create a separate playbackSpeeder element

apps/ex_nvr/lib/ex_nvr/elements/recording/timestamper.ex

@@ -12,16 +12,6 @@ defmodule ExNVR.Elements.Recording.Timestamper do
               start_date: [
                 spec: Membrane.Time.t(),
                 description: "The start date of the first buffer"
-              ],
-              playback_speed: [
-                spec: float(),
-                default: 1,
-                description: """
-                The playback speed rate to either speed up or slow down the stream.
-                * A value lower than 1: speeds up the stream.
-                * A value greater than 1: slows down the stream.
-                * 1 is the default value which is the normal stream speed.
-                """
               ]
 
   def_input_pad :input,
@@ -36,12 +26,10 @@ defmodule ExNVR.Elements.Recording.Timestamper do
 
   @impl true
   def handle_init(_ctx, options) do
-    IO.inspect("Playback from TimeStamper: #{options.playback_speed}")
     {[],
      %{
        offset: options.offset,
        start_date: options.start_date,
-       playback_speed: options.playback_speed,
        last_buffer_dts_or_pts: nil
      }}
   end
@@ -59,10 +47,9 @@ defmodule ExNVR.Elements.Recording.Timestamper do
     buffer_duration = Membrane.Buffer.get_dts_or_pts(buffer) - state.last_buffer_dts_or_pts
     metadata = Map.put(buffer.metadata, :timestamp, state.start_date + buffer_duration)
 
-    IO.inspect("Old #{(buffer.pts + state.offset)} Multiply by #{state.playback_speed} gives: #{(buffer.pts + state.offset) * state.playback_speed}")
     buffer = %{
       buffer
-      | pts: (buffer.pts + state.offset) * state.playback_speed,
+      | pts: buffer.pts + state.offset,
         dts: buffer.dts + state.offset,
         metadata: metadata
     }

apps/ex_nvr/lib/ex_nvr/elements/recording_bin.ex

@@ -57,16 +57,6 @@ defmodule ExNVR.Elements.RecordingBin do
                 Note that if both `duration` and `end_date` are provided, an
                 `end_of_stream` will be sent on the first satisfied condition.
                 """
-              ],
-              playback_speed: [
-                spec: float(),
-                default: 1,
-                description: """
-                The playback speed rate to either speed up or slow down the stream.
-                * A value lower than 1: speeds up the stream.
-                * A value greater than 1: slows down the stream.
-                * 1 is the default value which is the normal stream speed.
-                """
               ]
 
   def_output_pad :video,
@@ -123,8 +113,7 @@ defmodule ExNVR.Elements.RecordingBin do
       |> add_depayloader(track, id)
       |> child({:timestamper, id}, %Timestamper{
         offset: state.recording_duration,
-        start_date: Membrane.Time.from_datetime(state.current_recording.start_date),
-        playback_speed: state.playback_speed
+        start_date: Membrane.Time.from_datetime(state.current_recording.start_date)
       })
       |> get_child(:funnel)
     ]

apps/ex_nvr/lib/ex_nvr/hls/playback_speeder.ex

@@ -0,0 +1,47 @@
+defmodule ExNVR.HLS.PlaybackSpeeder do
+  @moduledoc """
+  Rewrites buffers pts according to the prodivded playback rate.
+  """
+
+  use Membrane.Filter
+
+  def_input_pad :input,
+    demand_mode: :auto,
+    demand_unit: :buffers,
+    accepted_format: _any,
+    availability: :always
+
+  def_output_pad :output,
+    demand_mode: :auto,
+    accepted_format: _any
+
+  def_options rate: [
+                spec: float(),
+                default: 1,
+                description: """
+                The playback speed rate to either speed up or slow down the stream.
+                * A value lower than 1: speeds up the stream.
+                * A value greater than 1: slows down the stream.
+                * 1 is the default value which is the normal stream speed.
+                """
+              ]
+
+  @impl true
+  def handle_init(_ctx, options) do
+    state =
+      options
+      |> Map.from_struct()
+
+    {[], state}
+  end
+
+  @impl true
+  def handle_process(:input, buffer, _ctx, state) do
+    buffer = %{
+      buffer
+      | pts: trunc(buffer.pts  * state.rate)
+    }
+
+    {[buffer: {:output, buffer}], state}
+  end
+end

apps/ex_nvr/lib/ex_nvr/pipelines/hls_playback.ex

@@ -7,7 +7,7 @@ defmodule ExNVR.Pipelines.HlsPlayback do
 
   require Membrane.Logger
 
-  alias ExNVR.Elements
+  alias ExNVR.{Elements, HLS}
   alias ExNVR.Pipeline.Output
 
   @call_timeout :timer.seconds(10)
@@ -43,11 +43,11 @@ defmodule ExNVR.Pipelines.HlsPlayback do
     spec = [
       child(:source, %Elements.RecordingBin{
         device: options[:device],
-        start_date: options[:start_date],
-        playback_speed: playback_speed
+        start_date: options[:start_date]
       })
       |> via_out(:video)
-      |> child(:realtimer, ExNVR.Elements.Realtimer)
+      |> child(:realtimer, Elements.Realtimer)
+      |> child(:playback_speeder, %HLS.PlaybackSpeeder{rate: playback_speed})
       |> via_in(Pad.ref(:video, :playback), options: [resolution: options[:resolution]])
       |> child(:sink, %Output.HLS{
         location: options[:directory],

apps/ex_nvr_web/assets/js/app.js

@@ -85,7 +85,6 @@ let Hooks = {
             this.el.addEventListener("ratechange", this.changePlaybackspeed);
         },
         changePlaybackspeed(event) {
-            console.log(event)
             let video = document.getElementById("live-video");
             var rate = video.playbackRate;
             if (rate != 1) {
@@ -110,7 +109,6 @@ let Hooks = {
                         rate = 0.25;
                         break;
                 }
-                alert(rate)
                 window.TimelineHook.pushEvent("playback_speed", {
                     speedRate: rate,
                 })

apps/ex_nvr_web/lib/ex_nvr_web/live/dashboard_live.ex

@@ -246,7 +246,7 @@ defmodule ExNVRWeb.DashboardLive do
   def handle_event("playback_speed", %{"speedRate" => speed_rate}, socket) do
     socket =
       socket
-      |> assign_start_date(socket.assigns.current_datetime)
+      |> assign(start_date: socket.assigns.current_datetime)
       |> live_view_enabled?()
       |> maybe_push_stream_event(socket.assigns.current_datetime, speed_rate)