Always treat waveform as List<Float> (#1663)

[MSC3246](https://github.com/matrix-org/matrix-spec-proposals/pull/3246) specifies the waveform as a list of ints because:

> Because floating point numbers are not allowed in Matrix events

Though DSP on audio data is almost always done using their floating point representation.
This PR brings the float<->int rescaling in the `matrix` module so that the application code can always work with float waveform samples.

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/factories/event/TimelineItemContentMessageFactory.kt

@@ -29,7 +29,6 @@ import io.element.android.features.messages.impl.timeline.model.event.TimelineIt
 import io.element.android.features.messages.impl.timeline.model.event.TimelineItemVoiceContent
 import io.element.android.features.messages.impl.timeline.util.FileExtensionExtractor
 import io.element.android.features.messages.impl.timeline.util.toHtmlDocument
-import io.element.android.features.messages.impl.voicemessages.fromMSC3246range
 import io.element.android.libraries.androidutils.filesize.FileSizeFormatter
 import io.element.android.libraries.core.mimetype.MimeTypes
 import io.element.android.libraries.featureflag.api.FeatureFlagService
@@ -118,7 +117,7 @@ class TimelineItemContentMessageFactory @Inject constructor(
                     mediaSource = messageType.source,
                     duration = messageType.info?.duration ?: Duration.ZERO,
                     mimeType = messageType.info?.mimetype ?: MimeTypes.OctetStream,
-                    waveform = messageType.details?.waveform?.fromMSC3246range()?.toImmutableList() ?: persistentListOf(),
+                    waveform = messageType.details?.waveform?.toImmutableList() ?: persistentListOf(),
                 )
                 else -> TimelineItemAudioContent(
                     body = messageType.body,

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/voicemessages/WaveformUtils.kt

@@ -1,28 +0,0 @@
-/*
- * Copyright (c) 2023 New Vector Ltd
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package io.element.android.features.messages.impl.voicemessages
-
-/**
- * Resizes the given [0;1024] int list as per unstable MSC3246 spec
- * to a [0;1] range float list to be used for waveform rendering.
- */
-internal fun List<Int>.fromMSC3246range(): List<Float> = map { it / 1024f }
-
-/**
- * Resizes the given [0;1] float list to [0;1024] int list as per unstable MSC3246 spec.
- */
-internal fun List<Float>.toMSC3246range(): List<Int> = map { (it * 1024).toInt() }

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/voicemessages/composer/VoiceMessageComposerPresenter.kt

@@ -28,7 +28,6 @@ import androidx.compose.runtime.setValue
 import androidx.core.net.toUri
 import androidx.lifecycle.Lifecycle
 import io.element.android.features.messages.impl.voicemessages.VoiceMessageException
-import io.element.android.features.messages.impl.voicemessages.toMSC3246range
 import io.element.android.libraries.architecture.Presenter
 import io.element.android.libraries.di.RoomScope
 import io.element.android.libraries.di.SingleIn
@@ -219,7 +218,7 @@ class VoiceMessageComposerPresenter @Inject constructor(
         val result = mediaSender.sendVoiceMessage(
             uri = file.toUri(),
             mimeType = mimeType,
-            waveForm = waveform.toMSC3246range(),
+            waveForm = waveform,
         )
 
         if (result.isFailure) {

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/media/AudioDetails.kt

@@ -20,5 +20,5 @@ import java.time.Duration
 
 data class AudioDetails(
     val duration: Duration,
-    val waveform: List<Int>,
+    val waveform: List<Float>,
 )

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/room/MatrixRoom.kt

@@ -195,7 +195,7 @@ interface MatrixRoom : Closeable {
     suspend fun sendVoiceMessage(
         file: File,
         audioInfo: AudioInfo,
-        waveform: List<Int>,
+        waveform: List<Float>,
         progressCallback: ProgressCallback?
     ): Result<MediaUploadHandler>
 

