Implement in-app playback with ffmpeg frame pump and Go audio

go.mod

@@ -4,13 +4,12 @@ go 1.25.1
 
 require (
 	fyne.io/fyne/v2 v2.7.1
-	github.com/u2takey/ffmpeg-go v0.5.0
+	github.com/hajimehoshi/oto v0.7.1
 )
 
 require (
 	fyne.io/systray v1.11.1-0.20250603113521-ca66a66d8b58 // indirect
 	github.com/BurntSushi/toml v1.5.0 // indirect
-	github.com/aws/aws-sdk-go v1.38.20 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/fredbi/uri v1.1.1 // indirect
 	github.com/fsnotify/fsnotify v1.9.0 // indirect
@@ -26,7 +25,6 @@ require (
 	github.com/hack-pad/go-indexeddb v0.3.2 // indirect
 	github.com/hack-pad/safejs v0.1.0 // indirect
 	github.com/jeandeaual/go-locale v0.0.0-20250612000132-0ef82f21eade // indirect
-	github.com/jmespath/go-jmespath v0.4.0 // indirect
 	github.com/jsummers/gobmp v0.0.0-20230614200233-a9de23ed2e25 // indirect
 	github.com/kr/text v0.2.0 // indirect
 	github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646 // indirect
@@ -36,9 +34,10 @@ require (
 	github.com/srwiley/oksvg v0.0.0-20221011165216-be6e8873101c // indirect
 	github.com/srwiley/rasterx v0.0.0-20220730225603-2ab79fcdd4ef // indirect
 	github.com/stretchr/testify v1.11.1 // indirect
-	github.com/u2takey/go-utils v0.3.1 // indirect
 	github.com/yuin/goldmark v1.7.8 // indirect
+	golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8 // indirect
 	golang.org/x/image v0.24.0 // indirect
+	golang.org/x/mobile v0.0.0-20231127183840-76ac6878050a // indirect
 	golang.org/x/net v0.35.0 // indirect
 	golang.org/x/sys v0.30.0 // indirect
 	golang.org/x/text v0.22.0 // indirect

