Media transfers (#440)

* tor voice wip * worky BLE a bit * can send sound * remove tor * ui cleanup * recording time * progress bar color * nicknames for audio * onboarding permissions no microphone * may work * fix destionation * extend * refactor voice input component * fix keyboard collapse issue * send images * wip image open * image sending works * wip waveforms * better * better animation * fix cursor for sending audio * image sending animation * image sending animation * full screen image viewer * gossip sync for fragments too * reduce delays * fix keyboard focus * use v2 for file transfers * do not sync fragments * scrollable image viewer * ui * ui adjustments * nicer animation * seek through audio * add spec * add more details to documentation * File sharing E2E: - Add TLV BitchatFilePacket, FileSharingManager - Implement sendFileNote in ChatViewModel - File receive path: save to files/incoming and render [file] messages with FileMessageItem or FileSendingAnimation during transfer - SAF FilePickerButton and dispatcher wiring; image/file choice to follow in MediaPickerOptions - Add FileViewerDialog with system open/save, FileProvider and file_paths - Hook transfer progress to file sending UI - Manifest: READ_MEDIA_* and FileProvider - Fix MessageHandler saving and prefix for non-image payloads - Add helper utils (FileUtils) * kinda wip * fix buttons * files half working * wip file transfer * file packet has 2-byte TLV and chunks. it wokrs but it sucks * clean * remove gossip sync for fragments * fix audio and image rendering * adjust FILE_SIZE TLV size too * cleanup * haptic * private messages media * read receipts for media * use enum for message type not string * delivery ack checks dont push content * check * animation fix * refactor * ui adjustments * comments * refactor * fix crash on send and receive of the same file * refactor notifications * tests
2026-07-25 10:25:19 +00:00 · 2025-09-19 22:46:14 +02:00
parent 1178fc254a
commit 633a506753
57 changed files with 4801 additions and 138 deletions
@@ -0,0 +1,274 @@
+package com.bitchat.android.features.file
+
+import android.content.Context
+import android.net.Uri
+import android.os.Environment
+import android.util.Log
+import androidx.core.content.FileProvider
+import java.io.File
+import java.io.FileOutputStream
+import java.io.InputStream
+import java.text.SimpleDateFormat
+import java.util.*
+
+object FileUtils {
+
+    private const val TAG = "FileUtils"
+
+    /**
+     * Save a file from URI to app's file directory with unique filename
+     */
+    fun saveFileFromUri(
+        context: Context,
+        uri: Uri,
+        originalName: String? = null
+    ): String? {
+        return try {
+            val inputStream = context.contentResolver.openInputStream(uri)
+            if (inputStream == null) {
+                Log.e(TAG, "❌ Failed to open input stream for URI: $uri")
+                return null
+            }
+            Log.d(TAG, "📂 Opened input stream successfully")
+
+            // Determine file extension
+            val extension = originalName?.substringAfterLast(".") ?: "bin"
+            val fileName = "file_${System.currentTimeMillis()}.$extension"
+
+            // Create incoming dir if needed
+            val incomingDir = File(context.filesDir, "files/incoming").apply {
+                if (!exists()) mkdirs()
+            }
+
+            val file = File(incomingDir, fileName)
+
+            inputStream.use { input ->
+                FileOutputStream(file).use { output ->
+                    input.copyTo(output)
+                }
+            }
+
+            Log.d(TAG, "Saved file to: ${file.absolutePath}")
+            file.absolutePath
+
+        } catch (e: Exception) {
+            Log.e(TAG, "Failed to save file from URI", e)
+            null
+        }
+    }
+
+    /**
+     * Copy file to app's outgoing directory for sending
+     */
+    fun copyFileForSending(context: Context, uri: Uri, originalName: String? = null): String? {
+        Log.d(TAG, "🔄 Starting file copy from URI: $uri")
+        return try {
+            val inputStream = context.contentResolver.openInputStream(uri)
+            if (inputStream == null) {
+                Log.e(TAG, "❌ Failed to open input stream for URI: $uri")
+                return null
+            }
+            Log.d(TAG, "📂 Opened input stream successfully")
+
+            // Determine original filename and extension if available
+            val displayName = originalName ?: run {
+                try {
+                    context.contentResolver.query(uri, null, null, null, null)?.use { cursor ->
+                        val nameIndex = cursor.getColumnIndex(android.provider.MediaStore.MediaColumns.DISPLAY_NAME)
