Rendering a fake waveform when playing music without any video frames.

amethyst/src/main/java/com/vitorpamplona/amethyst/service/playback/composable/RenderVideoPlayer.kt

@@ -23,6 +23,8 @@ package com.vitorpamplona.amethyst.service.playback.composable
 import androidx.annotation.OptIn
 import androidx.compose.foundation.gestures.detectTapGestures
 import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.height
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.MutableState
 import androidx.compose.runtime.mutableStateOf
@@ -44,7 +46,7 @@ import com.vitorpamplona.amethyst.service.playback.composable.controls.RenderCen
 import com.vitorpamplona.amethyst.service.playback.composable.controls.RenderTopButtons
 import com.vitorpamplona.amethyst.service.playback.composable.controls.TopGradientOverlay
 import com.vitorpamplona.amethyst.service.playback.composable.mediaitem.LoadedMediaItem
-import com.vitorpamplona.amethyst.service.playback.composable.wavefront.Waveform
+import com.vitorpamplona.amethyst.service.playback.composable.wavefront.AudioPlayingAnimation
 import com.vitorpamplona.amethyst.service.playback.diskCache.isLiveStreaming
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
 
@@ -118,7 +120,11 @@ fun RenderVideoPlayer(
             contentScale = contentScale,
         )
 
-        mediaItem.src.waveformData?.let { Waveform(it, controllerState, Modifier.align(Alignment.Center)) }
+        AudioPlayingAnimation(
+            controllerState,
+            mediaItem.src.waveformData,
+            Modifier.fillMaxSize().align(Alignment.Center),
+        )
 
         if (showControls) {
             TopGradientOverlay(

amethyst/src/main/java/com/vitorpamplona/amethyst/service/playback/composable/wavefront/AudioPlayingAnimation.kt

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.service.playback.composable.wavefront
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.media3.common.C
+import androidx.media3.common.Player
+import androidx.media3.common.Tracks
+import com.vitorpamplona.amethyst.service.playback.composable.MediaControllerState
+import com.vitorpamplona.amethyst.service.playback.composable.WaveformData
+
+fun Tracks.isAudio() = groups.none { it.type == C.TRACK_TYPE_VIDEO }
+
+@Composable
+fun AudioPlayingAnimation(
+    controllerState: MediaControllerState,
+    waveform: WaveformData?,
+    modifier: Modifier = Modifier,
+) {
+    var isAudio by remember { mutableStateOf(controllerState.controller.currentTracks.isAudio()) }
+
+    DisposableEffect(controllerState.controller) {
+        val listener =
+            object : Player.Listener {
+                override fun onTracksChanged(tracks: Tracks) {
+                    super.onTracksChanged(tracks)
+                    isAudio = tracks.isAudio()
+                }
+            }
+        controllerState.controller.addListener(listener)
+        onDispose { controllerState.controller.removeListener(listener) }
+    }
+
+    if (isAudio) {
+        if (waveform != null) {
+            Waveform(waveform, controllerState, modifier)
+        } else {
+            FakeWaveformAnimation(
+                mediaControllerState = controllerState,
+                modifier = modifier,
+            )
+        }
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/service/playback/composable/wavefront/FakeWaveformAnimation.kt

