CLI: Add "photoprism dl --format-sort" flag and dl-method env variable

Signed-off-by: Michael Mayer <michael@photoprism.app>

internal/commands/download.go

@@ -71,6 +71,11 @@ var DownloadCommand = &cli.Command{
 			Value:   "auto",
 			Usage:   "remux `POLICY` for videos when using --dl-method file: auto (skip if MP4), always, or skip",
 		},
+		&cli.StringFlag{
+			Name:    "format-sort",
+			Aliases: []string{"s"},
+			Usage:   "custom FORMAT sort expression passed to yt-dlp",
+		},
 	},
 	Action: downloadAction,
 }
@@ -145,12 +150,18 @@ func downloadAction(ctx *cli.Context) error {
 	cookies := strings.TrimSpace(ctx.String("cookies"))
 	// cookiesFromBrowser := strings.TrimSpace(ctx.String("cookies-from-browser"))
 	addHeaders := ctx.StringSlice("add-header")
-	method := strings.ToLower(strings.TrimSpace(ctx.String("dl-method")))
-	if method == "" {
-		method = "pipe"
+	flagMethod := ""
+	if ctx.IsSet("dl-method") {
+		flagMethod = ctx.String("dl-method")
 	}
-	if method != "pipe" && method != "file" {
-		return fmt.Errorf("invalid --dl-method: %s (expected 'pipe' or 'file')", method)
+	method, _, err := resolveDownloadMethod(flagMethod)
+	if err != nil {
+		return err
+	}
+	formatSort := strings.TrimSpace(ctx.String("format-sort"))
+	sortingFormat := formatSort
+	if sortingFormat == "" && method == "pipe" {
+		sortingFormat = pipeSortingFormat
 	}
 	fileRemux := strings.ToLower(strings.TrimSpace(ctx.String("file-remux")))
 	if fileRemux == "" {
@@ -201,7 +212,7 @@ func downloadAction(ctx *cli.Context) error {
 			opt := dl.Options{
 				MergeOutputFormat: fs.VideoMp4.String(),
 				RemuxVideo:        fs.VideoMp4.String(),
-				SortingFormat:     "lang,quality,res,fps,codec:avc:m4a,channels,size,br,asr,proto,ext,hasaud,source,id",
+				SortingFormat:     sortingFormat,
 				Cookies:           cookies,
 				AddHeaders:        addHeaders,
 			}
@@ -209,6 +220,9 @@ func downloadAction(ctx *cli.Context) error {
 			result, err := dl.NewMetadata(context.Background(), u.String(), opt)
 			if err != nil {
 				log.Errorf("metadata failed: %v", err)
+				if hint, ok := missingFormatsHint(err); ok {
+					log.Info(hint)
+				}
 				failures++
 				continue
 			}

