I use python3 and try to get images by .rec file.
I use ImageRecordIter. After 3000000 images I have got, I see OpenCV Error: Assertion failed .
Also I tried only go by iterator and do nothing, but saw the same error on same image.

Here is part of my code.

data_iter = mx.io.ImageRecordIter(
path_imgrec=data_path, # the target record file
data_shape=(3, 112, 112), # output data shape. An 227x227 region will be cropped from the original image.
batch_size=BATCH_SIZE # number of samples per batch

)

data_iter.reset()
for batch in data_iter:
for i in range(BATCH_SIZE):
img = Image.fromarray(batch.data[0][i].asnumpy().astype(np.uint8).transpose((1, 2, 0)))
img.save(path)

Full Error message.
[18:27:27] src/io/iter_image_recordio_2.cc:170: ImageRecordIOParser2: Data/faces_vgg_112x112/train.rec, use 1 threads for decoding..
OpenCV Error: Assertion failed (!buf.empty() && buf.isContinuous()) in imdecode_, file /home/travis/build/dmlc/mxnet-distro/deps/opencv-3.3.0/modules/imgcodecs/src/loadsave.cpp, line 637
terminate called after throwing an instance of 'cv::Exception'
what(): /home/travis/build/dmlc/mxnet-distro/deps/opencv-3.3.0/modules/imgcodecs/src/loadsave.cpp:637: error: (-215) !buf.empty() && buf.isContinuous() in function imdecode_