The firCount property of the RTCRtpStreamStats dictionary indicates the number of Full Intra Request (FIR) packets have been sent by the receiver to the sender. This is a measure of how often the stream falls behind and has to skip frames in order to catch up.
Syntax
var firCount = RTCRtpStreamStats.firCount;
Value
An integer value indicating how many FIR packets have been received by the sender during the current connection. This value is available only on receivers for video tracks.
The receiver sends a FIR packet to the sender any time it falls bahind or loses packets and cannot decode the incoming stream any longer because of the lost data. This tells the sender to send a full frame instead of a delta frame, so that the receiver can catch up.
The higher firCount is, the more often frames were dropped, which may be an indication that the media's bit rate is too high for the available bandwidth, or that the receiving device is overburdened and is therefore unable to process the incoming data.
Specifications
| Specification | Status | Comment |
| Identifiers for WebRTC's Statistics APIThe definition of 'RTCInboundRtpStreamStats: firCount' in that specification. | Candidate Recommendation | Initial definition. |
| Identifiers for WebRTC's Statistics APIThe definition of 'RTCOutboundRtpStreamStats: firCount' in that specification. | Candidate Recommendation | Initial definition. |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Update compatibility data on GitHub
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
firCount
|
Chrome
No support No |
Edge
No support No |
Firefox
Full support 55 |
IE
No support No |
Opera
No support No |
Safari
? |
WebView Android
No support No |
Chrome Android
No support No |
Firefox Android
Full support 55 |
Opera Android
No support No |
Safari iOS
? |
Samsung Internet Android
No support No |
Legend
- Full support
- Full support
- No support
- No support
- Compatibility unknown
- Compatibility unknown
RTCRtpStreamStats.firCount by Mozilla Contributors is licensed under CC-BY-SA 2.5.