internal/commands/download_e2e_test.go

@@ -40,7 +40,9 @@ func createFakeYtDlp(t *testing.T) string {
 	if runtime.GOOS == "windows" {
 		// Not needed in CI/dev container. Keep simple stub.
 		content := "@echo off\r\n" +
+			"if not \"%YTDLP_ARGS_LOG%\"==\"\" echo %* >> %YTDLP_ARGS_LOG%\r\n" +
 			"for %%A in (%*) do (\r\n" +
+			"  if \"%%~A\"==\"--version\" ( echo 2025.09.23 & goto :eof )\r\n" +
 			"  if \"%%~A\"==\"--dump-single-json\" ( echo {\"id\":\"abc\",\"title\":\"Test\",\"url\":\"http://example.com\",\"_type\":\"video\"} & goto :eof )\r\n" +
 			")\r\n"
 		if err := os.WriteFile(path, []byte(content), 0o755); err != nil {
@@ -51,6 +53,9 @@ func createFakeYtDlp(t *testing.T) string {
 	var b strings.Builder
 	b.WriteString("#!/usr/bin/env bash\n")
 	b.WriteString("set -euo pipefail\n")
+	b.WriteString("ARGS_LOG=\"${YTDLP_ARGS_LOG:-}\"\n")
+	b.WriteString("if [[ -n \"$ARGS_LOG\" ]]; then echo \"$*\" >> \"$ARGS_LOG\"; fi\n")
+	b.WriteString("for a in \"$@\"; do if [[ \"$a\" == \"--version\" ]]; then echo '2025.09.23'; exit 0; fi; done\n")
 	b.WriteString("OUT_TPL=\"\"\n")
 	b.WriteString("i=0; while [[ $i -lt $# ]]; do i=$((i+1)); arg=\"${!i}\"; if [[ \"$arg\" == \"--dump-single-json\" ]]; then echo '{\"id\":\"abc\",\"title\":\"Test\",\"url\":\"http://example.com\",\"_type\":\"video\"}'; exit 0; fi; if [[ \"$arg\" == \"--output\" ]]; then i=$((i+1)); OUT_TPL=\"${!i}\"; fi; done\n")
 	b.WriteString("if [[ $* == *'--print '* ]]; then OUT=\"$OUT_TPL\"; OUT=${OUT//%(id)s/abc}; OUT=${OUT//%(ext)s/mp4}; mkdir -p \"$(dirname \"$OUT\")\"; CONTENT=\"${YTDLP_DUMMY_CONTENT:-dummy}\"; echo \"$CONTENT\" > \"$OUT\"; echo \"$OUT\"; exit 0; fi\n")
@@ -65,6 +70,7 @@ func TestDownloadImpl_FileMethod_AutoSkipsRemux(t *testing.T) {
 	t.Setenv("YTDLP_FORCE_SHELL", "1")
 	// Prefer using in-process fake to avoid exec restrictions.
 	t.Setenv("YTDLP_FAKE", "1")
+	dl.ResetVersionWarningForTest()
 	fake := createFakeYtDlp(t)
 	orig := dl.YtDlpBin
 	defer func() { dl.YtDlpBin = orig }()
@@ -110,6 +116,7 @@ func TestDownloadImpl_FileMethod_Skip_NoRemux(t *testing.T) {
 	t.Setenv("YTDLP_FORCE_SHELL", "1")
 	// Prefer using in-process fake to avoid exec restrictions.
 	t.Setenv("YTDLP_FAKE", "1")
+	dl.ResetVersionWarningForTest()
 	fake := createFakeYtDlp(t)
 	orig := dl.YtDlpBin
 	defer func() { dl.YtDlpBin = orig }()
@@ -182,6 +189,7 @@ func TestDownloadImpl_FileMethod_Always_RemuxFails(t *testing.T) {
 	t.Setenv("YTDLP_FORCE_SHELL", "1")
 	// Prefer using in-process fake to avoid exec restrictions.
 	t.Setenv("YTDLP_FAKE", "1")
+	dl.ResetVersionWarningForTest()
 	fake := createFakeYtDlp(t)
 	orig := dl.YtDlpBin
 	defer func() { dl.YtDlpBin = orig }()

