feat(media): read Dahua DVR .dav recordings through FFmpeg

README.ar.md

@@ -58,7 +58,7 @@
       تظهر الصيغ حيث أنت، ولا يظهر منها إلا ما يناسب الملفات التي تسحبها.
     </td>
     <td width="33%" valign="top">
-      <b>266 صيغة دون برامج أخرى</b><br>
+      <b>267 صيغة دون برامج أخرى</b><br>
       الصور وPDF وWord وExcel وPowerPoint وHWP والكتب الإلكترونية والأرشيفات والخطوط وCAD والنماذج ثلاثية الأبعاد والبيانات الجغرافية، كلها تعمل دون Office أو Hancom Office أو LibreOffice.
     </td>
     <td width="33%" valign="top">

README.es.md

@@ -56,7 +56,7 @@
       Los formatos aparecen donde ya estás, y solo los que tienen sentido para los archivos que arrastras.
     </td>
     <td width="33%" valign="top">
-      <b>266 formatos, sin otros programas</b><br>
+      <b>267 formatos, sin otros programas</b><br>
       Imágenes, PDF, Word, Excel, PowerPoint, HWP, libros electrónicos, archivos comprimidos, tipografías, CAD, modelos 3D y datos geoespaciales funcionan sin Office, Hancom Office ni LibreOffice.
     </td>
     <td width="33%" valign="top">

README.fr.md

@@ -56,7 +56,7 @@
       Les formats apparaissent là où vous êtes déjà, et seulement ceux qui ont un sens pour les fichiers que vous faites glisser.
     </td>
     <td width="33%" valign="top">
-      <b>266 formats, sans autre logiciel</b><br>
+      <b>267 formats, sans autre logiciel</b><br>
       Images, PDF, Word, Excel, PowerPoint, HWP, livres numériques, archives, polices, CAO, modèles 3D et données géospatiales fonctionnent sans Office, Hancom Office ni LibreOffice.
     </td>
     <td width="33%" valign="top">

README.hi.md

@@ -56,7 +56,7 @@
       फ़ॉर्मैट वहीं दिखते हैं जहाँ आप पहले से हैं, और सिर्फ़ वही जो आपकी खींची जा रही फ़ाइलों के लिए सही हों।
     </td>
     <td width="33%" valign="top">
-      <b>266 फ़ॉर्मैट, कोई और सॉफ़्टवेयर नहीं</b><br>
+      <b>267 फ़ॉर्मैट, कोई और सॉफ़्टवेयर नहीं</b><br>
       इमेज, PDF, Word, Excel, PowerPoint, HWP, ई-बुक, आर्काइव, फ़ॉन्ट, CAD, 3D मॉडल और भू-स्थानिक डेटा Office, Hancom Office या LibreOffice के बिना काम करते हैं।
     </td>
     <td width="33%" valign="top">

README.ja.md

@@ -56,7 +56,7 @@
       いま作業している場所に、ドラッグ中のファイルに合う形式だけが表示されます。
     </td>
     <td width="33%" valign="top">
-      <b>266形式、ほかのソフトは不要</b><br>
+      <b>267形式、ほかのソフトは不要</b><br>
       画像、PDF、Word、Excel、PowerPoint、HWP、電子書籍、アーカイブ、フォント、CAD、3Dモデル、地理空間データを、Office、Hancom Office、LibreOfficeなしで変換できます。
     </td>
     <td width="33%" valign="top">

README.ko.md

@@ -57,7 +57,7 @@
       끌고 있는 파일에 맞는 형식만 지금 있는 자리에 나타나요.
     </td>
     <td width="33%" valign="top">
-      <b>266가지 형식, 다른 프로그램 없이</b><br>
+      <b>267가지 형식, 다른 프로그램 없이</b><br>
       이미지, PDF, 워드, 엑셀, 파워포인트, HWP, 전자책, 압축 파일, 글꼴, CAD, 3D 모델, 지리 정보 데이터를 오피스·한컴오피스·LibreOffice 없이 변환해요.
     </td>
     <td width="33%" valign="top">

README.md

@@ -56,7 +56,7 @@
       The formats appear where you already are, only the ones that make sense for the files you drag.
     </td>
     <td width="33%" valign="top">
-      <b>266 formats, no other software</b><br>
+      <b>267 formats, no other software</b><br>
       Images, PDF, Word, Excel, PowerPoint, HWP, e-books, archives, fonts, CAD, 3D models and geospatial data work without Office, Hancom Office or LibreOffice.
     </td>
     <td width="33%" valign="top">