go.sum

@@ -39,6 +39,8 @@ github.com/hack-pad/go-indexeddb v0.3.2 h1:DTqeJJYc1usa45Q5r52t01KhvlSN02+Oq+tQb
 github.com/hack-pad/go-indexeddb v0.3.2/go.mod h1:QvfTevpDVlkfomY498LhstjwbPW6QC4VC/lxYb0Kom0=
 github.com/hack-pad/safejs v0.1.0 h1:qPS6vjreAqh2amUqj4WNG1zIw7qlRQJ9K10eDKMCnE8=
 github.com/hack-pad/safejs v0.1.0/go.mod h1:HdS+bKF1NrE72VoXZeWzxFOVQVUSqZJAG0xNCnb+Tio=
+github.com/hajimehoshi/oto v0.7.1 h1:I7maFPz5MBCwiutOrz++DLdbr4rTzBsbBuV2VpgU9kk=
+github.com/hajimehoshi/oto v0.7.1/go.mod h1:wovJ8WWMfFKvP587mhHgot/MBr4DnNy9m6EepeVGnos=
 github.com/jeandeaual/go-locale v0.0.0-20250612000132-0ef82f21eade h1:FmusiCI1wHw+XQbvL9M+1r/C3SPqKrmBaIOYwVfQoDE=
 github.com/jeandeaual/go-locale v0.0.0-20250612000132-0ef82f21eade/go.mod h1:ZDXo8KHryOWSIqnsb/CiDq7hQUYryCgdVnxbj8tDG7o=
 github.com/jsummers/gobmp v0.0.0-20230614200233-a9de23ed2e25 h1:YLvr1eE6cdCqjOe972w/cYF+FjW34v27+9Vo5106B4M=
@@ -65,12 +67,21 @@ github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu
 github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
 github.com/yuin/goldmark v1.7.8 h1:iERMLn0/QJeHFhxSt3p6PeN9mGnvIKSpG9YYorDMnic=
 github.com/yuin/goldmark v1.7.8/go.mod h1:uzxRWxtg69N339t3louHJ7+O03ezfj6PlliRlaOzY1E=
+golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8 h1:idBdZTd9UioThJp8KpM/rTSinK/ChZFBE43/WtIy8zg=
+golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
+golang.org/x/image v0.0.0-20190227222117-0694c2d4d067/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js=
 golang.org/x/image v0.24.0 h1:AN7zRgVsbvmTfNyqIbbOraYL8mSwcKncEj8ofjgzcMQ=
 golang.org/x/image v0.24.0/go.mod h1:4b/ITuLfqYq1hqZcjofwctIhi7sZh2WaCjvsBNjjya8=
+golang.org/x/mobile v0.0.0-20190415191353-3e0bab5405d6/go.mod h1:E/iHnbuqvinMTCcRqshq8CkpyQDoeVncDDYHnLhea+o=
+golang.org/x/mobile v0.0.0-20231127183840-76ac6878050a h1:sYbmY3FwUWCBTodZL1S3JUuOvaW6kM2o+clDzzDNBWg=
+golang.org/x/mobile v0.0.0-20231127183840-76ac6878050a/go.mod h1:Ede7gF0KGoHlj822RtphAHK1jLdrcuRBZg0sF1Q+SPc=
 golang.org/x/net v0.35.0 h1:T5GQRQb2y08kTAByq9L4/bz8cipCdA8FbRTXewonqY8=
 golang.org/x/net v0.35.0/go.mod h1:EglIi67kWsHKlRzzVMUD93VMSWGFOMSZgxFjparz1Qk=
+golang.org/x/sys v0.0.0-20190312061237-fead79001313/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190429190828-d89cdac9e872/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
 golang.org/x/sys v0.30.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.22.0 h1:bofq7m3/HAFvbF51jz3Q9wLg3jkvSPuiZu/pD1XwgtM=
 golang.org/x/text v0.22.0/go.mod h1:YRoo4H8PVmsu+E3Ou7cqLVH8oXWIHVoX0jqUWALQhfY=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
@@ -78,57 +89,3 @@ gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f h1:BLraFXnmrev5lT+xlilqcH8X
 gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-github.com/aws/aws-sdk-go v1.38.20 h1:QbzNx/tdfATbdKfubBpkt84OM6oBkxQZRw6+bW2GyeA=
-github.com/aws/aws-sdk-go v1.38.20/go.mod h1:hcU610XS61/+aQV88ixoOzUoG7v3b31pl2zKMmprdro=
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/disintegration/imaging v1.6.2/go.mod h1:44/5580QXChDfwIclfc/PCwrr44amcmDAg8hxG0Ewe4=
-github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
-github.com/go-logr/logr v0.1.0/go.mod h1:ixOQHD9gLJUVQQ2ZOR7zLEifBX6tGkNJF4QyIY7sIas=