internal/commands/download_format_test.go

@@ -0,0 +1,171 @@
+package commands
+
+import (
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/photoprism/photoprism/internal/photoprism/dl"
+	"github.com/photoprism/photoprism/internal/photoprism/get"
+)
+
+func createArgsLoggingYtDlp(t *testing.T) string {
+	t.Helper()
+	dir := t.TempDir()
+	path := filepath.Join(dir, "yt-dlp")
+
+	if runtime.GOOS == "windows" {
+		var b strings.Builder
+		b.WriteString("@echo off\r\n")
+		b.WriteString("if not \"%YTDLP_ARGS_LOG%\"==\"\" echo %* >> %YTDLP_ARGS_LOG%\r\n")
+		b.WriteString("for %%A in (%*) do (\r\n")
+		b.WriteString("  if \"%%~A\"==\"--version\" ( echo 2025.09.23 & goto :eof )\r\n")
+		b.WriteString("  if \"%%~A\"==\"--dump-single-json\" ( echo {\"id\":\"abc\",\"title\":\"Test\",\"url\":\"http://example.com\",\"_type\":\"video\"} & goto :eof )\r\n")
+		b.WriteString(")\r\n")
+		if err := os.WriteFile(path, []byte(b.String()), 0o755); err != nil {
+			t.Fatalf("failed to write fake yt-dlp: %v", err)
+		}
+		return path
+	}
+
+	var b strings.Builder
+	b.WriteString("#!/usr/bin/env bash\n")
+	b.WriteString("set -euo pipefail\n")
+	b.WriteString("ARGS_LOG=\"${YTDLP_ARGS_LOG:-}\"\n")
+	b.WriteString("if [[ -n \"$ARGS_LOG\" ]]; then echo \"$*\" >> \"$ARGS_LOG\"; fi\n")
+	b.WriteString("for a in \"$@\"; do if [[ \"$a\" == \"--version\" ]]; then echo '2025.09.23'; exit 0; fi; done\n")
+	b.WriteString("OUT_TPL=\"\"\n")
+	b.WriteString("i=0; while [[ $i -lt $# ]]; do i=$((i+1)); arg=\"${!i}\"; if [[ \"$arg\" == \"--output\" ]]; then i=$((i+1)); OUT_TPL=\"${!i}\"; fi; done\n")
+	b.WriteString("for a in \"$@\"; do if [[ \"$a\" == \"--dump-single-json\" ]]; then echo '{\"id\":\"abc\",\"title\":\"Test\",\"url\":\"http://example.com\",\"_type\":\"video\"}'; exit 0; fi; done\n")
+	b.WriteString("for a in \"$@\"; do if [[ \"$a\" == \"--print\" ]]; then OUT=\"$OUT_TPL\"; OUT=${OUT//%(id)s/abc}; OUT=${OUT//%(ext)s/mp4}; mkdir -p \"$(dirname \"$OUT\")\"; CONTENT=\"${YTDLP_DUMMY_CONTENT:-dummy}\"; printf \"%s\" \"$CONTENT\" > \"$OUT\"; echo \"$OUT\"; exit 0; fi; done\n")
+	b.WriteString("echo '[download]' 1>&2\n")
+	b.WriteString("echo 'DATA'\n")
+
+	if err := os.WriteFile(path, []byte(b.String()), 0o755); err != nil {
+		t.Fatalf("failed to write fake yt-dlp: %v", err)
+	}
+	return path
+}
+
+func TestRunDownload_FileMethod_OmitsFormatSort(t *testing.T) {
+	t.Setenv("YTDLP_FORCE_SHELL", "1")
+	argsLog := filepath.Join(t.TempDir(), "args.log")
+	t.Setenv("YTDLP_ARGS_LOG", argsLog)
+	outDir := t.TempDir()
+	outFile := filepath.Join(outDir, "ppdl_test.mp4")
+	t.Setenv("YTDLP_OUTPUT_FILE", outFile)
+	t.Setenv("YTDLP_DUMMY_CONTENT", "quality-test")
+	dl.ResetVersionWarningForTest()
+
+	fake := createArgsLoggingYtDlp(t)
+	origBin := dl.YtDlpBin
+	dl.YtDlpBin = fake
+	defer func() { dl.YtDlpBin = origBin }()
+
+	conf := get.Config()
+	if conf == nil {
+		t.Fatalf("missing test config")
+	}
+	conf.RegisterDb()
+
+	// Avoid background ffmpeg work that could interfere with the test environment.
+	opt := conf.Options()
+	origFFmpeg := opt.FFmpegBin
+	opt.FFmpegBin = "/bin/false"
+	settings := conf.Settings()
+	origConvert := settings.Index.Convert
+	settings.Index.Convert = false
+
+	dest := "dl-quality"
+	if err := runDownload(conf, DownloadOpts{
+		Dest:      dest,
+		Method:    "file",
+		FileRemux: "skip",
+	}, []string{"https://example.com/video"}); err != nil {
+		t.Fatalf("runDownload failed: %v", err)
+	}
+
+	// Ensure Originals cleanup so subsequent tests stay isolated.
+	t.Cleanup(func() {
+		_ = os.RemoveAll(filepath.Join(conf.OriginalsPath(), dest))
+		settings.Index.Convert = origConvert
+		opt.FFmpegBin = origFFmpeg
+	})
+
+	// Give the logging script a moment to flush in slower environments.
+	time.Sleep(20 * time.Millisecond)
+
+	data, err := os.ReadFile(argsLog)
+	if err != nil {
+		t.Fatalf("reading args log failed: %v", err)
+	}
+	content := string(data)
+	if !strings.Contains(content, "--print") {
+		t.Fatalf("expected file download invocation to be logged, got: %q", content)
+	}
+	if strings.Contains(content, "--format-sort") {
+		t.Fatalf("file method should not pass --format-sort; args: %q", content)
+	}
+}
+
+func TestRunDownload_FileMethod_WithFormatSort(t *testing.T) {
+	t.Setenv("YTDLP_FORCE_SHELL", "1")
+	argsLog := filepath.Join(t.TempDir(), "args.log")
+	t.Setenv("YTDLP_ARGS_LOG", argsLog)
+	outDir := t.TempDir()
+	outFile := filepath.Join(outDir, "ppdl_fmt.mp4")
+	t.Setenv("YTDLP_OUTPUT_FILE", outFile)
+	t.Setenv("YTDLP_DUMMY_CONTENT", "quality-test-override")
+	dl.ResetVersionWarningForTest()
+
+	fake := createArgsLoggingYtDlp(t)
+	origBin := dl.YtDlpBin
+	dl.YtDlpBin = fake
+	defer func() { dl.YtDlpBin = origBin }()
+
+	conf := get.Config()
+	if conf == nil {
+		t.Fatalf("missing test config")
+	}
+	conf.RegisterDb()
+
+	opt := conf.Options()
+	origFFmpeg := opt.FFmpegBin
+	opt.FFmpegBin = "/bin/false"
+	settings := conf.Settings()
+	origConvert := settings.Index.Convert
+	settings.Index.Convert = false
+
+	dest := "dl-format-sort"
+	if err := runDownload(conf, DownloadOpts{
+		Dest:       dest,
+		Method:     "file",
+		FileRemux:  "skip",
+		FormatSort: "res,fps,size",
+	}, []string{"https://example.com/video"}); err != nil {
+		t.Fatalf("runDownload failed with custom format-sort: %v", err)
+	}
+
+	t.Cleanup(func() {
+		_ = os.RemoveAll(filepath.Join(conf.OriginalsPath(), dest))
+		settings.Index.Convert = origConvert
+		opt.FFmpegBin = origFFmpeg
+	})
+
+	time.Sleep(20 * time.Millisecond)
+
+	data, err := os.ReadFile(argsLog)
+	if err != nil {
+		t.Fatalf("reading args log failed: %v", err)
+	}
+	content := string(data)
+	if !strings.Contains(content, "--format-sort") {
+		t.Fatalf("expected --format-sort to be passed; args: %q", content)
+	}
+	if !strings.Contains(content, "res,fps,size") {
+		t.Fatalf("expected custom format-sort expression to be present; args: %q", content)
+	}
+}

