MXNet provides a Python utility to create RecordIO packages of data that are supported by framework’s data iterators.
Little detail, the im2rec.py doesn’t support .png files, unless you manually adjust the script and add it as allowed extensions.
In order to create a rec file, you first need to make a list of files using this command:
python \\mxnet-master\tools\im2rec.py --list 1 --recursive 1 --num-thread 4 --train-ratio 0.7 --test-ratio 0.2 prefix frames
--list 1 ==> tells the script to create the .lst files
--num-thread 4 ==> runs script in parallel
--train-ratio 0.7 ==> will split the data set between several list files
--test-ratio 0.2 ==> it will make sure that 20 percent of the data will be used in the test set.
After you get .lst files, lets create a record set.
Record objects will be about the same size as the data that being used for the objects.
python \\mxnet-master\tools\im2rec.py --num-thread 4 --quality 80 prefix frames
here we eliminating –list argument so the script will be working on .rec files.
At the end of its execution, it should display something like
time: 0.0130000114441 count: 0 time: 3.01699995995 count: 1000 time: 2.83000016212 count: 2000
and in the folder where you have your dataset you will see files
prefix_test.rec prefix_test.lst prefix_test.val
and same for train and validation sets.