docs(readme): improve demo presentation and add collapsible video

Replace the inline demo video link with an image preview and add a
collapsible section containing the full voiced demo video. Also document
the new region-selection feature available since v0.5.0 and clarify the
input description ("Utau vocal").

Author: NewComer00

README.en.md

@@ -17,11 +17,21 @@ The current version supports importing the following expression parameters:
 * `Pitch Deviation (curve)`
 * `Tension (curve)`
 
-https://github.com/user-attachments/assets/4b5b7c15-947a-4f54-b80e-a14a9eefc86b
+<p align="middle">
+  <img src="https://github.com/user-attachments/assets/268b44d4-528d-481e-acfb-3f7da7261c80" width="100%" /> 
+</p>
 
 > - *OpenUtau version used from [keirokeer/OpenUtau-DiffSinger-Lunai](https://github.com/keirokeer/OpenUtau-DiffSinger-Lunai)*
 > - *Singer model from [yousa-ling-official-production/yousa-ling-diffsinger-v1](https://github.com/yousa-ling-official-production/yousa-ling-diffsinger-v1)*
 
+> [!TIP]
+> <details>
+>   <summary><b>👉 Click to expand the full voiced demo video 👈</b></summary>
+>
+> https://github.com/user-attachments/assets/4b5b7c15-947a-4f54-b80e-a14a9eefc86b
+>
+> </details>
+
 ## ✅ Supported Platforms
 
 * Windows / Linux
@@ -42,7 +52,10 @@ When using a DiffSinger virtual singer for covers, users often already have an O
 
 ### Inputs
 
-* **Virtual vocal**: Emotionless synthesized vocal output from OpenUtau (WAV format). It's recommended to keep `Tempo` and segmentation as close to the reference vocal as possible.
+> [!TIP]
+> Starting from `v0.5.0`, users can define a selection region independently within the full audio of both the **Utau vocal** and the **Reference vocal**. The selected audio segment will be used as the final input.
+
+* **Utau vocal**: Emotionless synthesized vocal output from OpenUtau (WAV format). It's recommended to keep `Tempo` and segmentation as close to the reference vocal as possible.
 * **Reference vocal**: Original human vocal recording (WAV format). You can use tools like [UVR](https://github.com/Anjok07/ultimatevocalremovergui) to remove instrumental and reverb.
 * **Input project**: Original OpenUtau project file (USTX format).
 * **Output path**: Where the new processed project file will be saved.

README.md

@@ -17,11 +17,21 @@
 * `Pitch Deviation (curve)`
 * `Tension (curve)`
 
-https://github.com/user-attachments/assets/4b5b7c15-947a-4f54-b80e-a14a9eefc86b
+<p align="middle">
+  <img src="https://github.com/user-attachments/assets/268b44d4-528d-481e-acfb-3f7da7261c80" width="100%" /> 
+</p>
 
 > - *OpenUtau 版本来自 [keirokeer/OpenUtau-DiffSinger-Lunai](https://github.com/keirokeer/OpenUtau-DiffSinger-Lunai)*
 > - *歌手模型来自 [yousa-ling-official-production/yousa-ling-diffsinger-v1](https://github.com/yousa-ling-official-production/yousa-ling-diffsinger-v1)*
 
+> [!TIP]
+> <details>
+>   <summary><b>👉 点击展开完整有声演示视频 👈</b></summary>
+>
+> https://github.com/user-attachments/assets/4b5b7c15-947a-4f54-b80e-a14a9eefc86b
+>
+> </details>
+
 ## ✅ 支持平台
 
 * Windows / Linux
@@ -42,6 +52,9 @@ https://github.com/user-attachments/assets/4b5b7c15-947a-4f54-b80e-a14a9eefc86b
 
 ### 输入
 
+> [!TIP]
+> 从 `v0.5.0` 开始，用户可以分别在**歌姬音声**与**参考人声**的完整音频中划定选区，选区内的音频段落将作为最终输入。
+
 * **歌姬音声**：由 OpenUtau 输出的无表情虚拟歌声音频（WAV 格式）。建议节奏 (`Tempo`) 和分段尽量与参考人声一致。
 * **参考人声**：原始人声录音（WAV 格式），可使用 [UVR](https://github.com/Anjok07/ultimatevocalremovergui) 等工具去除伴奏与混响。
 * **输入工程**：原始 OpenUtau 工程文件（USTX 格式）。