internal/commands/download_help_test.go

@@ -10,10 +10,11 @@ func TestDownloadCommand_HelpFlagsAndArgs(t *testing.T) {
 	}
 	// Verify new flags are present by name
 	want := map[string]bool{
-		"cookies":    false,
-		"add-header": false,
-		"dl-method":  false,
-		"file-remux": false,
+		"cookies":     false,
+		"add-header":  false,
+		"dl-method":   false,
+		"file-remux":  false,
+		"format-sort": false,
 	}
 	for _, f := range DownloadCommand.Flags {
 		name := f.Names()[0]

internal/commands/download_impl.go

@@ -22,6 +22,8 @@ import (
 	"github.com/photoprism/photoprism/pkg/service/http/scheme"
 )
 
+const pipeSortingFormat = "lang,quality,res,fps,codec:avc:m4a,channels,size,br,asr,proto,ext,hasaud,source,id"
+
 // DownloadOpts contains the command options used by runDownload.
 type DownloadOpts struct {
 	Dest               string
@@ -30,6 +32,7 @@ type DownloadOpts struct {
 	AddHeaders         []string
 	Method             string // pipe|file
 	FileRemux          string // always|auto|skip
+	FormatSort         string
 }
 
 // runDownload executes the download/import flow for the given inputs and options.
@@ -46,6 +49,10 @@ func runDownload(conf *config.Config, opts DownloadOpts, inputURLs []string) err
 		return fmt.Errorf("no download URLs provided")
 	}
 
