feat: Add video decoder selection and MPEG/H263 support

Introduce a VideoDecoderSelection setting and UI to cycle/choose preferred decoder (Auto, H.264, MPEG-2, H.263+). Persist and parse the new streaming.video_decoder setting, include it in settings initialization/persistence, and expose the choice in the settings UI and status messages. Advertise supported Moonlight video formats based on the preference and pass that to the session startup; update the FFmpeg backend to select and log the appropriate decoder (mpeg2/h263/h264), improve error messages, and expose the active decoder name to stats/overlays. Enable required FFmpeg parsers/decoders and update the ffmpeg profile signature; add/update unit tests and bump the moonlight-common-c submodule.

Author: ReenigneArcher

cmake/moonlight-dependencies.cmake

@@ -82,7 +82,7 @@ function(_moonlight_compute_ffmpeg_signature out_var nxdk_dir ffmpeg_source_dir)
     set(signature_inputs
             "FFMPEG_REVISION=${ffmpeg_revision}"
             "NXDK_DIR=${nxdk_dir}"
-            "FFMPEG_PROFILE=h264-opus-xbox"
+            "FFMPEG_PROFILE=h264-mpeg2-h263-opus-xbox"
             "FFMPEG_TARGET_OS=none"
             "FFMPEG_ARCH=x86"
             "FFMPEG_CC_WRAPPER_SHA256=${ffmpeg_cc_wrapper_hash}"
@@ -201,7 +201,13 @@ function(_moonlight_get_ffmpeg_configure_args out_var)
             --enable-swscale
             --enable-swresample
             --enable-parser=h264
+            --enable-parser=h263
+            --enable-parser=mpegvideo
             --enable-decoder=h264
+            --enable-decoder=h263
+            --enable-decoder=h263i
+            --enable-decoder=h263p
+            --enable-decoder=mpeg2video
             --enable-decoder=opus)
 
     set(${out_var} "${ffmpeg_configure_args}" PARENT_SCOPE)

src/app/client_state.cpp

@@ -32,6 +32,12 @@ namespace {
   constexpr int DEFAULT_STREAM_BITRATE_KBPS = 1000;
   constexpr std::array<int, 6> STREAM_FRAMERATE_OPTIONS {15, 20, 24, 25, 30, 60};
   constexpr std::array<int, 9> STREAM_BITRATE_OPTIONS {500, 750, 1000, 1500, 2000, 2500, 3000, 4000, 5000};
+  constexpr std::array<app::VideoDecoderSelection, 4> VIDEO_DECODER_OPTIONS {
+    app::VideoDecoderSelection::autoDetect,
+    app::VideoDecoderSelection::h264,
+    app::VideoDecoderSelection::mpeg2,
+    app::VideoDecoderSelection::h263p,
+  };
 
   /**
    * @brief Describes the keypad characters available for the active add-host field.
@@ -144,6 +150,27 @@ namespace {
     return std::to_string(videoMode.width) + "x" + std::to_string(videoMode.height);
   }
 
+  /**
+   * @brief Return the settings label for one video decoder preference.
+   *
+   * @param selection Decoder preference to describe.
+   * @return User-facing decoder preference label.
+   */
+  const char *video_decoder_selection_label(app::VideoDecoderSelection selection) {
+    switch (selection) {
+      case app::VideoDecoderSelection::autoDetect:
+        return "Auto";
+      case app::VideoDecoderSelection::h264:
+        return "H.264";
+      case app::VideoDecoderSelection::mpeg2:
+        return "MPEG-2/H.262";
+      case app::VideoDecoderSelection::h263p:
+        return "H.263+";
+    }
+
+    return "Auto";
+  }
+
   /**
    * @brief Return the selected stream-resolution index inside the detected mode list.
    *
@@ -213,6 +240,22 @@ namespace {
     state.settings.streamBitrateKbps = STREAM_BITRATE_OPTIONS[nextIndex];
   }
 