+                        if (nameIndex >= 0 && cursor.moveToFirst()) cursor.getString(nameIndex) else null
+                    }
+                } catch (_: Exception) { null }
+            }
+            val extension = displayName?.substringAfterLast('.', missingDelimiterValue = "")?.takeIf { it.isNotBlank() }
+                ?: run {
+                    // Try mime type to extension
+                    val mime = try { context.contentResolver.getType(uri) } catch (_: Exception) { null }
+                    android.webkit.MimeTypeMap.getSingleton().getExtensionFromMimeType(mime) ?: "bin"
+                }
+            // Preserve original filename (without artificial prefixes), ensure uniqueness
+            val baseName = displayName?.substringBeforeLast('.')?.take(64)?.replace(Regex("[^A-Za-z0-9._-]"), "_")
+                ?: "file"
+            var fileName = if (extension.isNotBlank()) "$baseName.$extension" else baseName
+
+            // Create outgoing dir if needed
+            val outgoingDir = File(context.filesDir, "files/outgoing").apply {
+                if (!exists()) mkdirs()
+            }
+
+            var target = File(outgoingDir, fileName)
+            if (target.exists()) {
+                var idx = 1
+                val pureBase = baseName
+                val dotExt = if (extension.isNotBlank()) ".${extension}" else ""
+                while (target.exists() && idx < 1000) {
+                    fileName = "$pureBase ($idx)$dotExt"
+                    target = File(outgoingDir, fileName)
+                    idx++
+                }
+            }
+
+            inputStream.use { input ->
+                FileOutputStream(target).use { output ->
+                    input.copyTo(output)
+                }
+            }
+
+            Log.d(TAG, "✅ Successfully copied file for sending: ${target.absolutePath}")
+            Log.d(TAG, "📊 Final file size: ${target.length()} bytes")
+            target.absolutePath
+
+        } catch (e: Exception) {
+            Log.e(TAG, "❌ CRITICAL: Failed to copy file for sending", e)
+            Log.e(TAG, "❌ Source URI: $uri")
+            Log.e(TAG, "❌ Original name: $originalName")
+            Log.e(TAG, "❌ Error type: ${e.javaClass.simpleName}")
+            null
+        }
+    }
+
+    /**
+     * Get MIME type for a file based on extension
+     */
+    fun getMimeTypeFromExtension(fileName: String): String {
+        return when (fileName.substringAfterLast(".", "").lowercase()) {
+            "pdf" -> "application/pdf"
+            "doc" -> "application/msword"
+            "docx" -> "application/vnd.openxmlformats-officedocument.wordprocessingml.document"
+            "xls" -> "application/vnd.ms-excel"
+            "xlsx" -> "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
+            "ppt" -> "application/vnd.ms-powerpoint"
+            "pptx" -> "application/vnd.openxmlformats-officedocument.presentationml.presentation"
+            "txt" -> "text/plain"
+            "json" -> "application/json"
+            "xml" -> "application/xml"
+            "csv" -> "text/csv"
+            "html", "htm" -> "text/html"
+            "jpg", "jpeg" -> "image/jpeg"
+            "png" -> "image/png"
+            "gif" -> "image/gif"
+            "bmp" -> "image/bmp"
+            "webp" -> "image/webp"
+            "svg" -> "image/svg+xml"
+            "mp3" -> "audio/mpeg"
+            "wav" -> "audio/wav"
+            "m4a" -> "audio/mp4"
+            "mp4" -> "video/mp4"
+            "avi" -> "video/x-msvideo"
+            "mov" -> "video/quicktime"
+            "zip" -> "application/zip"
+            "rar" -> "application/vnd.rar"
+            "7z" -> "application/x-7z-compressed"
+            else -> "application/octet-stream"
+        }
+    }
+
+    /**
+     * Format file size for display
+     */
+    fun formatFileSize(bytes: Long): String {
+        val units = arrayOf("B", "KB", "MB", "GB")
+        var size = bytes.toDouble()
+        var unitIndex = 0
+        while (size >= 1024 && unitIndex < units.size - 1) {
+            size /= 1024.0
+            unitIndex++
+        }
+        return "%.1f %s".format(size, units[unitIndex])
+    }
+
+    /**
+     * Check if file is viewable in system viewer
+     */
+    fun isFileViewable(fileName: String): Boolean {
+        val extension = fileName.substringAfterLast(".", "").lowercase()
+        return extension in listOf(
+            "pdf", "txt", "json", "xml", "html", "htm", "csv",
+            "jpg", "jpeg", "png", "gif", "bmp", "webp", "svg"
+        )
+    }
+
+    /**
+     * Save an incoming file packet to app storage and return absolute path.
