There are some things to be aware of during this stage of the process.
Protocol buffer and memory mappable file formats¶
By default, 🐸STT will export the trained model as a
.pb file, such as:
$ sudo ls -las volumes/stt-data/_data/exported-model 4 drwxr-xr-x 2 root root 4096 Feb 1 22:13 . 4 drwxr-xr-x 6 root root 4096 Feb 1 22:23 .. 4 -rwxr-xr-x 1 root root 1586 Feb 1 22:13 author_model_0.0.1.md 184488 -rwxr-xr-x 1 root root 188915369 Feb 1 22:13 output_graph.pb
.pb file is a protocol buffer file. Protocol buffer is a widely used file format for trained models, but it has a significant downsides. It is not memory mappable. Memory mappable files can be referenced by the operating system using a file descriptor, and they consume far less memory than non-memory-mappable files. Protocol buffer files also tend to be much larger than memory-mappable files.
Most inference libraries, such as TensorFlow, require a memory-mappable format.
There are two formats in particular that you should be familiar with.
Exporting a memory mappable protocol buffer file with
graphdef tool which is built in to TensorFlow (but deprecated in TensorFlow 2.3), you can export a memory-mappable protocol buffer file using the following commands:
convert_graphdef_memmapped_format --in_graph=output_graph.pb --out_graph=output_graph.pbmm
--in_graph is a path to your
.pb file and
--out_graph is a path to the exported memory-mappable protocol buffer file.
root@12a4ee8ce1ed:/STT# ./convert_graphdef_memmapped_format \ --in_graph="persistent-data/exported-model/output_graph.pb" \ --out_graph="persistent-data/exported-model/output_graph.pbmm" 2021-02-03 21:13:09.516709: W tensorflow/core/framework/cpu_allocator_impl.cc:81] Allocation of 134217728 exceeds 10% of system memory. 2021-02-03 21:13:09.647395: I tensorflow/contrib/util/convert_graphdef_memmapped_format_lib.cc:171] Converted 7 nodes
Be aware that this file format is likely to be deprecated in the future. We strongly recommend the use of
Exporting a tflite model¶
tflite engine (more information on tflite) is designed to allow inference on mobile, IoT and embedded devices. If you have not yet trained a model, and you want to export a model compatible with
tflite, you will need to use the
--export_tflite flags with the
train.py script. For example:
python3 train.py \ --train_files stt-data/cv-corpus-6.1-2020-12-11/id/clips/train.csv \ --dev_files stt-data/cv-corpus-6.1-2020-12-11/id/clips/dev.csv \ --test_files stt-data/cv-corpus-6.1-2020-12-11/id/clips/test.csv \ --checkpoint_dir stt-data/checkpoints \ --export_dir stt-data/exported-model \ --export_tflite
If you have already trained a model, and wish to export to
tflite format, you can re-export it by specifying the same
checkpoint_dir that you used for training, and by passing the
Here is an example:
python3 train.py \ --checkpoint_dir persistent-data/checkpoints \ --export_dir persistent-data/exported-model \ --export_tflite I Loading best validating checkpoint from persistent-data/checkpoints-1feb2021-id/best_dev-34064 I Loading variable from checkpoint: cudnn_lstm/rnn/multi_rnn_cell/cell_0/cudnn_compatible_lstm_cell/bias I Loading variable from checkpoint: cudnn_lstm/rnn/multi_rnn_cell/cell_0/cudnn_compatible_lstm_cell/kernel I Loading variable from checkpoint: layer_1/bias I Loading variable from checkpoint: layer_1/weights I Loading variable from checkpoint: layer_2/bias I Loading variable from checkpoint: layer_2/weights I Loading variable from checkpoint: layer_3/bias I Loading variable from checkpoint: layer_3/weights I Loading variable from checkpoint: layer_5/bias I Loading variable from checkpoint: layer_5/weights I Loading variable from checkpoint: layer_6/bias I Loading variable from checkpoint: layer_6/weights I Models exported at persistent-data/exported-model I Model metadata file saved to persistent-data/exported-model/author_model_0.0.1.md. Before submitting the exported model for publishing make sure all information in the metadata file is correct, and complete the URL fields. root@0913858a2868:/STT/persistent-data/exported-model# ls -las total 415220 4 drwxr-xr-x 2 root root 4096 Feb 3 22:42 . 4 drwxr-xr-x 7 root root 4096 Feb 3 21:54 .. 4 -rwxr-xr-x 1 root root 1582 Feb 3 22:42 author_model_0.0.1.md 184488 -rwxr-xr-x 1 root root 188915369 Feb 1 11:13 output_graph.pb 184496 -rw-r--r-- 1 root root 188916323 Feb 3 21:13 output_graph.pbmm 46224 -rw-r--r-- 1 root root 47332112 Feb 3 22:42 output_graph.tflite
For more information on exporting a
tflite model, please consult the documentation.