README.pl.md

@@ -56,7 +56,7 @@
       Formaty pojawiają się tam, gdzie już jesteś, i tylko te, które pasują do przeciąganych plików.
     </td>
     <td width="33%" valign="top">
-      <b>266 formatów bez dodatkowych programów</b><br>
+      <b>267 formatów bez dodatkowych programów</b><br>
       Obrazy, PDF, Word, Excel, PowerPoint, HWP, e-booki, archiwa, czcionki, CAD, modele 3D i dane geoprzestrzenne działają bez pakietu Office, Hancom Office i LibreOffice.
     </td>
     <td width="33%" valign="top">

README.pt-BR.md

@@ -56,7 +56,7 @@
       Os formatos aparecem onde você já está, só os que fazem sentido para os arquivos que você arrasta.
     </td>
     <td width="33%" valign="top">
-      <b>266 formatos, sem outro programa</b><br>
+      <b>267 formatos, sem outro programa</b><br>
       Imagens, PDF, Word, Excel, PowerPoint, HWP, e-books, arquivos compactados, fontes, CAD, modelos 3D e dados geoespaciais funcionam sem Office, Hancom Office ou LibreOffice.
     </td>
     <td width="33%" valign="top">

README.pt-PT.md

@@ -56,7 +56,7 @@
       Os formatos aparecem onde estás, apenas os que fazem sentido para os ficheiros que arrastas.
     </td>
     <td width="33%" valign="top">
-      <b>266 formatos, sem outro software</b><br>
+      <b>267 formatos, sem outro software</b><br>
       Imagens, PDF, Word, Excel, PowerPoint, HWP, livros digitais, arquivos, tipos de letra, CAD, modelos 3D e dados geoespaciais funcionam sem Office, Hancom Office ou LibreOffice.
     </td>
     <td width="33%" valign="top">

README.ru.md

@@ -56,7 +56,7 @@
       Форматы появляются там, где вы уже работаете, и только те, что подходят перетаскиваемым файлам.
     </td>
     <td width="33%" valign="top">
-      <b>266 форматов без лишних программ</b><br>
+      <b>267 форматов без лишних программ</b><br>
       Изображения, PDF, Word, Excel, PowerPoint, HWP, электронные книги, архивы, шрифты, чертежи CAD, 3D-модели и геоданные работают без Office, Hancom Office и LibreOffice.
     </td>
     <td width="33%" valign="top">

README.th.md

@@ -56,7 +56,7 @@
       ฟอร์แมตที่เหมาะสมจะแสดงขึ้นตรงจุดที่คุณทำงานอยู่ โดยแสดงเฉพาะฟอร์แมตที่ใช้ได้กับไฟล์ที่คุณลากเท่านั้น
     </td>
     <td width="33%" valign="top">
-      <b>266 ฟอร์แมต โดยไม่ต้องลงโปรแกรมอื่นเพิ่ม</b><br>
+      <b>267 ฟอร์แมต โดยไม่ต้องลงโปรแกรมอื่นเพิ่ม</b><br>
       รูปภาพ, PDF, Word, Excel, PowerPoint, HWP, อีบุ๊ก, ไฟล์บีบอัด, ฟอนต์, CAD, โมเดล 3D และข้อมูลเชิงพื้นที่ ทำงานได้โดยไม่ต้องมี Microsoft Office, Hancom Office หรือ LibreOffice
     </td>
     <td width="33%" valign="top">

README.zh-CN.md

@@ -56,7 +56,7 @@
       只显示适合当前拖动文件的格式，就在你所在的位置。
     </td>
     <td width="33%" valign="top">
-      <b>266 种格式，无需其他软件</b><br>
+      <b>267 种格式，无需其他软件</b><br>
       图片、PDF、Word、Excel、PowerPoint、HWP、电子书、压缩包、字体、CAD、3D 模型和地理信息数据，无需 Office、韩文办公软件或 LibreOffice。
     </td>
     <td width="33%" valign="top">