+     * Mirrors existing behavior used in MessageHandler (preserves names and folders).
+     */
+    fun saveIncomingFile(
+        context: Context,
+        file: com.bitchat.android.model.BitchatFilePacket
+    ): String {
+        val lowerMime = file.mimeType.lowercase()
+        val isImage = lowerMime.startsWith("image/")
+        val baseDir = context.filesDir
+        val subdir = if (isImage) "images/incoming" else "files/incoming"
+        val dir = java.io.File(baseDir, subdir).apply { mkdirs() }
+
+        fun extFromMime(m: String): String = when (m.lowercase()) {
+            "image/jpeg", "image/jpg" -> ".jpg"
+            "image/png" -> ".png"
+            "image/webp" -> ".webp"
+            "application/pdf" -> ".pdf"
+            "text/plain" -> ".txt"
+            else -> if (isImage) ".jpg" else ".bin"
+        }
+
+        // Prefer transmitted original name; ensure uniqueness to avoid overwrites
+        val baseName = (file.fileName.takeIf { it.isNotBlank() }
+            ?: (if (isImage) "img" else "file"))
+            .replace(Regex("[^A-Za-z0-9._-]"), "_")
+        val ext = extFromMime(lowerMime)
+        var safeName = if (baseName.contains('.')) baseName else baseName + ext
+        var idx = 1
+        while (java.io.File(dir, safeName).exists() && idx < 1000) {
+            val dot = safeName.lastIndexOf('.')
+            safeName = if (dot > 0) {
+                val b = safeName.substring(0, dot)
+                val e = safeName.substring(dot)
+                "$b ($idx)$e"
+            } else {
+                "$safeName ($idx)"
+            }
+            idx++
+        }
+
+        return try {
+            val out = java.io.File(dir, safeName)
+            out.outputStream().use { it.write(file.content) }
+            out.absolutePath
+        } catch (_: Exception) {
+            // Fallback to cache dir with uniqueness
+            try {
+                var fallback = safeName
+                var idx2 = 1
+                while (java.io.File(context.cacheDir, fallback).exists() && idx2 < 1000) {
+                    val dot = fallback.lastIndexOf('.')
+                    fallback = if (dot > 0) {
+                        val b = fallback.substring(0, dot)
+                        val e = fallback.substring(dot)
+                        "$b ($idx2)$e"
+                    } else {
+                        "$fallback ($idx2)"
+                    }
+                    idx2++
+                }
+                val out = java.io.File(context.cacheDir, fallback)
+                out.outputStream().use { it.write(file.content) }
+                out.absolutePath
+            } catch (_: Exception) {
+                val tmp = java.io.File.createTempFile(if (isImage) "img_" else "file_", if (isImage) ".jpg" else ".bin")
+                tmp.writeBytes(file.content)
+                tmp.absolutePath
+            }
+        }
+    }
+
+    /**
+     * Classify BitchatMessageType from MIME string used in file messages.