-github.com/gogo/protobuf v1.3.1/go.mod h1:SlYgWuQ5SjCEi6WLHjHCa1yvBfUnHcTbrrZtXPKa29o=
-github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
-github.com/google/uuid v1.1.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
-github.com/hashicorp/golang-lru v0.5.4/go.mod h1:iADmTwqILo4mZ8BN3D2Q6+9jd8WM5uGBxy+E8yxSoD4=
-github.com/jmespath/go-jmespath v0.4.0 h1:BEgLn5cpjn8UN1mAw4NjwDrS35OdebyEtFe+9YPoQUg=
-github.com/jmespath/go-jmespath v0.4.0/go.mod h1:T8mJZnbsbmF+m6zOOFylbeCJqk5+pHWvzYPizyZiYoo=
-github.com/jmespath/go-jmespath/internal/testify v1.5.1 h1:shLQSRRSCCPj3f2gpwzGwWFoC7ycTf1rcQZHOlsJ6N8=
-github.com/jmespath/go-jmespath/internal/testify v1.5.1/go.mod h1:L3OGu8Wl2/fWfCI6z80xFu9LTZmf1ZRjMHUOPmWr69U=
-github.com/json-iterator/go v1.1.10/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
-github.com/kisielk/errcheck v1.2.0/go.mod h1:/BMXB+zMLi60iA8Vv6Ksmxu/1UDYcXs4uQLJ+jE2L00=
-github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
-github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
-github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
-github.com/modern-go/reflect2 v0.0.0-20180701023420-4b7aa43c6742/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=
-github.com/modern-go/reflect2 v1.0.1/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=
-github.com/panjf2000/ants/v2 v2.4.2/go.mod h1:f6F0NZVFsGCp5A7QW/Zj/m92atWwOkY0OIhFxRNFr4A=
-github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
-github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
-github.com/spf13/afero v1.2.2/go.mod h1:9ZxEEn6pIJ8Rxe320qSDBk6AsU0r9pR7Q4OcevTdifk=
-github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
-github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
-github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
-github.com/u2takey/ffmpeg-go v0.5.0 h1:r7d86XuL7uLWJ5mzSeQ03uvjfIhiJYvsRAJFCW4uklU=
-github.com/u2takey/ffmpeg-go v0.5.0/go.mod h1:ruZWkvC1FEiUNjmROowOAps3ZcWxEiOpFoHCvk97kGc=
-github.com/u2takey/go-utils v0.3.1 h1:TaQTgmEZZeDHQFYfd+AdUT1cT4QJgJn/XVPELhHw4ys=
-github.com/u2takey/go-utils v0.3.1/go.mod h1:6e+v5vEZ/6gu12w/DC2ixZdZtCrNokVxD0JUklcqdCs=
-gocv.io/x/gocv v0.25.0/go.mod h1:Rar2PS6DV+T4FL+PM535EImD/h13hGVaHhnCu1xarBs=
-golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
-golang.org/x/image v0.0.0-20191009234506-e7c1f5e7dbb8/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
-golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/net v0.0.0-20201110031124-69a78807bb2b/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
-golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20200602225109-6fdc65e7d980/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
-golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/time v0.0.0-20190308202827-9d24e82272b4/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
-golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/tools v0.0.0-20181030221726-6c7e314b6563/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
-gopkg.in/yaml.v2 v2.2.7/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
-gopkg.in/yaml.v2 v2.2.8 h1:obN1ZagJSUGI0Ek/LBmuj4SNLPfIny3KsKFopxRdj10=
-gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
-sigs.k8s.io/yaml v1.2.0/go.mod h1:yfXDCHCao9+ENCvLSE62v9VSji2MKu5jeNfTrofGhJc=

