Improvements to statistical output from srt-live-transmit

[gissleh]

I'm evaluating SRT for stream contribution, and the early results with using the built-in live transmit tool has been promising once I found out where to put the latency argument. My use case is using the srt-live-transmit as a process spawned from a central management system, and for that good monitoring information is important.

However, I have noticed the statistics option for srt-live-transmit does not output all monitoring data it has access to, and the format – while good for human readability and debugging – is not very suited for parsing by client programs.

I have added an option for that in a local copy of the repo that prints in a JSON format (except not prettified like the example below), but I want to see what you think about this before cleaning that code up and sending a pull request.

{
    "sid": 948948699,
    "time": 3310824,
    "window": {
        "flow": 8192,
        "congestion": 8192,
        "flight": 0
    },
    "link": {
        "rtt": 253.417,
        "bandwidth": 113.28,
        "maxBandwidth": 30
    },
    "send": {
        "packets": 0,
        "packetsLost": 0,
        "packetsDropped": 0,
        "packetsRetransmitted": 0,
        "bytes": 0,
        "bytesDropped": 0,
        "mbitRate": 0
    },
    "recv": {
        "packets": 886507,
        "packetsLost": 17,
        "packetsDopped": 0,
        "packetsRetransmitted": 39,
        "packetsBelated": 19,
        "bytes": 1114118900,
        "bytesLost": 20222,
        "bytesDropped": 0,
        "mbitRate": 2.69206
    }
}

[rebotnix]

Like that, let´s merge to the main master please!

[ethouris]

I don't exactly understand how it is supposed to work. Can anyone make a PR for it?

[gissleh]

#356

The output in that PR is a json stream where each output is an object that spans just one line, making it compatible with parsers that reads newline-delimited json streams and concatenated json streams. It's best used with -q to avoid having to filter out non-json output from stderr. Since there are no string values, writing JSON without an external library should be safe.