README.zh-TW.md

@@ -56,7 +56,7 @@
       只顯示適合當前拖曳檔案的格式，就在你所在的位置。
     </td>
     <td width="33%" valign="top">
-      <b>266 種格式，無需其他軟體</b><br>
+      <b>267 種格式，無需其他軟體</b><br>
       圖片、PDF、Word、Excel、PowerPoint、HWP、電子書、壓縮檔、字型、CAD、3D 模型和地理資訊資料，無需 Office、韓文文書軟體或 LibreOffice。
     </td>
     <td width="33%" valign="top">

docs/ENGINES.md

@@ -1463,6 +1463,11 @@ A self-contained `.m4s` (read only, #354), a fragmented MP4 that starts with `ft
 and goes to every video and audio target. A DASH media segment, whose top-level boxes reach a `moof` before any
 `moov`, plays only with a separate init segment; Filee refuses it before FFmpeg runs, with its own message
 (`error.m4s_needs_init`), instead of FFmpeg's demuxer error.
+Dahua DVR / NVR recordings (`.dav`, read only, #594) are read by FFmpeg's `dhav` demuxer, which finds them by the
+`DHAV` chunks they are made of, and go to every video and audio target. Their H.264 / H.265 video is copied where
+the target and preset allow it (`CanCopyVideo`), like any other container's; G.711 sound is encoded for targets that
+can't hold it. The chunks carry the camera's wall-clock time, so FFmpeg reports the recording date as the start time;
+the output starts at zero.
 A Video CD's `MPEGAV/AVSEQ01.DAT` (MPEG-1 in a RIFF/CDXA wrapper) counts as MPEG: `.dat` is an extension of that
 format, and FFmpeg reads what the file holds, so a `.dat` with no video in it fails instead of making a file.
 

src/Filee.Core/Formats/FormatRegistry.cs

@@ -230,6 +230,9 @@ public static class FormatRegistry
         // Fragmented MP4 (#354): an .m4s with its own moov (ftyp + moov, then styp / sidx / moof / mdat) is read by FFmpeg;
         // a DASH media segment that needs a separate init segment is refused (DashSegment).
         new("m4s", "M4S", FormatCategory.Video, ["m4s"], Writable: false),
+        // Dahua and similar DVR / NVR recordings (#594): FFmpeg's dhav demuxer reads them (H.264 / H.265 video, often
+        // with G.711 or AAC sound).
+        new("dav", "DAV", FormatCategory.Video, ["dav"], Writable: false),
         // Raw H.265 / H.264 streams with no container, as security cameras and VMS software export them (issue #301).
         new("h265", "H.265", FormatCategory.Video, ["h265", "265", "hevc"], Writable: false),
         new("h264", "H.264", FormatCategory.Video, ["h264", "264"], Writable: false),

src/Filee.Core/Settings/AppSettings.cs

@@ -123,7 +123,7 @@ public static bool IsFlipKeyAllowed(string key, IEnumerable<TriggerGesture> gest
 public sealed class AppSettings
 {
     /// <summary>Current schema version. Increase when the format changes and add a migration.</summary>
-    public const int CurrentSchemaVersion = 49;
+    public const int CurrentSchemaVersion = 50;
 
     public int SchemaVersion { get; set; } = CurrentSchemaVersion;
 

src/Filee.Core/Settings/UserDataStore.cs

@@ -890,9 +890,12 @@ public static bool ApplyToLibrary(int from, List<Preset> presets, List<ToolbarPr
         if (from < 48)
             changed |= LearnExtensions(profiles, out _, ["m4s"]);
         // v49: SQL (#607, which came without a migration), AutoHotkey, INI, RouterOS exports and .cmd batch scripts learn
-        //      the text donut; custom claims stay put. (Schema 49 may be renumbered if another change takes it first.)
+        //      the text donut; custom claims stay put.
         if (from < 49)
             changed |= LearnExtensions(profiles, out _, ["sql", "ahk", "ini", "rsc", "cmd"]);
+        // v50: Dahua DVR recordings (.dav) learn the video donut; custom claims stay put.
+        if (from < 50)
+            changed |= LearnExtensions(profiles, out _, ["dav"]);
         return changed;
     }
 