main.go

@@ -6,8 +6,10 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
+	"image"
 	"image/color"
 	"image/png"
+	"io"
 	"log"
 	"math"
 	"os"
@@ -16,6 +18,7 @@ import (
 	"slices"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 
 	"fyne.io/fyne/v2"
@@ -28,6 +31,7 @@ import (
 	"fyne.io/fyne/v2/theme"
 	"fyne.io/fyne/v2/widget"
 	"git.leaktechnologies.dev/stu/VideoTools/internal/player"
+	"github.com/hajimehoshi/oto"
 )
 
 // Module describes a high level tool surface that gets a tile on the menu.
@@ -129,6 +133,7 @@ type appState struct {
 	playerMuted  bool
 	lastVolume   float64
 	playerPaused bool
+	playSess     *playSession
 }
 
 func (s *appState) stopPreview() {
@@ -212,6 +217,10 @@ func (s *appState) shutdown() {
 }
 
 func (s *appState) stopPlayer() {
+	if s.playSess != nil {
+		s.playSess.Stop()
+		s.playSess = nil
+	}
 	if s.player != nil {
 		s.player.Stop()
 	}
@@ -870,18 +879,43 @@ func buildVideoPane(state *appState, min fyne.Size, src *videoSource, onCover fu
 		dlg.Show()
 	})
 
