# FPSLimiter # FPSLimiter ```cpp #include class FPSLimiter ``` [Defined in src/av/include/icy/av/fpscounter.h:152](https://github.com/auscaster/icey/blob/main/src/av/include/icy/av/fpscounter.h#L152) > **Inherits:** [`PacketProcessor`](https://auscaster.com/icey/docs/api-reference/icy-PacketProcessor.md#packetprocessor) [PacketStream](https://auscaster.com/icey/docs/api-reference/icy-PacketStream.md#packetstream) processor that caps packet throughput to a maximum FPS. If the observed frame rate exceeds the configured FPS budget, packets are dropped until the rate falls back under the limit. Note that previous processors must not fragment packets, otherwise this class will not be accurate, and the packet drop rate will be too high. ## List of all members | Name | Kind | Owner | |------|------|-------| | [`emitter`](#emitter-6) | `variable` | Declared here | | [`FPSLimiter`](#fpslimiter-1) | `function` | Declared here | | [`process`](#process-11) | `function` | Declared here | | [`onStreamStateChange`](#onstreamstatechange-6) | `function` | Declared here | | [`_max`](#_max) | `variable` | Declared here | | [`_videoOnly`](#_videoonly) | `variable` | Declared here | | [`_counter`](#_counter) | `variable` | Declared here | | [`PacketProcessor`](https://auscaster.com/icey/docs/api-reference/icy-PacketProcessor.md#packetprocessor-1) | `function` | Inherited from [`PacketProcessor`](https://auscaster.com/icey/docs/api-reference/icy-PacketProcessor.md#packetprocessor) | | [`process`](https://auscaster.com/icey/docs/api-reference/icy-PacketProcessor.md#process-1) | `function` | Inherited from [`PacketProcessor`](https://auscaster.com/icey/docs/api-reference/icy-PacketProcessor.md#packetprocessor) | | [`accepts`](https://auscaster.com/icey/docs/api-reference/icy-PacketProcessor.md#accepts-1) | `function` | Inherited from [`PacketProcessor`](https://auscaster.com/icey/docs/api-reference/icy-PacketProcessor.md#packetprocessor) | | [`operator<<`](https://auscaster.com/icey/docs/api-reference/icy-PacketProcessor.md#operator-69) | `function` | Inherited from [`PacketProcessor`](https://auscaster.com/icey/docs/api-reference/icy-PacketProcessor.md#packetprocessor) | | [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter-1) | `function` | Inherited from [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter) | | [`~PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter-2) | `function` | Inherited from [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter) | | [`emit`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#emit-1) | `function` | Inherited from [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter) | | [`emit`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#emit-2) | `function` | Inherited from [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter) | | [`emit`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#emit-3) | `function` | Inherited from [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter) | | [`emit`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#emit-4) | `function` | Inherited from [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter) | | [`emit`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#emit-5) | `function` | Inherited from [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter) | | [`getEmitter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#getemitter) | `function` | Inherited from [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter) | | [`retention`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#retention-1) | `function` | Inherited from [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter) | | [`onStreamStateChange`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#onstreamstatechange-1) | `function` | Inherited from [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter) | | [`_emitter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#_emitter) | `variable` | Inherited from [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter) | | [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter-3) | `function` | Inherited from [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter) | | [`operator=`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#operator-72) | `function` | Inherited from [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter) | | [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter-4) | `function` | Inherited from [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter) | | [`operator=`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#operator-73) | `function` | Inherited from [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter) | ## Inherited from [`PacketProcessor`](https://auscaster.com/icey/docs/api-reference/icy-PacketProcessor.md#packetprocessor) | Kind | Name | Description | |------|------|-------------| | `function` | [`PacketProcessor`](https://auscaster.com/icey/docs/api-reference/icy-PacketProcessor.md#packetprocessor-1) `inline` | | | `function` | [`process`](https://auscaster.com/icey/docs/api-reference/icy-PacketProcessor.md#process-1) `virtual` | This method performs processing on the given packet and emits the result. | | `function` | [`accepts`](https://auscaster.com/icey/docs/api-reference/icy-PacketProcessor.md#accepts-1) `virtual` `inline` | This method ensures compatibility with the given packet type. Return false to reject the packet. | | `function` | [`operator<<`](https://auscaster.com/icey/docs/api-reference/icy-PacketProcessor.md#operator-69) `virtual` `inline` | [Stream](https://auscaster.com/icey/docs/api-reference/icy-Stream.md#stream) operator alias for [process()](https://auscaster.com/icey/docs/api-reference/icy-PacketProcessor.md#process-1) | ## Inherited from [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter) | Kind | Name | Description | |------|------|-------------| | `function` | [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter-1) | Construct the adapter, binding it to the given packet signal. | | `function` | [`~PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter-2) `virtual` `inline` | | | `function` | [`emit`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#emit-1) `virtual` | Emit