tests/Filee.Core.Tests/DavFormatTests.cs

@@ -0,0 +1,34 @@
+// Dahua DVR recordings (.dav, #594): a read-only video source on the video donut, learned by existing libraries.
+
+using Filee.Core.Formats;
+using Filee.Core.Presets;
+using Filee.Core.Profiles;
+using Filee.Core.Settings;
+
+namespace Filee.Core.Tests;
+
+public class DavFormatTests
+{
+    [Fact]
+    public void Dav_is_a_video_filee_reads_but_never_writes()
+    {
+        var dav = FormatRegistry.Detect("ch10_main_20261005150000.DAV");
+        Assert.NotNull(dav);
+        Assert.Equal(("dav", FormatCategory.Video, false), (dav.Id, dav.Category, dav.Writable));
+        Assert.Equal("video", ProfileSelector.Select(BuiltInData.CreateProfiles(), ["camera.dav"])?.Id);
+    }
+
+    [Fact]
+    public void Version_49_libraries_learn_dav_once()
+    {
+        var presets = BuiltInData.CreatePresets();
+        var profiles = BuiltInData.CreateProfiles();
+        var video = profiles.Single(p => p.Id == "video");
+        video.Extensions.Remove("dav");
+
+        Assert.True(SettingsMigrations.ApplyToLibrary(49, presets, profiles));
+
+        Assert.Contains("dav", video.Extensions);
+        Assert.False(SettingsMigrations.ApplyToLibrary(49, presets, profiles));
+    }
+}

tests/Filee.Engines.Tests/MediaTests.cs

@@ -2,6 +2,7 @@
 // when Filee's FFmpeg is installed (`pwsh build/fetch-engines.ps1 -Only ffmpeg`; CI does not install it). Inputs are
 // generated by FFmpeg itself (test pattern + sine tone) and every output is checked with ffprobe.
 
+using System.Buffers.Binary;
 using System.Diagnostics;
 using System.Globalization;
 using System.Text.Json;
@@ -44,6 +45,117 @@
         Assert.Null(Planner().Plan("mp4", "m4s"));
     }
 