-	usePlayer := state.playerReady && state.player != nil
+	usePlayer := true
 
 	currentTime := widget.NewLabel("0:00")
 	totalTime := widget.NewLabel(src.DurationString())
 	totalTime.Alignment = fyne.TextAlignTrailing
+	var updatingProgress bool
+	slider := widget.NewSlider(0, math.Max(1, src.Duration))
+	slider.Step = 0.5
+	updateProgress := func(val float64) {
+		updatingProgress = true
+		currentTime.SetText(formatClock(val))
+		slider.SetValue(val)
+		updatingProgress = false
+	}
+	if state.playSess != nil {
+		state.playSess.prog = updateProgress
+	}
+	if state.playSess == nil {
+		state.playSess = newPlaySession(src.Path, src.Width, src.Height, src.FrameRate, int(targetWidth-28), int(targetHeight-40), updateProgress, img)
+	}
 
 	var controls fyne.CanvasObject
 	if usePlayer {
-		var updatingVolume bool
-		var slider *widget.Slider
 		var volIcon *widget.Button
-
+		var updatingVolume bool
+		seek := func(val float64) {
+			if state.playSess != nil {
+				state.playSess.Seek(val)
+			}
+		}
+		slider.OnChanged = func(val float64) {
+			if updatingProgress {
+				return
+			}
+			updateProgress(val)
+			seek(val)
+		}
 		updateVolIcon := func() {
 			if volIcon == nil {
 				return
@@ -892,19 +926,8 @@ func buildVideoPane(state *appState, min fyne.Size, src *videoSource, onCover fu
 				volIcon.SetText("🔊")
 			}
 		}
-
-		slider = widget.NewSlider(0, math.Max(1, src.Duration))
-		slider.Step = 0.5
-		slider.OnChanged = func(val float64) {
-			currentTime.SetText(formatClock(val))
-			if state.player != nil && state.playerReady {
-				if err := state.player.Seek(val); err != nil {
-					debugLog(logCatFFMPEG, "player seek failed: %v", err)
-				}
-			}
-		}
 		volIcon = makeIconButton("🔊", "Mute/Unmute", func() {
-			if state.player == nil {
+			if state.playSess == nil {
 				return
 			}
 			if state.playerMuted {
@@ -914,18 +937,16 @@ func buildVideoPane(state *appState, min fyne.Size, src *videoSource, onCover fu
 				}
 				state.playerVolume = target
 				state.playerMuted = false
-				updatingVolume = true
+				if state.playSess != nil {
-				slider.SetValue(target)
+					state.playSess.SetVolume(target)
-				updatingVolume = false
+				}
-				_ = state.player.SetVolume(target)
 			} else {
 				state.lastVolume = state.playerVolume
 				state.playerVolume = 0
 				state.playerMuted = true
-				updatingVolume = true
+				if state.playSess != nil {
-				slider.SetValue(0)
+					state.playSess.SetVolume(0)
-				updatingVolume = false
+				}
-				_ = state.player.SetVolume(0)
 			}
 			updateVolIcon()
 		})
@@ -943,39 +964,28 @@ func buildVideoPane(state *appState, min fyne.Size, src *videoSource, onCover fu
 			} else {
 				state.playerMuted = true
 			}
-			if state.player != nil && state.playerReady {
+			if state.playSess != nil {
-				if err := state.player.SetVolume(val); err != nil {
+				state.playSess.SetVolume(val)
-					debugLog(logCatFFMPEG, "player volume failed: %v", err)
-				}
 			}
 			updateVolIcon()
 		}
 		updateVolIcon()
 		volSlider.Refresh()
 		playBtn := makeIconButton("▶/⏸", "Play/Pause", func() {
-			if state.player == nil {
+			if state.playSess == nil {
-				return
+				state.playSess = newPlaySession(src.Path, src.Width, src.Height, src.FrameRate, int(targetWidth-28), int(targetHeight-40), updateProgress, img)
+				state.playSess.SetVolume(state.playerVolume)
 			}
 			if state.playerPaused {
-				if err := state.player.Play(); err != nil {
+				state.playSess.Play()
-					debugLog(logCatFFMPEG, "player play failed: %v", err)
-					return
-				}
 				state.playerPaused = false
 			} else {
-				if err := state.player.Pause(); err != nil {
+				state.playSess.Pause()
-					debugLog(logCatFFMPEG, "player pause failed: %v", err)
-					return
-				}
 				state.playerPaused = true
 			}
 		})
 		fullBtn := makeIconButton("⛶", "Toggle fullscreen", func() {
-			if state.player != nil {
+			// Placeholder: embed fullscreen toggle into playback surface later.
-				if err := state.player.FullScreen(); err != nil {
-					debugLog(logCatFFMPEG, "player fullscreen failed: %v", err)
-				}
-			}
 		})
 		volBox := container.NewHBox(volIcon, container.NewMax(volSlider))
 		progress := container.NewBorder(nil, nil, currentTime, totalTime, container.NewMax(slider))
@@ -1049,6 +1059,260 @@ func moduleColor(id string) color.Color {
 	return queueColor
 }
 
