question

Simon avatar image
Simon asked

Does APLA and layering of sound cause any sound degradation? (For example, over-modulation)

Hello! Like the title says, could APLA and layering of multiple large sound files cause any sound degradation?

I've got an APLA document with a sequencer that contains a single audio file, some silence then a 2 item mixer. The mixer has two items, a sequencer with multple items putting together dynamically assembled voiceover and a music bed that goes under the voice over (see code below)

The audio files are high quality WAVs (a mix of 16-bit and 8-bit where we had to get under the 10MB file size) so they're relatively large compared to mp3.

When it plays out at runtime, the audio sounds over modulated. Is there anything I can do about this? Separately the audio files play out perfectly, it's just together there's an issue.

I did wonder if there's a limit on nesting sequencers/ mixers or a cumulative effect of nesting with multiple audio files. But I can't find anything in the docs.

So here I am asking the question. I can't share the audio files because confidentiality agreement.

{
    "type": "Alexa.Presentation.APLA.RenderDocument",
    "token": "1",
    "document": {
      "version": "0.91",
      "type": "APLA",
      "mainTemplate": {
        "parameters": [
          "payload"
            ],
         "items": [
                {
                "type": "Sequencer",
                "items": [
                    {
                        "type": "Audio",
                        "source": "${payload.audioURLs.guessURL}"
                    },
                    {
                        "type": "Silence",
                        "duration": 1000
                    },
                    {
                        "type": "Mixer",
                        "filter": {
                            "type": "FadeOut",
                            "duration": 2000
                        },
                        "items": [
                            {
                                "type": "Sequencer",
                                "items": [
                                    {
                                        "type": "Silence",
                                        "duration": 6000
                                    },
                                    {
                                        "type": "Audio",
                                        "source": "${payload.audioURLs.congratulationsURL}"
                                    },
                                    {
                                        "type": "Silence",
                                        "duration": 2000
                                    }
                                    
                                ]
                            },
                            {
                                "type": "Audio",
                                "source": "${payload.audioURLs.correctBedURL}",
                                "duration": "trimToParent"
                            }
                        ]
                    },
                    {
                        "type": "Audio",
                        "source": "${payload.audioURLs.playAgainURL}"
                    }
                    
                ]
                }
            ]
        }
    }
}
audioalexa presentation languageaudio playback
10 |5000 characters needed characters left characters exceeded

Up to 2 attachments (including images) can be used with a maximum of 512.0 KiB each and 1.0 MiB total.

1 Answer

Simon avatar image
Simon answered

the answer was our levels - once we knocked the level of the audio back a bit, it worked just fine!

10 |5000 characters needed characters left characters exceeded

Up to 2 attachments (including images) can be used with a maximum of 512.0 KiB each and 1.0 MiB total.