+     */
+    fun messageTypeForMime(mime: String): com.bitchat.android.model.BitchatMessageType {
+        val lower = mime.lowercase()
+        return when {
+            lower.startsWith("image/") -> com.bitchat.android.model.BitchatMessageType.Image
+            lower.startsWith("audio/") -> com.bitchat.android.model.BitchatMessageType.Audio
+            else -> com.bitchat.android.model.BitchatMessageType.File
+        }
+    }
+}
@@ -0,0 +1,36 @@
+package com.bitchat.android.features.media
+
+import android.content.Context
+import android.graphics.Bitmap
+import android.graphics.BitmapFactory
+import java.io.File
+import java.io.FileOutputStream
+
+object ImageUtils {
+    fun downscaleAndSaveToAppFiles(context: Context, uri: android.net.Uri, maxDim: Int = 512, quality: Int = 85): String? {
+        return try {
+            val resolver = context.contentResolver
+            val input = resolver.openInputStream(uri) ?: return null
+            val original = BitmapFactory.decodeStream(input)
+            input.close()
+            original ?: return null
+            val w = original.width
+            val h = original.height
+            val scale = (maxOf(w, h).toFloat() / maxDim.toFloat()).coerceAtLeast(1f)
+            val newW = (w / scale).toInt().coerceAtLeast(1)
+            val newH = (h / scale).toInt().coerceAtLeast(1)
+            val scaled = if (scale > 1f) Bitmap.createScaledBitmap(original, newW, newH, true) else original
+            val dir = File(context.filesDir, "images/outgoing").apply { mkdirs() }
+            val outFile = File(dir, "img_${System.currentTimeMillis()}.jpg")
+            FileOutputStream(outFile).use { fos ->
+                scaled.compress(Bitmap.CompressFormat.JPEG, quality, fos)
+            }
+            if (scaled !== original) try { original.recycle() } catch (_: Exception) {}
+            try { if (scaled != original) scaled.recycle() } catch (_: Exception) {}
+            outFile.absolutePath
+        } catch (e: Exception) {
+            null
+        }
+    }
+}
+
@@ -0,0 +1,76 @@
+package com.bitchat.android.features.voice
+
+import android.content.Context
+import android.media.MediaRecorder
+import android.util.Log
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.withContext
+import java.io.File
+import java.text.SimpleDateFormat
+import java.util.Date
+import java.util.Locale
+
+/**
+ * Simple MediaRecorder wrapper that records to M4A (AAC) for wide compatibility.
+ * The resulting file has MIME audio/mp4.
+ */
+class VoiceRecorder(private val context: Context) {
+    companion object { private const val TAG = "VoiceRecorder" }
+
+    private var recorder: MediaRecorder? = null
+    private val _amplitude = MutableStateFlow(0)
+    val amplitude: StateFlow<Int> = _amplitude.asStateFlow()
+
+    private var outFile: File? = null
+
+    fun start(): File? {
+        stop() // ensure previous session closed
+        return try {
+            val dir = File(context.filesDir, "voicenotes/outgoing").apply { mkdirs() }
+            val name = "voice_" + SimpleDateFormat("yyyyMMdd_HHmmss", Locale.US).format(Date()) + ".m4a"
+            val file = File(dir, name)
+            val rec = MediaRecorder()
+            rec.setAudioSource(MediaRecorder.AudioSource.MIC)
+            rec.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4)
+            rec.setAudioEncoder(MediaRecorder.AudioEncoder.AAC)
+            rec.setAudioChannels(1)
+            rec.setAudioSamplingRate(44100)
+            // Lower bitrate to keep BLE payloads <= 32KiB for fragmentation
+            rec.setAudioEncodingBitRate(32_000)
+            rec.setOutputFile(file.absolutePath)
+            rec.prepare()
+            rec.start()
+            recorder = rec
+            outFile = file
+            file
+        } catch (e: Exception) {
+            Log.e(TAG, "Failed to start recording: ${e.message}")
+            null
+        }
+    }
+
+    fun pollAmplitude(): Int {
+        return try {
+            val amp = recorder?.maxAmplitude ?: 0
+            _amplitude.value = amp
+            amp
+        } catch (_: Exception) { 0 }
+    }
+
+    fun stop(): File? {
+        try {
+            recorder?.apply {
+                try { stop() } catch (_: Exception) {}