+type playSession struct {
+	path      string
+	fps       float64
+	width     int
+	height    int
+	targetW   int
+	targetH   int
+	volume    float64
+	muted     bool
+	paused    bool
+	current   float64
+	stop      chan struct{}
+	done      chan struct{}
+	prog      func(float64)
+	img       *canvas.Image
+	mu        sync.Mutex
+	videoCmd  *exec.Cmd
+	audioCmd  *exec.Cmd
+	audioCtx  *oto.Context
+	audioPlay io.Closer
+}
+
+func newPlaySession(path string, w, h int, fps float64, targetW, targetH int, prog func(float64), img *canvas.Image) *playSession {
+	if fps <= 0 {
+		fps = 24
+	}
+	if targetW <= 0 {
+		targetW = 640
+	}
+	if targetH <= 0 {
+		targetH = int(float64(targetW) * (float64(h) / float64(maxInt(w, 1))))
+	}
+	return &playSession{
+		path:    path,
+		fps:     fps,
+		width:   w,
+		height:  h,
+		targetW: targetW,
+		targetH: targetH,
+		volume:  100,
+		stop:    make(chan struct{}),
+		done:    make(chan struct{}),
+		prog:    prog,
+		img:     img,
+	}
+}
+
+func (p *playSession) Play() {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if p.videoCmd == nil && p.audioCmd == nil {
+		p.startLocked(p.current)
+		return
+	}
+	p.paused = false
+}
+
+func (p *playSession) Pause() {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.paused = true
+}
+
+func (p *playSession) Seek(offset float64) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.current = offset
+	p.stopLocked()
+	p.startLocked(offset)
+}
+
+func (p *playSession) SetVolume(v float64) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if v < 0 {
+		v = 0
+	}
+	if v > 100 {
+		v = 100
+	}
+	p.volume = v
+	if v > 0 {
+		p.muted = false
+	} else {
+		p.muted = true
+	}
+}
+
+func (p *playSession) Stop() {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.stopLocked()
+}
+
+func (p *playSession) stopLocked() {
+	select {
+	case <-p.stop:
+	default:
+		close(p.stop)
+	}
+	if p.videoCmd != nil && p.videoCmd.Process != nil {
+		_ = p.videoCmd.Process.Kill()
+	}
+	if p.audioCmd != nil && p.audioCmd.Process != nil {
+		_ = p.audioCmd.Process.Kill()
+	}
+	if p.audioPlay != nil {
+		p.audioPlay.Close()
+	}
+	if p.audioCtx != nil {
+		p.audioCtx.Close()
+	}
+	p.videoCmd = nil
+	p.audioCmd = nil
+	p.audioPlay = nil
+	p.audioCtx = nil
+	p.stop = make(chan struct{})
+	p.done = make(chan struct{})
+}
+
+func (p *playSession) startLocked(offset float64) {
+	p.paused = false
+	p.current = offset
+	p.runVideo(offset)
+	p.runAudio(offset)
+}
+
+func (p *playSession) runVideo(offset float64) {
+	cmd := exec.Command("ffmpeg",
+		"-hide_banner", "-loglevel", "error",
+		"-ss", fmt.Sprintf("%.3f", offset),
+		"-i", p.path,
+		"-vf", fmt.Sprintf("scale=%d:%d", p.targetW, p.targetH),
+		"-f", "rawvideo",
+		"-pix_fmt", "rgb24",
+		"-r", fmt.Sprintf("%.3f", p.fps),
+		"-",
+	)
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return
+	}
+	if err := cmd.Start(); err != nil {
+		return
+	}
+	p.videoCmd = cmd
+	frameSize := p.targetW * p.targetH * 3
+	buf := make([]byte, frameSize)
+	go func() {
+		defer cmd.Process.Kill()
+		for {
+			select {
+			case <-p.stop:
+				return
+			default:
+			}
+			if p.paused {
+				time.Sleep(30 * time.Millisecond)
+				continue
+			}
+			_, err := io.ReadFull(stdout, buf)
+			if err != nil {
+				return
+			}
+			frame := image.NewNRGBA(image.Rect(0, 0, p.targetW, p.targetH))
+			copy(frame.Pix, buf)
+			fyne.CurrentApp().Driver().DoFromGoroutine(func() {
+				if p.img != nil {
+					p.img.Image = frame
+					p.img.Refresh()
+				}
+			}, false)
+			p.current += 1.0 / p.fps
+			if p.prog != nil {
+				p.prog(p.current)
+			}
+		}
+	}()
+}
+
+func (p *playSession) runAudio(offset float64) {
+	const sampleRate = 48000
+	const channels = 2
+	const bytesPerSample = 2
+	cmd := exec.Command("ffmpeg",
+		"-hide_banner", "-loglevel", "error",
+		"-ss", fmt.Sprintf("%.3f", offset),
+		"-i", p.path,
+		"-vn",
+		"-ac", fmt.Sprintf("%d", channels),
+		"-ar", fmt.Sprintf("%d", sampleRate),
+		"-f", "s16le",
+		"-",
+	)
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return
+	}
+	if err := cmd.Start(); err != nil {
+		return
+	}
+	p.audioCmd = cmd
+	ctx, err := oto.NewContext(sampleRate, channels, bytesPerSample, 2048)
+	if err != nil {
+		return
+	}
+	player := ctx.NewPlayer()
+	p.audioCtx = ctx
+	p.audioPlay = player
+	go func() {
+		defer cmd.Process.Kill()
+		defer player.Close()
+		defer ctx.Close()
+		chunk := make([]byte, 4096)
+		for {
+			select {
+			case <-p.stop:
+				return
+			default:
+			}
+			if p.paused {
+				time.Sleep(30 * time.Millisecond)
+				continue
+			}
+			n, err := stdout.Read(chunk)
+			if n > 0 {
+				gain := p.volume / 100.0
+				if p.muted || gain <= 0 {
+					for i := 0; i < n; i++ {
+						chunk[i] = 0
+					}
+				} else if gain < 0.999 || gain > 1.001 {
+					for i := 0; i+1 < n; i += 2 {
+						sample := int16(chunk[i]) | int16(chunk[i+1])<<8
+						amp := int(float64(sample) * gain)
+						if amp > math.MaxInt16 {
+							amp = math.MaxInt16
+						}
+						if amp < math.MinInt16 {
+							amp = math.MinInt16
+						}
+						chunk[i] = byte(amp)
+						chunk[i+1] = byte(amp >> 8)
+					}
+				}
+				player.Write(chunk[:n])
+			}
+			if err != nil {
+				return
+			}
+		}
+	}()
+}
+
 type previewAnimator struct {
 	frames  []string
 	img     *canvas.Image
@@ -1184,6 +1448,10 @@ func (s *appState) handleDrop(items []fyne.URI) {
 
 func (s *appState) loadVideo(path string) {
 	win := s.window
+	if s.playSess != nil {
+		s.playSess.Stop()
+		s.playSess = nil
+	}
 	src, err := probeVideo(path)
 	if err != nil {
 		debugLog(logCatFFMPEG, "ffprobe failed for %s: %v", path, err)
@@ -1515,6 +1783,13 @@ func channelLabel(ch int) string {
 	}
 }
 
+func maxInt(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
 func makeIconButton(symbol, tooltip string, tapped func()) *widget.Button {
 	btn := widget.NewButton(symbol, tapped)
 	btn.Importance = widget.LowImportance