Organizational Questions:
[WiSe2021/22]
- Can you please shift the exam from 12am to 3pm as most of the students have Software Service Engineering on the same day which will start at 9am and end at 10:30am?
- Please next time, contact me earlier in this regard (ideally when the exam dates are first announced). The exam planning is a complex taks with many students from different courses. Conflicts must be early indicated to me (Danny Kowerko or René Erler). Early means many weeks before the real exam to see whether the exam organisation can manage to switch.
- In general exam collisions are not per se avoided between 1st or 3rd semester students. E.g. if a lecture is regularely planned for 3rd semester students and you are 1st semester, you can have collisions of your 1st semester exams with those of 3rd semester (students) exams.
- When will we receive the Maxexam link of the exam?
- It will be linked to the Exam FAQ in Opal and additionally you will get an email via Opal.
[Last semesters]
Q: Is there multiple choice questions for the exam?
A: We are still finalizing the exam. So there maybe be some in it, but if so at all, very very few of them only.
Q: Will the exam pattern be the same as in the mock test? Typing long answers in the box will take time. Will 1 hour be sufficient?
A: The mock exam is the exam from summer semester 2019: https://bildungsportal.sachsen.de/opal/auth/RepositoryEntry/3190226946/CourseNode/100097323611697 The real exam will be very similar to the mock exam. We are aware of the time requirements and we will make it achievable to solve it in 60 min.
Q: Should we expect a task (like the one in the mock exam) where we have to "draw" a tree with a text editor?
A: No, you don't have to draw anything, neither in a text editor nor on paper. You don't have to upload any drawn images. Everything will be solvable in the text entry fields as conveniently as possible. We updated the style of the "tree"-tasks, so that the formatting of the tasks will allow you to give the solutions conveniently.
Q: Is a calculator allowed or not?
A: No additional tools are allowed (calculator, smartphone, smartwatch, etc.)
Q: What will be the webcam setup for the exam? Do we need two webcams?
A: On the startpage of the course in the exam environment you will find an image which shows the webcam setup. You don’t need two webcams. Your smartphone is used as your only webcam and needs to be places so that we can see part of your screen and if possible the door behind you.
Q: Instead of the smartphone is another laptop okay? Because while sharing the camera from the phone I was facing some problems (it was showing sharing but never shared after).
A: No, using a second laptop as a camera is not allowed.
Q: What happens if for some reason (no battery left or something like that) the camera turns off?
A: We will ask you to try your best to get it up and running again. We are aware that technical equipment can fail, so we will be somewhat relaxed when it comes to those issues and not immediately exclude you from the exam.
Q: I have problems accessing the lecture content in Opal, what can I do?
A: Please make sure you are enrolled in any of the following learning groups: MC WiSe 2021/22 - Exam If you are enrolled in one of those and still have troubles accessing the material, please write us an email.
Q. The exam last semester was pretty lengthy. Can you please maybe this time make it so that we can be able to complete it easily in the time frame? because it takes time from our side to fill the run lenght encoding and huffman encoding tree on the exam portal.
Subject-related Questions:
- In MPEG type encoding, how can we identify the sequence of transmission order? That is, after how many B frames does a P frame or an I frame come?
- Unit_08_VideoEncoding_Slides.pdf slide 12: this the standard order and number of B frames.
- Can you explain the mpeg frame transmission order?
- The encoder encodes the images in a different order than the visual appearance. The B frame calculation requires two input signals, the I and P frame. So to calculate B frames the encoder needs to provide the I and P frame before the B frames.
Now, on the recieving end (consider this as a live stream) we first receive an I frame, which we can show on screen directly no problem, since it's a full (basically JPEG) image. Next we want to show the B frame on screen. But in order to do that we need the P frame first, since the B frame that we want to show relies on the I and P frames (the arrows in the figure on slide 12 of Unit_08_VideoEncoding_Slides.pdf show how the frames depend on one another). That's why we need to transmit in the order: I frame, then P frame, then B frame etc. So for that reason the frame transmission order differs from the visual appearance order.
- How to solve the graph questions online like the questions given in Tutorial 2:
- This is done by "graphical tasks", where you have to click and mark the right spot in a given graph image in order to indicate eg. that you understood the concept of sampling.
- In Shannon Fano/Huffman Encoding, will the answer be right if the code at the end is right, but the tree is wrong or incomplete?
- We cannot grant full points in this case. The tree will be graded as well as the resulting encoded message. We will, however, check trees manually to make sure you get the most points possible. In case you are still unhappy with the grading you can always apply for an exam review.
- In JPEG encoding, when we do chroma subsampling, is 4:4:4 considered as a subsampling or does only something like 4:2:0 count as subsampling?
- 4:4:4 -> for going with the lossless encoding in order to not loose the color information. Be aware that losslessness then also requires no information loss due to quantization, ie. quantization tables should consist of ones only, too. Basically, 4:4:4 is a color conversion only, but not real subsampling. The forth and back conversion between YCbCr and RGB ist probably not 100% lossless reversible, but potentially >99% where its regarded as lossless. You might try some examples with the equations for color conversion and see if after rounding to uint8 the values are preserved. ;-)
- 4:2:0 -> this is where subsampling really happens. So the term subsampling really applies here.