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/media/AudioDetails.kt

@@ -21,10 +21,26 @@ import org.matrix.rustcomponents.sdk.UnstableAudioDetailsContent as RustAudioDet
 
 fun RustAudioDetails.map(): AudioDetails = AudioDetails(
     duration = duration,
-    waveform = waveform.map { it.toInt() },
+    waveform = waveform.fromMSC3246range(),
 )
 
 fun AudioDetails.map(): RustAudioDetails = RustAudioDetails(
     duration = duration,
-    waveform = waveform.map { it.toUShort() }
+    waveform = waveform.toMSC3246range()
 )
+
+/**
+ * Resizes the given [0;1024] int list as per unstable MSC3246 spec
+ * to a [0;1] float list to be used for waveform rendering.
+ *
+ * https://github.com/matrix-org/matrix-spec-proposals/blob/travis/msc/audio-waveform/proposals/3246-audio-waveform.md
+ */
+internal fun List<UShort>.fromMSC3246range(): List<Float> = map { it.toInt() / 1024f }
+
+/**
+ * Resizes the given [0;1] float list as per unstable MSC3246 spec
+ * to a [0;1024] int list to be used for waveform rendering.
+ *
+ * https://github.com/matrix-org/matrix-spec-proposals/blob/travis/msc/audio-waveform/proposals/3246-audio-waveform.md
+ */
+internal fun List<Float>.toMSC3246range(): List<UShort> = map { (it * 1024).toInt().toUShort() }

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/room/RustMatrixRoom.kt

@@ -46,6 +46,7 @@ import io.element.android.libraries.matrix.api.widget.MatrixWidgetSettings
 import io.element.android.libraries.matrix.impl.core.toProgressWatcher
 import io.element.android.libraries.matrix.impl.media.MediaUploadHandlerImpl
 import io.element.android.libraries.matrix.impl.media.map
+import io.element.android.libraries.matrix.impl.media.toMSC3246range
 import io.element.android.libraries.matrix.impl.notificationsettings.RustNotificationSettingsService
 import io.element.android.libraries.matrix.impl.poll.toInner
 import io.element.android.libraries.matrix.impl.room.location.toInner
@@ -499,13 +500,13 @@ class RustMatrixRoom(
     override suspend fun sendVoiceMessage(
         file: File,
         audioInfo: AudioInfo,
-        waveform: List<Int>,
+        waveform: List<Float>,
         progressCallback: ProgressCallback?,
     ): Result<MediaUploadHandler> = sendAttachment(listOf(file)) {
         innerRoom.sendVoiceMessage(
             url = file.path,
             audioInfo = audioInfo.map(),
-            waveform = waveform.map { it.toUShort() },
+            waveform = waveform.toMSC3246range(),
             progressWatcher = progressCallback?.toProgressWatcher(),
         )
     }

libraries/matrix/test/src/main/kotlin/io/element/android/libraries/matrix/test/room/FakeMatrixRoom.kt

@@ -387,7 +387,7 @@ class FakeMatrixRoom(
     override suspend fun sendVoiceMessage(
         file: File,
         audioInfo: AudioInfo,
-        waveform: List<Int>,
+        waveform: List<Float>,
         progressCallback: ProgressCallback?
     ): Result<MediaUploadHandler> = fakeSendMedia(progressCallback)
 

libraries/mediaupload/api/src/main/kotlin/io/element/android/libraries/mediaupload/api/MediaSender.kt

@@ -55,7 +55,7 @@ class MediaSender @Inject constructor(
     suspend fun sendVoiceMessage(
         uri: Uri,
         mimeType: String,
-        waveForm: List<Int>,
+        waveForm: List<Float>,
         progressCallback: ProgressCallback? = null
     ): Result<Unit> {
         return preProcessor

libraries/mediaupload/api/src/main/kotlin/io/element/android/libraries/mediaupload/api/MediaUploadInfo.kt

@@ -29,6 +29,6 @@ sealed interface MediaUploadInfo {
     data class Image(override val file: File, val imageInfo: ImageInfo, val thumbnailFile: File) : MediaUploadInfo
     data class Video(override val file: File, val videoInfo: VideoInfo, val thumbnailFile: File) : MediaUploadInfo
     data class Audio(override val file: File, val audioInfo: AudioInfo) : MediaUploadInfo
-    data class VoiceMessage(override val file: File, val audioInfo: AudioInfo, val waveform: List<Int>) : MediaUploadInfo
+    data class VoiceMessage(override val file: File, val audioInfo: AudioInfo, val waveform: List<Float>) : MediaUploadInfo
     data class AnyFile(override val file: File, val fileInfo: FileInfo) : MediaUploadInfo
 }