Merge pull request #201797 from sally-baolian/patch-31

Update long-audio-api.md

Author: PRMerger-2

articles/cognitive-services/Speech-Service/long-audio-api.md

@@ -35,6 +35,9 @@ When preparing your text file, make sure it:
   * For plain text, each paragraph is separated by hitting **Enter/Return**. See [plain text input example](https://github.com/Azure-Samples/Cognitive-Speech-TTS/blob/master/CustomVoice-API-Samples/Java/en-US.txt).
   * For SSML text, each SSML piece is considered a paragraph. Separate SSML pieces by different paragraphs. See [SSML text input example](https://github.com/Azure-Samples/Cognitive-Speech-TTS/blob/master/CustomVoice-API-Samples/Java/SSMLTextInputSample.txt).
 
+> [!NOTE]
+> When using SSML text, be sure to use the [supported SSML elements](speech-synthesis-markup.md?tabs=csharp#supported-ssml-elements) except the `audio` and `mstts:backgroundaudio` elements. The `audio` and `mstts:backgroundaudio` elements are not supported by Long Audio API. The `audio` element will be ignored without any error message. The `mstts:backgroundaudio` element will cause the systhesis task failure. If your synthesis task fails, download the audio result (.zip file) and check the error report with suffix name "err.txt" within the zip file for details.
+
 ## Sample code
 
 The rest of this page focuses on Python, but sample code for the Long Audio API is available on GitHub for the following programming languages:

articles/cognitive-services/Speech-Service/speech-synthesis-markup.md

@@ -771,6 +771,9 @@ Any audio included in the SSML document must meet these requirements:
 * The combined total time for all text and audio files in a single response can't exceed 600 seconds.
 * The audio must not contain any customer-specific or other sensitive information.
 
+> [!NOTE]
+> The 'audio' element is not supported by the Long Audio API.
+
 **Syntax**
 
 ```xml
@@ -807,6 +810,9 @@ If the background audio provided is shorter than the text-to-speech or the fade
 
 Only one background audio file is allowed per SSML document. You can intersperse `audio` tags within the `voice` element to add more audio to your SSML document.
 
+> [!NOTE]
+> The `mstts:backgroundaudio` element is not supported by the Long Audio API.
+
 **Syntax**
 
 ```xml