<p dir="auto">For example, we have an input tensor shape (50,256,256,1), where 50 is the number of images (depth), height and width of each image is 256 and the number of channel is 1.<br>
Then what is the difference between the following two operations?</p>
<ol dir="auto">
<li>model = Conv3D(32, (3, 3, 3), strides = 1, padding = 'same', data_format = 'channels_first')</li>
<li>model = Conv3D(32, (3, 3, 3), strides = 1, padding = 'same', data_format = 'channels_last')</li>
</ol>
<p dir="auto">My doubt is, if we take channel_first. Then applying 3x3x3 convolution would extract temporal information or not? Whether it would behave like a 2D convolution? (if yes, then what is the use of the 3rd dimension in con3D).</p>
<p dir="auto">Also, what is the exact padding scheme used when we set padding='same'. Is it zero padding?, one padding?, or data duplication?</p>
<p dir="auto">We are trying to make all the files in the codebase have a line lenght below 85. This has been done to nearly all files. Just five are not done yet:</p>
<ul dir="auto">
<li>keras/backend/cntk_backend.py</li>
<li>keras/backend/common.py</li>
<li>keras/backend/tensorflow_backend.py</li>
<li>keras/backend/theano_backend.py</li>
<li>tests/keras/backend/backend_test.py</li>
</ul>
<p dir="auto">If you want to take up this issue, please make one Pull request per file (you don't have to do all five pull requests at once). And once the lines are shorter for one file, you can remove the corresponding exception in the <a href="https://github.com/keras-team/keras/blob/master/pytest.ini">https://github.com/keras-team/keras/blob/master/pytest.ini</a> to enable the tests.</p>