+                try { reset() } catch (_: Exception) {}
+                try { release() } catch (_: Exception) {}
+            }
+        } catch (_: Exception) {}
+        val f = outFile
+        recorder = null
+        outFile = null
+        return f
+    }
+}
@@ -0,0 +1,42 @@
+package com.bitchat.android.features.voice
+
+import androidx.compose.animation.core.LinearEasing
+import androidx.compose.animation.core.animateFloatAsState
+import androidx.compose.animation.core.tween
+import androidx.compose.foundation.Canvas
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.drawscope.drawIntoCanvas
+import androidx.compose.ui.unit.dp
+import kotlin.math.min
+
+@Composable
+fun CyberpunkVisualizer(amplitude: Int, color: Color, modifier: Modifier = Modifier) {
+    val norm = min(1f, amplitude / 20_000f)
+    val heightFrac by animateFloatAsState(
+        targetValue = 0.1f + 0.9f * norm,
+        animationSpec = tween(120, easing = LinearEasing), label = "amp"
+    )
+    Canvas(
+        modifier = modifier
+            .fillMaxWidth()
+            .height(48.dp)
+    ) {
+        val w = size.width
+        val h = size.height
+        val barCount = 24
+        val gap = 6f
+        val bw = (w - gap * (barCount - 1)) / barCount
+        for (i in 0 until barCount) {
+            val phase = (i.toFloat() / barCount)
+            val barH = (0.2f + heightFrac * (0.8f * (0.5f + 0.5f * kotlin.math.sin(phase * Math.PI * 2).toFloat()))) * h
+            val x = i * (bw + gap)
+            val y = (h - barH) / 2f
+            drawRect(color.copy(alpha = 0.85f), topLeft = androidx.compose.ui.geometry.Offset(x, y), size = androidx.compose.ui.geometry.Size(bw, barH))
+        }
+    }
+}
@@ -0,0 +1,174 @@
+package com.bitchat.android.features.voice
+
+import android.media.MediaCodec
+import android.media.MediaExtractor
+import android.media.MediaFormat
+import android.util.Log
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.launch
+import java.nio.ByteBuffer
+import java.nio.ByteOrder
+import java.util.concurrent.ConcurrentHashMap
+import kotlin.math.abs
+import kotlin.math.ln
+import kotlin.math.max
+import kotlin.math.min
+
+object VoiceWaveformCache {
+    private val map = ConcurrentHashMap<String, FloatArray>()
+    fun put(path: String, samples: FloatArray) { map[path] = samples }
+    fun get(path: String): FloatArray? = map[path]
+}
+
+fun normalizeAmplitudeSample(amp: Int): Float {
+    val a = max(0, amp)
+    val norm = ln(1.0 + a.toDouble()) / ln(1.0 + 32768.0)
+    return norm.toFloat().coerceIn(0f, 1f)
+}
+
+fun resampleWave(values: FloatArray, target: Int): FloatArray {
+    if (values.isEmpty() || target <= 0) return FloatArray(target) { 0f }
+    if (values.size == target) return values
+    val out = FloatArray(target)
+    val step = (values.size - 1).toFloat() / (target - 1).toFloat()
+    var x = 0f
+    for (i in 0 until target) {
+        val idx = x.toInt()
+        val frac = x - idx
+        val a = values[idx]
+        val b = values[min(values.size - 1, idx + 1)]
+        out[i] = (a + (b - a) * frac).coerceIn(0f, 1f)
+        x += step
+    }
+    return out
+}
+
+object AudioWaveformExtractor {
+    private val scope = CoroutineScope(Dispatchers.IO + SupervisorJob())
+
+    fun extractAsync(path: String, sampleCount: Int = 120, onComplete: (FloatArray?) -> Unit) {
+        scope.launch {
+            onComplete(runCatching { extract(path, sampleCount) }.getOrNull())
+        }
+    }
+
+    private fun extract(path: String, sampleCount: Int): FloatArray? {
+        val extractor = MediaExtractor()
+        extractor.setDataSource(path)
+        val trackIndex = (0 until extractor.trackCount).firstOrNull { idx ->
+            val fmt = extractor.getTrackFormat(idx)
+            val mime = fmt.getString(MediaFormat.KEY_MIME) ?: ""
+            mime.startsWith("audio/")
+        } ?: return null
+        extractor.selectTrack(trackIndex)
+        val format = extractor.getTrackFormat(trackIndex)
+        val mime = format.getString(MediaFormat.KEY_MIME) ?: return null
+        val codec = MediaCodec.createDecoderByType(mime)
+        codec.configure(format, null, null, 0)
+        codec.start()
+
+        val durationUs = if (format.containsKey(MediaFormat.KEY_DURATION)) format.getLong(MediaFormat.KEY_DURATION) else 0L