+	if msg, ok := dl.VersionWarning(); ok {
+		log.Info(msg)
+	}
+
 	// Resolve destination folder
 	destFolder := opts.Dest
 	if destFolder == "" {
@@ -62,12 +69,14 @@ func runDownload(conf *config.Config, opts DownloadOpts, inputURLs []string) err
 	defer os.RemoveAll(downloadPath)
 
 	// Normalize method/remux policy
-	method := strings.ToLower(strings.TrimSpace(opts.Method))
-	if method == "" {
-		method = "pipe"
+	method, _, err := resolveDownloadMethod(opts.Method)
+	if err != nil {
+		return err
 	}
-	if method != "pipe" && method != "file" {
-		return fmt.Errorf("invalid method: %s", method)
+
+	sortingFormat := strings.TrimSpace(opts.FormatSort)
+	if sortingFormat == "" && method == "pipe" {
+		sortingFormat = pipeSortingFormat
 	}
 	fileRemux := strings.ToLower(strings.TrimSpace(opts.FileRemux))
 	if fileRemux == "" {
@@ -118,7 +127,7 @@ func runDownload(conf *config.Config, opts DownloadOpts, inputURLs []string) err
 			opt := dl.Options{
 				MergeOutputFormat:  fs.VideoMp4.String(),
 				RemuxVideo:         fs.VideoMp4.String(),
-				SortingFormat:      "lang,quality,res,fps,codec:avc:m4a,channels,size,br,asr,proto,ext,hasaud,source,id",
+				SortingFormat:      sortingFormat,
 				Cookies:            opts.Cookies,
 				CookiesFromBrowser: opts.CookiesFromBrowser,
 				AddHeaders:         opts.AddHeaders,
@@ -126,6 +135,9 @@ func runDownload(conf *config.Config, opts DownloadOpts, inputURLs []string) err
 			result, err := dl.NewMetadata(context.Background(), u.String(), opt)
 			if err != nil {
 				log.Errorf("metadata failed: %v", err)
+				if hint, ok := missingFormatsHint(err); ok {
+					log.Info(hint)
+				}
 				failures++
 				continue
 			}
@@ -225,3 +237,16 @@ func runDownload(conf *config.Config, opts DownloadOpts, inputURLs []string) err
 	log.Infof("completed in %s", elapsed)
 	return nil
 }
+
+func missingFormatsHint(err error) (string, bool) {
+	if err == nil {
+		return "", false
+	}
+
+	lower := strings.ToLower(err.Error())
+	if strings.Contains(lower, "requested format is not available") {
+		return "yt-dlp did not receive playable formats. Try downloading via yt-dlp --list-formats, or pass authenticated cookies with --cookies <file> so YouTube exposes video/audio streams.", true
+	}
+
+	return "", false
+}

internal/commands/download_impl_test.go

@@ -0,0 +1,56 @@
+package commands
+
+import (
+	"testing"
+
+	"github.com/photoprism/photoprism/internal/photoprism/dl"
+)
+
+func TestMissingFormatsHint(t *testing.T) {
+	hint, ok := missingFormatsHint(dl.YoutubedlError("Requested format is not available. Use --list-formats for a list of available formats"))
+	if !ok {
+		t.Fatalf("expected hint for missing formats error")
+	}
+	if hint == "" {
+		t.Fatalf("hint should not be empty")
+	}
+
+	if _, ok := missingFormatsHint(dl.YoutubedlError("some other error")); ok {
+		t.Fatalf("unexpected hint for unrelated error")
+	}
+}
+
+func TestResolveDownloadMethodEnv(t *testing.T) {
+	t.Setenv(downloadMethodEnv, "FILE")
+	method, fromEnv, err := resolveDownloadMethod("")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if method != "file" {
+		t.Fatalf("expected file, got %s", method)
+	}
+	if !fromEnv {
+		t.Fatalf("expected value to originate from env")
+	}
+}
+
+func TestResolveDownloadMethodInvalidEnv(t *testing.T) {
+	t.Setenv(downloadMethodEnv, "weird")
+	if _, _, err := resolveDownloadMethod(""); err == nil {
+		t.Fatalf("expected error for invalid env method")
+	}
+}
+
+func TestResolveDownloadMethodFlagTakesPriority(t *testing.T) {
+	t.Setenv(downloadMethodEnv, "file")
+	method, fromEnv, err := resolveDownloadMethod("pipe")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if method != "pipe" {
+		t.Fatalf("expected pipe, got %s", method)
+	}
+	if fromEnv {
+		t.Fatalf("did not expect env to be used when flag provided")
+	}
+}

