header to know where the video frames are in the file.
The table with pointers to all the frames cannot be made before all the frames are encoded and their size is known. Then you can shuffle the file and move the table to the start (known as faststarting), and in that case you can start viewing the video before it is completely downloaded.
This can't be used for live content, since the encoded frames does not exist at the time you start viewing in that case.
Does it have to know the information for all frames, or just the key frames? If it’s the later, then you could encode so the initial table, has X key frames spread out over a few hours, then force a frame to exist in those locations when encoding the live stream.
You cannot use MP4 for live streaming. The file cannot be demuxed properly if the moov soon is incomplete. Frames cannot be located, it is impossible to decode it in the end. With live streaming, you don't ever have the full file until the end of the event, which is why you cannot stream it. Video streaming with a complete file is possible of course, but that is nothing special nor related to this discussion.
