Refine the documentation of im2rec

docs/faq/recordio.md

@@ -6,35 +6,39 @@ RecordIO implements a file format for a sequence of records. We recommend storin
 * Packing data together allows continuous reading on the disk.
 * RecordIO has a simple way to partition, simplifying distributed setting. We provide an example later.
 
-We provide the [im2rec tool](https://github.com/dmlc/mxnet/blob/master/tools/im2rec.cc) so you can create an Image RecordIO dataset by yourself. The following walkthrough shows you how.
+We provide the [im2rec tool](https://github.com/dmlc/mxnet/blob/master/tools/im2rec.cc) so you can create an Image RecordIO dataset by yourself. The following walkthrough shows you how. Note that there is python version of [im2rec tool](https://github.com/apache/incubator-mxnet/blob/master/tools/im2rec.py) and [example](https://mxnet.incubator.apache.org/tutorials/basic/data.html) using real-world data.
 
 ### Prerequisites
+
 Download the data. You don't need to resize the images manually. You can use ```im2rec``` to resize them automatically. For details, see the "Extension: Using Multiple Labels for a Single Image," later in this topic.
 
 ### Step 1. Make an Image List File
+
+* Note that the im2rec.py provide a param `--list` to generate the list for you but im2rec.cc doesn't support it.
+
 After you download the data, you need to make an image list file.  The format is:
 
 ```
 integer_image_index \t label_index \t path_to_image
 ```
 Typically, the program takes the list of names of all of the images, shuffles them, then separates them into two lists: a training filename list and a testing filename list. Write the list in the right format.
-
 This is an example file:
 
 ```bash
-95099  464     n04467665_17283.JPEG
-10025081        412     ILSVRC2010_val_00025082.JPEG
-74181   789     n01915811_2739.JPEG
-10035553        859     ILSVRC2010_val_00035554.JPEG
-10048727        929     ILSVRC2010_val_00048728.JPEG
-94028   924     n01980166_4956.JPEG
-1080682 650     n11807979_571.JPEG
-972457  633     n07723039_1627.JPEG
-7534    11      n01630670_4486.JPEG
-1191261 249     n12407079_5106.JPEG
+95099  464.000000     n04467665_17283.JPEG
+10025081        412.000000     ILSVRC2010_val_00025082.JPEG
+74181   789.000000     n01915811_2739.JPEG
+10035553        859.000000     ILSVRC2010_val_00035554.JPEG
+10048727        929.000000     ILSVRC2010_val_00048728.JPEG
+94028   924.000000     n01980166_4956.JPEG
+1080682 650.000000     n11807979_571.JPEG
+972457  633.000000     n07723039_1627.JPEG
+7534    11.000000      n01630670_4486.JPEG
+1191261 249.000000     n12407079_5106.JPEG
 ```
 
 ### Step 2. Create the Binary File
+
 To generate a binary image, use `im2rec` in the tool folder. `im2rec` takes the path of the `_image list file_` you generated, the `_root path_` of the images, and the `_output file path_` as input. This process usually takes several hours, so be patient.
 
 Sample command:

docs/tutorials/basic/data.md

@@ -315,6 +315,8 @@ print(mx.recordio.unpack_img(s))
 You can also convert raw images into *RecordIO* format using the ``im2rec.py`` utility script that is provided in the MXNet [src/tools](https://github.com/dmlc/mxnet/tree/master/tools) folder.
 An example of how to use the script for converting to *RecordIO* format is shown in the `Image IO` section below.
 
+* Note that there is a C++ version of [im2rec](https://github.com/dmlc/mxnet/blob/master/tools/im2rec.cc), please refer to [here](https://mxnet.incubator.apache.org/faq/recordio.html) for more information.
+
 ## Image IO
 
 In this section, we will learn how to preprocess and load image data in MXNet.