+        val desiredBins = sampleCount.coerceAtLeast(32)
+        val bins = FloatArray(desiredBins) { 0f }
+        val counts = IntArray(desiredBins) { 0 }
+
+        val inBuffers = codec.inputBuffers
+        val outInfo = MediaCodec.BufferInfo()
+
+        var sawEOS = false
+        while (!sawEOS) {
+            // Queue input
+            val inIndex = codec.dequeueInputBuffer(10_000)
+            if (inIndex >= 0) {
+                val buffer = codec.getInputBuffer(inIndex) ?: inBuffers[inIndex]
+                val sampleSize = extractor.readSampleData(buffer, 0)
+                if (sampleSize < 0) {
+                    codec.queueInputBuffer(inIndex, 0, 0, 0L, MediaCodec.BUFFER_FLAG_END_OF_STREAM)
+                } else {
+                    val presentationTimeUs = extractor.sampleTime
+                    codec.queueInputBuffer(inIndex, 0, sampleSize, presentationTimeUs, 0)
+                    extractor.advance()
+                }
+            }
+
+            // Dequeue output
+            var outIndex = codec.dequeueOutputBuffer(outInfo, 10_000)
+            while (outIndex >= 0) {
+                val outBuf = codec.getOutputBuffer(outIndex)
+                if (outBuf != null && outInfo.size > 0) {
+                    outBuf.order(ByteOrder.LITTLE_ENDIAN)
+                    val shortCount = outInfo.size / 2
+                    val shorts = ShortArray(shortCount)
+                    outBuf.asShortBuffer().get(shorts)
+
+                    // Map this buffer to bins using timestamp range
+                    val startUs = outInfo.presentationTimeUs
+                    val endUs = startUs + bufferDurationUs(format, outInfo.size)
+                    val startBin = binForTime(startUs, durationUs, desiredBins)
+                    val endBin = binForTime(endUs, durationUs, desiredBins).coerceAtMost(desiredBins - 1)
+
+                    var idx = 0
+                    for (bin in startBin..endBin) {
+                        // aggregate portion of buffer to this bin
+                        val window = shorts.size / max(1, (endBin - startBin + 1))
+                        val begin = idx
+                        val finish = min(shorts.size, idx + window)
+                        var acc = 0.0
+                        var cnt = 0
+                        for (i in begin until finish) {
+                            acc += abs(shorts[i].toInt())
+                            cnt += 1
+                        }
+                        val avg = if (cnt > 0) (acc / cnt) else 0.0
+                        val norm = (avg / 32768.0).coerceIn(0.0, 1.0).toFloat()
+                        bins[bin] = max(bins[bin], norm)
+                        counts[bin] += 1
+                        idx += window
+                    }
+                }
+                codec.releaseOutputBuffer(outIndex, false)
+                outIndex = codec.dequeueOutputBuffer(outInfo, 0)
+            }
+
+            if (outInfo.flags and MediaCodec.BUFFER_FLAG_END_OF_STREAM != 0) {
+                sawEOS = true
+            }
+        }
+
+        codec.stop()
+        codec.release()
+        extractor.release()
+
+        // Smooth + normalize
+        var maxVal = 0f
+        for (i in bins.indices) {
+            if (counts[i] == 0) continue
+            maxVal = max(maxVal, bins[i])
+        }
+        if (maxVal <= 0f) maxVal = 1f
+        for (i in bins.indices) {
+            bins[i] = (bins[i] / maxVal).coerceIn(0f, 1f)
+        }
+
+        return bins
+    }
+
+    private fun bufferDurationUs(format: MediaFormat, bytes: Int): Long {
+        return try {
+            val sampleRate = format.getInteger(MediaFormat.KEY_SAMPLE_RATE)
+            val channels = format.getInteger(MediaFormat.KEY_CHANNEL_COUNT)
+            val samples = bytes / 2 / max(1, channels)
+            (samples * 1_000_000L) / max(1, sampleRate)
+        } catch (e: Exception) {
+            0L
+        }
+    }
+
+    private fun binForTime(presentationUs: Long, durationUs: Long, bins: Int): Int {
+        if (durationUs <= 0L) return 0
+        val frac = presentationUs.toDouble() / durationUs.toDouble()
+        return (frac * bins).toInt().coerceIn(0, bins - 1)
+    }
+}