internal/commands/download_method.go

@@ -0,0 +1,41 @@
+package commands
+
+import (
+	"fmt"
+	"os"
+	"strings"
+)
+
+const downloadMethodEnv = "PHOTOPRISM_DL_METHOD"
+
+// resolveDownloadMethod normalizes the download method by honoring the explicit flag
+// value first, then the environment variable PHOTOPRISM_DL_METHOD, and finally
+// defaulting to "pipe". It returns the resolved method, a boolean indicating whether
+// the value originated from the environment, or an error when the input is invalid.
+func resolveDownloadMethod(flagValue string) (string, bool, error) {
+	trimmed := strings.TrimSpace(flagValue)
+	method := strings.ToLower(trimmed)
+	fromEnv := false
+
+	if method == "" {
+		envValue := strings.TrimSpace(os.Getenv(downloadMethodEnv))
+		if envValue != "" {
+			method = strings.ToLower(envValue)
+			trimmed = envValue
+			fromEnv = true
+		}
+	}
+
+	if method == "" {
+		return "pipe", false, nil
+	}
+
+	if method != "pipe" && method != "file" {
+		if fromEnv {
+			return "", true, fmt.Errorf("invalid %s value: %s (expected 'pipe' or 'file')", downloadMethodEnv, trimmed)
+		}
+		return "", false, fmt.Errorf("invalid download method: %s (expected 'pipe' or 'file')", trimmed)
+	}
+
+	return method, fromEnv, nil
+}

internal/photoprism/dl/README.md

@@ -45,3 +45,5 @@ It currently supports two invocation methods:
 
 - Prefer the file method for sources with separate audio/video streams; the pipe method cannot always merge in that case.
 - When the CLI’s `--file-remux=auto` is used, the final ffmpeg remux is skipped for MP4 outputs that already include metadata.
+- Keep `yt-dlp` updated. Releases older than `2025.09.23` are known to miss YouTube video formats (SABR gating); the CLI now logs a warning when it detects an outdated build.
+- Users who favor one approach can set `PHOTOPRISM_DL_METHOD=file` (or `pipe`) in the environment to change the default without touching CLI flags.

internal/photoprism/dl/version.go

@@ -1,19 +1,91 @@
 package dl
 
 import (
-	"context"
+	"bytes"
+	"os"
 	"os/exec"
 	"strings"
+	"sync"
+	"time"
 )
 
-// Version of youtube-dl.
-// Might be a good idea to call at start to assert that youtube-dl can be found.
-func Version(ctx context.Context) (string, error) {
-	cmd := exec.CommandContext(ctx, FindYtDlpBin(), "--version")
-	versionBytes, cmdErr := cmd.Output()
-	if cmdErr != nil {
-		return "", cmdErr
+const minYtDlpVersion = "2025.09.23"
+
+var (
+	versionOnce    sync.Once
+	versionWarning string
+)
+
+// VersionWarning returns a warning message when the detected yt-dlp version is older
+// than the minimum recommended release. The check runs at most once per process.
+func VersionWarning() (string, bool) {
+	versionOnce.Do(func() {
+		if os.Getenv("YTDLP_FAKE") == "1" {
+			return
+		}
+
+		bin := FindYtDlpBin()
+		if bin == "" {
+			return
+		}
+
+		cmd := exec.Command(bin, "--version")
+		cmd.Env = os.Environ()
+		var out bytes.Buffer
+		cmd.Stdout = &out
+		cmd.Stderr = &out
+
+		if err := cmd.Run(); err != nil {
+			return
+		}
+
+		first := strings.Fields(out.String())
+		if len(first) == 0 {
+			return
+		}
+
+		ver := first[0]
+		if olderThan(ver, minYtDlpVersion) {
+			versionWarning = "Detected yt-dlp " + ver + ". Please update to " + minYtDlpVersion + " or newer so YouTube videos expose playable formats."
+		}
+	})
+
+	if versionWarning == "" {
+		return "", false
+	}
+	return versionWarning, true
+}
+
+func olderThan(current, minimum string) bool {
+	if current == "" {
+		return false
 	}
 