+  /**
+   * @brief Advance the preferred video decoder to the next supported option.
+   *
+   * @param state Current client state containing the preferred decoder.
+   */
+  void cycle_video_decoder(app::ClientState &state) {
+    const auto current = std::find(VIDEO_DECODER_OPTIONS.begin(), VIDEO_DECODER_OPTIONS.end(), state.settings.videoDecoder);
+    if (current == VIDEO_DECODER_OPTIONS.end()) {
+      state.settings.videoDecoder = app::VideoDecoderSelection::autoDetect;
+      return;
+    }
+
+    const std::size_t nextIndex = (static_cast<std::size_t>(std::distance(VIDEO_DECODER_OPTIONS.begin(), current)) + 1U) % VIDEO_DECODER_OPTIONS.size();
+    state.settings.videoDecoder = VIDEO_DECODER_OPTIONS[nextIndex];
+  }
+
   std::string pairing_reset_endpoint_key(std::string_view address, uint16_t port) {
     return app::normalize_ipv4_address(address) + ":" + std::to_string(app::effective_host_port(port));
   }
@@ -544,6 +587,12 @@ namespace {
             "Cycle through the preferred video bitrate. Lower bitrates reduce bandwidth use and can help when running Sunshine and xemu on the same NATed host.",
             true,
           },
+          {
+            "cycle-video-decoder",
+            std::string("Video Decoder: ") + video_decoder_selection_label(state.settings.videoDecoder),
+            "Choose automatic codec negotiation or force one FFmpeg video decoder for new streams.",
+            true,
+          },
           {
             "toggle-play-audio-on-pc",
             std::string("Play Audio on PC: ") + (state.settings.playAudioOnPc ? "On" : "Off"),
@@ -1405,6 +1454,7 @@ namespace app {
     state.settings.xemuConsoleLoggingLevel = logging::LogLevel::none;
     state.settings.streamFramerate = DEFAULT_STREAM_FRAMERATE;
     state.settings.streamBitrateKbps = DEFAULT_STREAM_BITRATE_KBPS;
+    state.settings.videoDecoder = VideoDecoderSelection::autoDetect;
     state.settings.playAudioOnPc = false;
     state.settings.showPerformanceStats = false;
     state.settings.playAudioOnXbox = true;
@@ -1996,6 +2046,14 @@ namespace app {
       rebuild_menu(state, "cycle-stream-bitrate");
       return;
     }
+    if (detailUpdate.activatedItemId == "cycle-video-decoder") {
+      cycle_video_decoder(state);
+      state.settings.dirty = true;
+      update->persistence.settingsChanged = true;
+      state.shell.statusMessage = std::string("Video decoder set to ") + video_decoder_selection_label(state.settings.videoDecoder);
+      rebuild_menu(state, "cycle-video-decoder");
+      return;
+    }
     if (detailUpdate.activatedItemId == "toggle-play-audio-on-pc") {
       state.settings.playAudioOnPc = !state.settings.playAudioOnPc;
       state.settings.dirty = true;

src/app/client_state.h

@@ -65,6 +65,16 @@ namespace app {
     right,  ///< Dock the log viewer on the right side of the split layout.
   };
 
+  /**
+   * @brief Video decoder preference applied to new streaming sessions.
+   */
+  enum class VideoDecoderSelection {
+    autoDetect,  ///< Let moonlight-common-c negotiate the best mutually supported video format.
+    h264,  ///< Force H.264 video decode.
+    mpeg2,  ///< Force MPEG-2/H.262 video decode.
+    h263p,  ///< Force H.263+ video decode.
+  };
+
   /**
    * @brief Focus areas used by the two-pane settings screen.
    */
@@ -321,6 +331,7 @@ namespace app {
     bool preferredVideoModeSet = false;  ///< True when preferredVideoMode contains a user-selected or default mode.
     int streamFramerate = 30;  ///< Preferred stream frame rate in frames per second.
     int streamBitrateKbps = 1000;  ///< Preferred stream bitrate in kilobits per second.
+    VideoDecoderSelection videoDecoder = VideoDecoderSelection::autoDetect;  ///< Preferred video decoder for new streams.
     bool playAudioOnPc = false;  ///< True when the host PC should continue local audio playback during streaming.
     bool showPerformanceStats = false;  ///< True when stream telemetry should be shown after streaming ends.
     bool playAudioOnXbox = true;  ///< True when the Xbox should decode and play streamed audio locally.

