Add nightly build installation code snippet to prototype feature tutorials (#2325)

Summary:
Tutorial notebooks that leverage TorchAudio prototype features don't run as-is on Google Colab due to its runtime's not having nightly builds pre-installed. To make it easier for users to run said notebooks in Colab, this PR adds a code block that installs nightly Pytorch and TorchAudio builds as a comment that users can copy and run locally.

Pull Request resolved: https://github.com/pytorch/audio/pull/2325

Reviewed By: xiaohui-zhang

Differential Revision: D35597753

Pulled By: hwangjeff

fbshipit-source-id: 59914e492ad72e31c0136a48cd88d697e8ea5f6c

examples/tutorials/asr_inference_with_ctc_decoder_tutorial.py

@@ -72,6 +72,26 @@ import matplotlib.pyplot as plt
 import torch
 import torchaudio
 
+try:
+    import torchaudio.prototype.ctc_decoder
+except ModuleNotFoundError:
+    try:
+        import google.colab
+
+        print(
+            """
+            To enable running this notebook in Google Colab, install nightly
+            torch and torchaudio builds by adding the following code block to the top
+            of the notebook before running it:
+
+            !pip3 uninstall -y torch torchvision torchaudio
+            !pip3 install --pre torch torchvision torchaudio --extra-index-url https://download.pytorch.org/whl/nightly/cpu
+            """
+        )
+    except ModuleNotFoundError:
+        pass
+    raise
+
 
 ######################################################################
 # Acoustic Model and Data

examples/tutorials/device_asr.py

@@ -10,7 +10,7 @@ on laptop.
 
 .. note::
 
-   This tutorial requires prototype Streaming API and ffmpeg>=4.1.
+   This tutorial requires prototype Streaming API, ffmpeg>=4.1, and SentencePiece.
 
    Prototype features are not part of binary releases, but available in
    nightly build. Please refer to https://pytorch.org for installing
@@ -20,6 +20,8 @@ on laptop.
    ``conda install -c anaconda ffmpeg`` will install
    the required libraries.
 
+   You can install SentencePiece by running ``pip install sentencepiece``.
+
 .. note::
 
    This tutorial was tested on MacBook Pro and Dynabook with Windows 10.

examples/tutorials/online_asr_tutorial.py

@@ -13,8 +13,8 @@ to perform online speech recognition.
 #
 # .. note::
 #
-#    This tutorial requires torchaudio with prototype features and
-#    FFmpeg libraries (>=4.1).
+#    This tutorial requires torchaudio with prototype features,
+#    FFmpeg libraries (>=4.1), and SentencePiece.
 #
 #    torchaudio prototype features are available on nightly builds.
 #    Please refer to https://pytorch.org/get-started/locally/
@@ -30,13 +30,7 @@ to perform online speech recognition.
 #    ``conda install -c anaconda ffmpeg`` will install
 #    the required libraries.
 #
-#    When running this tutorial in Google Colab, the following
-#    command should do.
-#
-#    .. code::
-#
-#       !add-apt-repository -y ppa:savoury1/ffmpeg4
-#       !apt-get -qq install -y ffmpeg
+#    You can install SentencePiece by running ``pip install sentencepiece``.
 
 ######################################################################
 # 1. Overview
@@ -59,10 +53,32 @@ import IPython
 import torch
 import torchaudio
 
+try:
+    from torchaudio.prototype.io import Streamer
+except ModuleNotFoundError:
+    try:
+        import google.colab
+
+        print(
+            """
+            To enable running this notebook in Google Colab, install nightly
+            torch and torchaudio builds and the requisite third party libraries by
+            adding the following code block to the top of the notebook before running it:
+
+            !pip3 uninstall -y torch torchvision torchaudio
+            !pip3 install --pre torch torchaudio --extra-index-url https://download.pytorch.org/whl/nightly/cpu
+            !pip3 install sentencepiece
+            !add-apt-repository -y ppa:savoury1/ffmpeg4
+            !apt-get -qq install -y ffmpeg
+            """
+        )
+    except ModuleNotFoundError:
+        pass
+    raise
+
 print(torch.__version__)
 print(torchaudio.__version__)
 
-from torchaudio.prototype.io import Streamer
 
 ######################################################################
 # 3. Construct the pipeline

examples/tutorials/streaming_api_tutorial.py

@@ -29,13 +29,6 @@ libavfilter provides.
 #    ``conda install -c anaconda ffmpeg`` will install
 #    the required libraries.
 #
-#    When running this tutorial in Google Colab, the following
-#    command should do.
-#
-#    .. code::
-#
-#       !add-apt-repository -y ppa:savoury1/ffmpeg4
-#       !apt-get -qq install -y ffmpeg
 
 ######################################################################
 # 1. Overview
@@ -77,7 +70,28 @@ import IPython
 import matplotlib.pyplot as plt
 import torch
 import torchaudio
-from torchaudio.prototype.io import Streamer
+
+try:
+    from torchaudio.prototype.io import Streamer
+except ModuleNotFoundError:
+    try:
+        import google.colab
+
+        print(
+            """
+            To enable running this notebook in Google Colab, install nightly
+            torch and torchaudio builds and the requisite third party libraries by
+            adding the following code block to the top of the notebook before running it:
+
+            !pip3 uninstall -y torch torchvision torchaudio
+            !pip3 install --pre torch torchaudio --extra-index-url https://download.pytorch.org/whl/nightly/cpu
+            !add-apt-repository -y ppa:savoury1/ffmpeg4
+            !apt-get -qq install -y ffmpeg
+            """
+        )
+    except ModuleNotFoundError:
+        pass
+    raise
 
 print(torch.__version__)
 print(torchaudio.__version__)