-	return strings.TrimSpace(string(versionBytes)), nil
+	c := truncateVersion(current)
+	m := truncateVersion(minimum)
+
+	if len(c) != len("2006.01.02") || len(m) != len("2006.01.02") {
+		return false
+	}
+
+	ct, err1 := time.Parse("2006.01.02", c)
+	mt, err2 := time.Parse("2006.01.02", m)
+	if err1 != nil || err2 != nil {
+		// fall back to lexical comparison which works for yyyy.mm.dd
+		return c < m
+	}
+	return ct.Before(mt)
+}
+
+func truncateVersion(v string) string {
+	if len(v) >= len("2006.01.02") {
+		return v[:len("2006.01.02")]
+	}
+	return v
+}
+
+// ResetVersionWarningForTest resets the cached version warning; intended for tests only.
+func ResetVersionWarningForTest() {
+	versionOnce = sync.Once{}
+	versionWarning = ""
 }

internal/photoprism/dl/version_test.go

@@ -1,32 +1,66 @@
 package dl
 
 import (
-	"context"
-	"regexp"
+	"os"
+	"path/filepath"
+	"runtime"
 	"strings"
 	"testing"
 )
 
-func TestVersion(t *testing.T) {
-	t.Run("Success", func(t *testing.T) {
-		versionRe := regexp.MustCompile(`^\d{4}\.\d{2}.\d{2}.*$`)
-		version, versionErr := Version(context.Background())
+func TestVersionWarning_OldVersion(t *testing.T) {
+	ResetVersionWarningForTest()
 
-		if versionErr != nil {
-			t.Fatalf("err: %s", versionErr)
-		}
+	bin := writeVersionScript(t, "2025.09.05")
+	orig := YtDlpBin
+	YtDlpBin = bin
+	defer func() { YtDlpBin = orig }()
 
-		if !versionRe.MatchString(version) {
-			t.Errorf("version %q does not match %q", version, versionRe)
-		}
-	})
-	t.Run("InvalidBin", func(t *testing.T) {
-		defer func(orig string) { YtDlpBin = orig }(YtDlpBin)
-		YtDlpBin = "/non-existing"
+	os.Unsetenv("YTDLP_FAKE")
 
-		_, versionErr := Version(context.Background())
-		if versionErr == nil || !strings.Contains(versionErr.Error(), "no such file or directory") {
-			t.Fatalf("err should be nil 'no such file or directory': %v", versionErr)
-		}
-	})
+	msg, ok := VersionWarning()
+	if !ok {
+		t.Fatalf("expected warning for old version")
+	}
+	if !strings.Contains(msg, minYtDlpVersion) {
+		t.Fatalf("warning missing minimum version: %s", msg)
+	}
+}
+
+func TestVersionWarning_NewEnough(t *testing.T) {
+	ResetVersionWarningForTest()
+
+	bin := writeVersionScript(t, "2025.09.23")
+	orig := YtDlpBin
+	YtDlpBin = bin
+	defer func() { YtDlpBin = orig }()
+
+	os.Unsetenv("YTDLP_FAKE")
+
+	if _, ok := VersionWarning(); ok {
+		t.Fatalf("did not expect warning for up-to-date version")
+	}
+}
+
+func writeVersionScript(t *testing.T, version string) string {
+	t.Helper()
+	dir := t.TempDir()
+	path := filepath.Join(dir, "yt-dlp")
+
+	if runtime.GOOS == "windows" {
+		content := "@echo off\r\n" +
+			"echo " + version + "\r\n"
+		if err := os.WriteFile(path, []byte(content), 0o755); err != nil {
+			t.Fatalf("failed to write fake yt-dlp: %v", err)
+		}
+		return path
+	}
+
+	content := "#!/usr/bin/env bash\n" +
+		"set -euo pipefail\n" +
+		"echo '" + version + "'\n"
+	if err := os.WriteFile(path, []byte(content), 0o755); err != nil {
+		t.Fatalf("failed to write fake yt-dlp: %v", err)
+	}
+	return path
 }