src/app/settings_storage.cpp

@@ -127,6 +127,27 @@ namespace {
     return "full";
   }
 
+  /**
+   * @brief Convert a decoder preference to the persisted TOML token.
+   *
+   * @param selection Decoder preference to serialize.
+   * @return Stable lowercase settings value.
+   */
+  const char *video_decoder_selection_text(app::VideoDecoderSelection selection) {
+    switch (selection) {
+      case app::VideoDecoderSelection::autoDetect:
+        return "auto";
+      case app::VideoDecoderSelection::h264:
+        return "h264";
+      case app::VideoDecoderSelection::mpeg2:
+        return "mpeg2";
+      case app::VideoDecoderSelection::h263p:
+        return "h263p";
+    }
+
+    return "auto";
+  }
+
   bool try_parse_logging_level(std::string_view text, logging::LogLevel *level) {
     const std::string normalized = ascii_lowercase(text);
     if (normalized == "trace") {
@@ -193,6 +214,43 @@ namespace {
     return false;
   }
 
+  /**
+   * @brief Parse a decoder preference from the persisted TOML token.
+   *
+   * @param text Settings value to parse.
+   * @param selection Receives the parsed decoder preference on success.
+   * @return True when @p text is a supported decoder preference.
+   */
+  bool try_parse_video_decoder_selection(std::string_view text, app::VideoDecoderSelection *selection) {
+    const std::string normalized = ascii_lowercase(text);
+    if (normalized == "auto") {
+      if (selection != nullptr) {
+        *selection = app::VideoDecoderSelection::autoDetect;
+      }
+      return true;
+    }
+    if (normalized == "h264" || normalized == "h.264") {
+      if (selection != nullptr) {
+        *selection = app::VideoDecoderSelection::h264;
+      }
+      return true;
+    }
+    if (normalized == "mpeg2" || normalized == "mpeg-2" || normalized == "h262" || normalized == "h.262") {
+      if (selection != nullptr) {
+        *selection = app::VideoDecoderSelection::mpeg2;
+      }
+      return true;
+    }
+    if (normalized == "h263p" || normalized == "h.263p" || normalized == "h263+" || normalized == "h.263+") {
+      if (selection != nullptr) {
+        *selection = app::VideoDecoderSelection::h263p;
+      }
+      return true;
+    }
+
+    return false;
+  }
+
   void append_invalid_value_warning(std::vector<std::string> *warnings, const std::string &filePath, std::string_view keyPath, std::string_view valueText) {
     if (warnings == nullptr) {
       return;
@@ -263,6 +321,34 @@ namespace {
     append_invalid_value_warning(warnings, filePath, "ui.log_viewer_placement", "<non-string>");
   }
 
+  /**
+   * @brief Load one decoder preference setting when present.
+   *
+   * @param settingNode TOML node to parse.
+   * @param filePath Settings file path used in warnings.
+   * @param selection Receives the parsed decoder preference on success.
+   * @param warnings Warning collection updated for invalid values.
+   */
+  void load_video_decoder_selection_setting(
+    toml::node_view<const toml::node> settingNode,
+    const std::string &filePath,
+    app::VideoDecoderSelection *selection,
+    std::vector<std::string> *warnings
+  ) {
+    if (!settingNode) {
+      return;
+    }
+
+    if (const auto videoDecoderText = settingNode.value<std::string>(); videoDecoderText) {
+      if (!try_parse_video_decoder_selection(*videoDecoderText, selection)) {
+        append_invalid_value_warning(warnings, filePath, "streaming.video_decoder", *videoDecoderText);
+      }
+      return;
+    }
+
+    append_invalid_value_warning(warnings, filePath, "streaming.video_decoder", "<non-string>");
+  }
+
   /**
    * @brief Load one integer settings value when present.
    *
@@ -346,6 +432,8 @@ namespace {
     content += "# Preferred streaming parameters.\n";
     content += std::string("fps = ") + std::to_string(settings.streamFramerate) + "\n";
     content += std::string("bitrate_kbps = ") + std::to_string(settings.streamBitrateKbps) + "\n";
+    content += "# Video decoder preference. Use auto to keep normal host negotiation.\n";
+    content += std::string("video_decoder = \"") + video_decoder_selection_text(settings.videoDecoder) + "\"\n";
     content += std::string("play_audio_on_pc = ") + (settings.playAudioOnPc ? "true" : "false") + "\n";
     content += std::string("play_audio_on_xbox = ") + (settings.playAudioOnXbox ? "true" : "false") + "\n";
     content += "# Show stream telemetry after streaming ends.\n";
@@ -392,7 +480,7 @@ namespace {
   void inspect_streaming_keys(const toml::table &streamingTable, const std::string &filePath, app::LoadAppSettingsResult *result) {
     for (const auto &[rawKey, node] : streamingTable) {
       const std::string key(rawKey.str());
-      if (key == "video_width" || key == "video_height" || key == "video_bpp" || key == "video_refresh" || key == "video_mode_selected" || key == "fps" || key == "bitrate_kbps" || key == "play_audio_on_pc" || key == "play_audio_on_xbox" || key == "show_performance_stats") {
+      if (key == "video_width" || key == "video_height" || key == "video_bpp" || key == "video_refresh" || key == "video_mode_selected" || key == "fps" || key == "bitrate_kbps" || key == "video_decoder" || key == "play_audio_on_pc" || key == "play_audio_on_xbox" || key == "show_performance_stats") {
         continue;
       }
 
