Make single and multi reader behave the same, in particular for audio

Summary: We found that SyncVRSReader doesn't handle audio the same when used with a single or a multi reader, which is caused by a different implementation between the two. This diff fixes the issue and adds a test to prove that audio is handled the same.

Reviewed By: finik

Differential Revision: D68034361

fbshipit-source-id: b8a70dd046541b81ecd4f23d568a0960cdffb517

csrc/reader/MultiVRSReader.cpp

@@ -176,10 +176,8 @@ bool OssMultiVRSReader::MultiVRSReaderStreamPlayer::setBlock(
       if (contentBlock.getContentType() == ContentType::IMAGE) {
         // for raw images, we return a structured array based on the image format
         block.structuredArray = (contentBlock.image().getImageFormat() == vrs::ImageFormat::RAW);
-      } else if (contentBlock.getContentType() != ContentType::AUDIO) {
-        block.structuredArray = true;
       } else {
-        block.structuredArray = false;
+        block.structuredArray = (contentBlock.getContentType() == ContentType::AUDIO);
       }
     } else if (imageConversion == ImageConversion::RawBuffer) {
       // default handling