a mutable raw buffer as a packet. | | `function` | [`emit`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#emit-2) `virtual` | Emit a read-only raw buffer as a packet (data is copied internally). | | `function` | [`emit`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#emit-3) `virtual` | Emit a string as a packet (data is copied internally). | | `function` | [`emit`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#emit-4) `virtual` | Emit a flag-only packet carrying no payload data. | | `function` | [`emit`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#emit-5) `virtual` | Emit an existing packet directly onto the outgoing signal. | | `function` | [`getEmitter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#getemitter) | Returns a reference to the outgoing packet signal. | | `function` | [`retention`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#retention-1) `virtual` `const` | Returns how this adapter treats incoming packet lifetime. Most adapters are synchronous and therefore only borrow the packet for the current call chain. Queue-style adapters override this to advertise that they clone before deferred use. Callers may treat the first adapter reporting Cloned or Retained as the explicit ownership boundary in the stream graph. | | `function` | [`onStreamStateChange`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#onstreamstatechange-1) `virtual` `inline` | Called by the [PacketStream](https://auscaster.com/icey/docs/api-reference/icy-PacketStream.md#packetstream) to notify when the internal [Stream](https://auscaster.com/icey/docs/api-reference/icy-Stream.md#stream) state changes. On receiving the Stopped state, it is the responsibility of the adapter to have ceased all outgoing packet transmission, especially in multi-thread scenarios. | | `variable` | [`_emitter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#_emitter) | | | `function` | [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter-3) | NonCopyable and NonMovable. | | `function` | [`operator=`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#operator-72) | Deleted assignment operator. | | `function` | [`PacketStreamAdapter`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#packetstreamadapter-4) | Deleted constructor. | | `function` | [`operator=`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#operator-73) | Deleted assignment operator. | ## Public Attributes | Return | Name | Description | |--------|------|-------------| | [`PacketSignal`](https://auscaster.com/icey/docs/api-reference/base.md#packetsignal) | [`emitter`](#emitter-6) | | --- ### emitter ```cpp PacketSignal emitter ``` Type: [`PacketSignal`](https://auscaster.com/icey/docs/api-reference/base.md#packetsignal) [Defined in src/av/include/icy/av/fpscounter.h:192](https://github.com/auscaster/icey/blob/main/src/av/include/icy/av/fpscounter.h#L192) ## Public Methods | Return | Name | Description | |--------|------|-------------| | | [`FPSLimiter`](#fpslimiter-1) `inline` | Construct the limiter. | | `void` | [`process`](#process-11) `virtual` `inline` | [Process](https://auscaster.com/icey/docs/api-reference/icy-Process.md#process-3) a packet: forward it if within the rate limit, drop it otherwise. | | `void` | [`onStreamStateChange`](#onstreamstatechange-6) `virtual` `inline` | Reset the FPS counter when the stream state changes. | --- ### FPSLimiter `inline` ```cpp inline FPSLimiter(int max, bool videoOnly = false) ``` [Defined in src/av/include/icy/av/fpscounter.h:158](https://github.com/auscaster/icey/blob/main/src/av/include/icy/av/fpscounter.h#L158) Construct the limiter. #### Parameters | Parameter | Type | Description | |-----------|------|-------------| | `max` | `int` | The maximum allowed frame rate in frames per second. | | `videoOnly` | `bool` | If true, non-VideoPacket packets are always forwarded regardless of rate. | --- ### process `virtual` `inline` ```cpp virtual inline void process(IPacket & packet) ``` [Defined in src/av/include/icy/av/fpscounter.h:167](https://github.com/auscaster/icey/blob/main/src/av/include/icy/av/fpscounter.h#L167) [Process](https://auscaster.com/icey/docs/api-reference/icy-Process.md#process-3) a packet: forward it if within the rate limit, drop it otherwise. #### Reimplements - [`PacketProcessor::process`](https://auscaster.com/icey/docs/api-reference/icy-PacketProcessor.md#process-1) #### Parameters | Parameter | Type | Description | |-----------|------|-------------| | `packet` | [`IPacket`](https://auscaster.com/icey/docs/api-reference/icy-IPacket.md#ipacket) & | The incoming packet to evaluate. | --- ### onStreamStateChange `virtual` `inline` ```cpp virtual inline void onStreamStateChange(const PacketStreamState &) ``` [Defined in src/av/include/icy/av/fpscounter.h:187](https://github.com/auscaster/icey/blob/main/src/av/include/icy/av/fpscounter.h#L187) Reset the FPS counter when the stream state changes. #### Reimplements - [`PacketStreamAdapter::onStreamStateChange`](https://auscaster.com/icey/docs/api-reference/icy-PacketStreamAdapter.md#onstreamstatechange-1) ## Protected Attributes | Return | Name | Description | |--------|------|-------------| | `int` | [`_max`](#_max) | | | `bool` | [`_videoOnly`](#_videoonly) | | | [`legacy::FPSCounter`](https://auscaster.com/icey/docs/api-reference/icy-av-legacy-FPSCounter.md#fpscounter) | [`_counter`](#_counter) | | --- ### _max ```cpp int _max ``` [Defined in src/av/include/icy/av/fpscounter.h:195](https://github.com/auscaster/icey/blob/main/src/av/include/icy/av/fpscounter.h#L195) --- ### _videoOnly ```cpp bool _videoOnly ``` [Defined in src/av/include/icy/av/fpscounter.h:196](https://github.com/auscaster/icey/blob/main/src/av/include/icy/av/fpscounter.h#L196) --- ### _counter ```cpp legacy::FPSCounter _counter ``` Type: [`legacy::FPSCounter`](https://auscaster.com/icey/docs/api-reference/icy-av-legacy-FPSCounter.md#fpscounter) [Defined in src/av/include/icy/av/fpscounter.h:197](https://github.com/auscaster/icey/blob/main/src/av/include/icy/av/fpscounter.h#L197)