@@ -0,0 +1,153 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.service.playback.composable.wavefront
+
+import androidx.compose.foundation.Canvas
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.requiredHeight
+import androidx.compose.foundation.layout.width
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.MutableFloatState
+import androidx.compose.runtime.mutableFloatStateOf
+import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.CornerRadius
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.geometry.Size
+import androidx.compose.ui.graphics.Brush
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.drawscope.Fill
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.unit.dp
+import androidx.media3.common.Player
+import com.vitorpamplona.amethyst.service.playback.composable.MediaControllerState
+import com.vitorpamplona.amethyst.ui.theme.ThemeComparisonColumn
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.conflate
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.onStart
+import kotlin.math.sin
+
+@Composable
+fun FakeWaveformAnimation(
+    mediaControllerState: MediaControllerState,
+    modifier: Modifier,
+) {
+    val waveformProgress = remember { mutableFloatStateOf(0F) }
+
+    FakeWaveformAnimation(waveformProgress, 50, modifier)
+
+    val restartFlow = remember { mutableIntStateOf(0) }
+
+    // Keeps the screen on while playing and viewing videos.
+    DisposableEffect(key1 = mediaControllerState.controller) {
+        val listener =
+            object : Player.Listener {
+                override fun onIsPlayingChanged(isPlaying: Boolean) {
+                    // doesn't consider the mutex because the screen can turn off if the video
+                    // being played in the mutex is not visible.
+                    if (isPlaying) {
+                        restartFlow.intValue += 1
+                    }
+                }
+            }
+
+        mediaControllerState.controller.addListener(listener)
+        onDispose { mediaControllerState.controller.removeListener(listener) }
+    }
+
+    LaunchedEffect(key1 = restartFlow.intValue) {
+        pollCurrentPosition(mediaControllerState.controller).collect { value ->
+            waveformProgress.floatValue = (value % 5000.0f) / 5000.0f
+        }
+    }
+}
+
+fun pollCurrentPosition(controller: Player) =
+    flow {
+        while (controller.currentPosition <= controller.duration) {
+            emit(controller.currentPosition)
+            delay(100)
+        }
+    }.onStart {
+        emit(controller.currentPosition)
+    }.conflate()
+
+@Preview
+@Composable
+fun FakeWaveformAnimationPreview() {
+    val state =
+        remember {
+            mutableFloatStateOf((500 % 1000.0f) / 1000.0f)
+        }
+    ThemeComparisonColumn {
+        FakeWaveformAnimation(state, 50, Modifier.width(200.dp))
+    }
+}
+
+@Composable
+fun FakeWaveformAnimation(
+    waveformProgress: MutableFloatState,
+    barCount: Int = 50,
+    modifier: Modifier = Modifier,
+) {
+    val barBrush =
+        Brush.linearGradient(
+            colors = listOf(Color(0xff2598cf), Color(0xff652d80)),
+            start = Offset(0.2f * 128f, 0f),
+            end = Offset(0.2f * 128f + 128f, 0f),
+        )
+
+    Canvas(
+        modifier =
+            modifier
+                .fillMaxWidth()
+                .requiredHeight(48.dp)
+                .padding(horizontal = 10.dp),
+    ) {
+        val barWidth = 3.dp.toPx()
+        val barPadding = 2.dp.toPx()
+        val barRadius = 2.dp.toPx()
+        val totalBarWidth = barWidth + barPadding
+        val startX = (size.width - (barCount * totalBarWidth - barPadding)) / 2f
+
+        for (i in 0 until barCount) {
+            val phase = (i.toFloat() / barCount) * 2f * Math.PI.toFloat()
+            val wave = sin(waveformProgress.floatValue * 2f * Math.PI.toFloat() + phase)
+            val barFraction = ((wave + 1f) / 2f)
+            val barHeight = size.height * barFraction
+            val x = startX + i * totalBarWidth
+            val y = (size.height - barHeight) / 2f
+
+            drawRoundRect(
+                brush = barBrush,
+                topLeft = Offset(x, y),
+                size = Size(barWidth, barHeight),
+                cornerRadius = CornerRadius(barRadius, barRadius),
+                style = Fill,
+            )
+        }
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/service/playback/composable/wavefront/Waveform.kt

@@ -42,6 +42,7 @@ import com.vitorpamplona.amethyst.ui.components.AudioWaveformReadOnly
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.conflate
 import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.onStart
 
 @Composable
 fun Waveform(
@@ -73,22 +74,18 @@ fun Waveform(
     }
 
     LaunchedEffect(key1 = restartFlow.intValue) {
-        pollCurrentDuration(mediaControllerState.controller).collect { value -> waveformProgress.floatValue = value }
+        pollCurrentRelativePosition(mediaControllerState.controller).collect { value -> waveformProgress.floatValue = value }
-    }
-
-    LaunchedEffect(Unit) {
-        delay(500)
-        val position = mediaControllerState.controller?.let { it.currentPosition / it.duration.toFloat() } ?: 0f
-        waveformProgress.floatValue = position
     }
 }
 
-private fun pollCurrentDuration(controller: Player) =
+fun pollCurrentRelativePosition(controller: Player) =
     flow {
         while (controller.currentPosition <= controller.duration) {
             emit(controller.currentPosition / controller.duration.toFloat())
             delay(100)
         }
+    }.onStart {
+        emit(controller.currentPosition / controller.duration.toFloat())
     }.conflate()
 
 @Composable