+    [Fact]
+    public void Dav_recordings_are_read_but_never_written()
+    {
+        // #594: Dahua DVR recordings, read by FFmpeg's dhav demuxer; never a target.
+        var route = Planner().Plan("dav", "mp4");
+        Assert.NotNull(route);
+        Assert.Equal("ffmpeg", Assert.Single(route.Steps).Converter.Id);
+        Assert.Null(Planner().Plan("mp4", "dav"));
+    }
+
+    [Fact]
+    public async Task A_dahua_dav_recording_converts_to_mp4()
+    {
+        // FFmpeg has no DHAV muxer, so the recording is put together here the way Dahua cameras write it: H.264 frames
+        // and G.711 A-law sound in DHAV chunks.
+        SkipUnlessInstalled();
+        var folder = fx.NewFolder();
+        var h264 = await MakeClipAsync(folder, "camera.h264", size: "160x120", audio: false,
+            extra: ["-c:v", "libx264", "-g", "25", "-bsf:v", "h264_metadata=aud=insert"]);
+        var alaw = Path.Combine(folder, "camera.alaw");
+        await RunAsync(Tools!.Value.Ffmpeg, ["-hide_banner", "-nostdin", "-v", "error", "-y", "-f", "lavfi",
+            "-i", "sine=frequency=440:sample_rate=8000:duration=2", "-ac", "1", "-f", "alaw", alaw]);
+        var dav = Path.Combine(folder, "ch01_main.dav");
+        await File.WriteAllBytesAsync(dav, Dhav.Recording(await File.ReadAllBytesAsync(h264, TestContext.Current.CancellationToken),
+            await File.ReadAllBytesAsync(alaw, TestContext.Current.CancellationToken), 160, 120), TestContext.Current.CancellationToken);
+
+        var probe = await ProcessRunner.RunAsync(Tools!.Value.Ffprobe, ["-v", "error", "-show_entries", "format=format_name", "-of", "csv=p=0", dav],
+            TimeSpan.FromMinutes(1), CancellationToken.None);
+        Assert.Equal("dhav", probe.StandardOutput.Trim());
+
+        var probed = await ProbeAsync(await ConvertAsync(dav, "mp4"));
+        var video = probed.Video;
+        Assert.NotNull(video);
+        Assert.Equal(("h264", 160, 120, 50), (video.Codec, video.Width, video.Height, video.Frames));
+        Assert.Equal("aac", probed.Audio?.Codec);
+        Assert.InRange(probed.Duration, 1.7, 2.4);
+    }
+
+    /// <summary>Dahua's DHAV container, as far as FFmpeg's dhav demuxer reads it.</summary>
+    private static class Dhav
+    {
+        /// <summary>
+        /// One video chunk per H.264 access unit (each starting with an access unit delimiter) at 25 fps, each followed
+        /// by 40 ms of 8 kHz mono A-law sound.
+        /// </summary>
+        public static byte[] Recording(byte[] annexB, byte[] alaw, int width, int height)
+        {
+            var units = AccessUnits(annexB);
+            var output = new MemoryStream();
+            for (var i = 0; i < units.Count; i++)
+            {
+                var ms = i * 40;
+                // 0x80: size in units of 8 pixels; 0x81: codec 8 (H.264) at 25 fps.
+                byte[] video = [0x80, 0, (byte)(width / 8), (byte)(height / 8), 0x81, 0, 0x08, 25];
+                Chunk(output, IsKeyFrame(units[i]) ? (byte)0xFD : (byte)0xFC, i + 1, ms, video, units[i]);
+                var sound = alaw.AsSpan().Slice(Math.Min(i * 320, alaw.Length), Math.Clamp(alaw.Length - i * 320, 0, 320));
+                // 0x83: one channel, codec 0x0E (A-law), sample rate 0 (8 kHz).
+                if (!sound.IsEmpty)
+                    Chunk(output, 0xF0, i + 1, ms, [0x83, 1, 0x0E, 0], sound);
+            }
+            return output.ToArray();
+        }
+
+        private static void Chunk(MemoryStream output, byte type, int number, int ms, ReadOnlySpan<byte> extension, ReadOnlySpan<byte> payload)
+        {
+            var length = 24 + extension.Length + payload.Length + 8;
+            var seconds = ms / 1000;
+            // Wall-clock time of the chunk: 2026-10-05 15:mm:ss.
+            var date = (uint)(seconds % 60 | seconds / 60 % 60 << 6 | 15 << 12 | 5 << 17 | 10 << 22 | (2026 - 2000) << 26);
+            Span<byte> header = stackalloc byte[24];
+            "DHAV"u8.CopyTo(header);
+            header[4] = type;
+            BinaryPrimitives.WriteInt32LittleEndian(header[8..], number);
+            BinaryPrimitives.WriteInt32LittleEndian(header[12..], length);
+            BinaryPrimitives.WriteUInt32LittleEndian(header[16..], date);
+            BinaryPrimitives.WriteUInt16LittleEndian(header[20..], (ushort)ms);
+            header[22] = (byte)extension.Length;
+            output.Write(header);
+            output.Write(extension);
+            output.Write(payload);
+            output.Write("dhav"u8);
+            Span<byte> trailer = stackalloc byte[4];
+            BinaryPrimitives.WriteInt32LittleEndian(trailer, length);
+            output.Write(trailer);
+        }
+
+        private static List<byte[]> AccessUnits(byte[] annexB)
+        {
+            byte[] delimiter = [0, 0, 0, 1, 9];
+            var starts = new List<int>();
+            for (var at = annexB.AsSpan().IndexOf(delimiter); at >= 0;)
+            {
+                starts.Add(at);
+                var next = annexB.AsSpan(at + 1).IndexOf(delimiter);
+                at = next < 0 ? -1 : at + 1 + next;
+            }
+            return starts.Select((start, i) => annexB[start..(i + 1 < starts.Count ? starts[i + 1] : annexB.Length)]).ToList();
+        }
+
+        /// <summary>An access unit with an IDR slice (NAL type 5).</summary>
+        private static bool IsKeyFrame(byte[] unit)
+        {
+            for (var i = 0; i + 3 < unit.Length; i++)
+            {
+                if (unit[i] == 0 && unit[i + 1] == 0 && unit[i + 2] == 1 && (unit[i + 3] & 0x1F) == 5)
+                    return true;
+            }
+            return false;
+        }
+    }
+
     [Fact]
     public async Task A_self_contained_m4s_converts_and_a_bare_dash_segment_is_refused()
     {
@@ -821,7 +933,7 @@
         // The coded pictures are the source's, byte for byte.
         async Task<string> Hash(string file)
         {
             var hash = await ProcessRunner.RunAsync(Tools.Value.Ffmpeg,
                 ["-hide_banner", "-v", "error", "-i", file, "-map", "0:v", "-c", "copy", "-f", "hash", "-hash", "md5", "-"],
                 TimeSpan.FromMinutes(1), CancellationToken.None);
             return hash.StandardOutput.Trim();