@@ -490,6 +578,7 @@ namespace app {
     load_boolean_setting(settingsTable["streaming"]["video_mode_selected"], filePath, "streaming.video_mode_selected", &result.settings.preferredVideoModeSet, &result.warnings);
     load_integer_setting(settingsTable["streaming"]["fps"], filePath, "streaming.fps", &result.settings.streamFramerate, &result.warnings);
     load_integer_setting(settingsTable["streaming"]["bitrate_kbps"], filePath, "streaming.bitrate_kbps", &result.settings.streamBitrateKbps, &result.warnings);
+    load_video_decoder_selection_setting(settingsTable["streaming"]["video_decoder"], filePath, &result.settings.videoDecoder, &result.warnings);
     load_boolean_setting(settingsTable["streaming"]["play_audio_on_pc"], filePath, "streaming.play_audio_on_pc", &result.settings.playAudioOnPc, &result.warnings);
     load_boolean_setting(settingsTable["streaming"]["play_audio_on_xbox"], filePath, "streaming.play_audio_on_xbox", &result.settings.playAudioOnXbox, &result.warnings);
     load_boolean_setting(settingsTable["streaming"]["show_performance_stats"], filePath, "streaming.show_performance_stats", &result.settings.showPerformanceStats, &result.warnings);

src/app/settings_storage.h

@@ -24,6 +24,7 @@ namespace app {
     bool preferredVideoModeSet = false;  ///< True when preferredVideoMode contains a saved user preference.
     int streamFramerate = 30;  ///< Preferred stream frame rate in frames per second.
     int streamBitrateKbps = 1000;  ///< Preferred stream bitrate in kilobits per second.
+    app::VideoDecoderSelection videoDecoder = app::VideoDecoderSelection::autoDetect;  ///< Preferred video decoder for new streams.
     bool playAudioOnPc = false;  ///< True when the host PC should continue local audio playback during streaming.
     bool showPerformanceStats = false;  ///< True when stream telemetry should be shown after streaming ends.
     bool playAudioOnXbox = true;  ///< True when the Xbox should decode and play streamed audio locally.

src/main.cpp

@@ -44,6 +44,7 @@ namespace {
     state.settings.preferredVideoModeSet = settings.preferredVideoModeSet;
     state.settings.streamFramerate = settings.streamFramerate;
     state.settings.streamBitrateKbps = settings.streamBitrateKbps;
+    state.settings.videoDecoder = settings.videoDecoder;
     state.settings.playAudioOnPc = settings.playAudioOnPc;
     state.settings.showPerformanceStats = settings.showPerformanceStats;
     state.settings.playAudioOnXbox = settings.playAudioOnXbox;

src/startup/video_mode.cpp

@@ -39,9 +39,13 @@ namespace startup {
       return left.width == right.width && left.height == right.height;
     }
 
+    int stream_video_mode_area(const VIDEO_MODE &videoMode) {
+      return videoMode.width * videoMode.height;
+    }
+
     bool is_smaller_video_mode(const VIDEO_MODE &left, const VIDEO_MODE &right) {
-      const int leftArea = left.width * left.height;
-      if (const int rightArea = right.width * right.height; leftArea != rightArea) {
+      const int leftArea = stream_video_mode_area(left);
+      if (const int rightArea = stream_video_mode_area(right); leftArea != rightArea) {
         return leftArea < rightArea;
       }
       return left.width < right.width;