CODEWITHSUNDEEP
c++caffeleveldb
Romulus Urakagi Ts'ai
Romulus Urakagi Ts'ai

Reputation: 3910

What's caffe's input format?

I'm try to use caffe for audio recognition, but can't find a document for its input format.

I want to use leveldb, thus I must create a key and a value for each record, which is a pair of label string and data byte array.

It seems that no document describes this, and after I found the value is written by Datum.SerializeToString(), I can't find where Datum is and then lost.

Does anyone know how to convert non-image records into leveldb records for caffe? Thanks!

Upvotes: 2

Views: 3283

Answers (2)

ypx
ypx

Reputation: 1459

leveldb, lmdb and HDF5 are currently the main formats for feeding data into Caffe. The MemoryData layer enable in-memory input as well, so it's possible to use whatever input format and and use Caffe's python or c++ interfaces to populate the data blobs.

If you're already set on leveldb, this discussion on caffe issues could be useful.

Below is an example for populating a leveldb with python. It requires pycaffe and plyvel. It's adapted from caffe's github issues posted by Zackory. It's not specific to images as long as you represent each example in the form of a CxHxW where any or all can be equal to 1:

import caffe

db = plyvel.DB('train_leveldb/', create_if_missing=True, error_if_exists=True, write_buffer_size=268435456)
wb = db.write_batch()
count = 0
for file in dataset:
    mat = # load numpy array from file

    # Load matrix into datum object
    datum = caffe.io.array_to_datum(mat)

    wb.put('%08d_%s' % (count, file), datum.SerializeToString())

    count += 1

    # Write to db in regular intervals
    if count % 1000 == 0:
        # Write batch of images to database
        wb.write()
        del wb
        wb = db.write_batch()

    # Write last batch of images
    if count % 1000 != 0:
        wb.write()

I find constructing lmdb a lot simpler. lmdb example here.

Upvotes: 3

Mikael Rousson
Mikael Rousson

Reputation: 2277

The Datum object is defined with protobuf. See here: https://github.com/BVLC/caffe/blob/master/src/caffe/proto/caffe.proto#L30-L41

It generates a file caffe.pb.h in .build_release/src/caffe/proto with the class Datum. You can have a look there to understand how this object works.

Upvotes: 1

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