`TransformerAudioRenderer` reads input and passes `DecoderInputBuffer`s to the `AudioSamplePipeline`. The `AudioSamplePipeline` handles all steps from decoding to encoding. `TransformerAudioRenderer` receives `DecoderInputBuffer`s from the `AudioSamplePipeline` and passes their data to the muxer.
`AudioSamplePipeline` implements a new interface `SamplePipeline`. A pass-through pipeline will be added in a future cl.
PiperOrigin-RevId: 407555102
