CS525 S2002 Midterm

Enter your answers on the web page and after completing your answers, push the submit button.  You have until 3/21/2002 11:59pm to finish the midterm.Treat these questions as mulitple-choice questions. You must choose either yes or no for each answer. There are two questions that require you to enter answers to the textareas.
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  1. Introduction to Video
    1. What is PAL?
    2. 1. a video signal standard used in Japan Yes No
      2. 6MHz is allocated per channel Yes No
      3. video and audio signals are sent at different frequencies Yes No
      4. Each field contains 525 scanning line Yes No
    3. Relationship among bandwidth, scaning lines, frame rates, horizontal blanking (retract) period, horizontal resolution.
    4. 1. If other parameters are fixed,  higher frame rate implies more video bandwidth needed  Yes No
      2. If other parameters are fixed,  more scanning lines implies higher frame rate Yes No
      3. If other parameters are fixed,  shorter horizontal blanking period implies higher frame rates Yes No
      4. If other parameters are fixed,  longer horizontal blanking period implies higher resolution. Yes No
    5. HDTV vs. 35mm film
    6. 1. HDTV has higher resolutions Yes No
      2. HDTV has higher aperture response on wider (thick) HDTV line patterns. Yes No
      3. TV has higher aperture response on narrower (thin) HDTV line patterns. Yes No
    7. The day  light consists of lights of many colors.  Yes No
    8. Satuation of color in a light source indciates how bright is its color? Yes No
    9. YIQ video signal
    10. 1. Human eye are less sensitive to the luminence than color satuation Yes No
      2. Human eye are more sensitive to Q signal than I signal. Yes No
      3. When digitized TV signal, it make sense to give more bits to Q signal than I signal.  Yes No
      4. These three signal components are mixed during TV broadcast transmission. Yes No
  2. JPEG
    1. Zig-Zag Sequence and Run length Coding.

    2.         1.What is the intermediate encoding sequence for the computed DCT coefficients with 64, followed by 48zeros, -100, and the rest are zeros?

              2.How many  bits will be used  to encode this intermediate encoding sequence?

              3.Consider that 8 bits are used to encode the value of each original 64 values. What is compression ratio achieved by the combination of DCT, runlength and VLI coding?
  3. MPEG
    1. MPEG encoded frames generate fix data bit rate.  Yes No
    2. Which of the following approaches can achieve  higher compression ratio?
        1. Increase the number of quantization steps in the encoding of I frames Yes No
        2. Increase the search area in reference frame for matching the macroblock Yes No
        3. Use longer video sequence with fewer reference frames Yes No
    3. Assume the macroblock at (128, 128) of f2 happens to match exactly with the macroblock at (100, 110) of f4. Further assume that the macroblocks are encoded with <macroblock type><motion vector>[<motion vector>]<prediction error matrix's encoded bit stream>. Here we have a backward prediction case. Use the fomula, in the MPEG paper. Here subscript 2 is for the reference frame and 1 is for the frame with macroblock to be matched. What are the motion vector values to be encoded?
    4. Follow the above assumptions, and assume the macro block size is 32x32 instead of 16x16, 3 bits are used to macroblock type, each value of the motion vector are encoded in 10 bits. Forward Predicted and Backward Predicted macroblocks only have one motion vector. Bi-directional or average predicted macroblocks have two motion vectors. Prediction error matrix are encoded using the same JPEG encoding process. Compared with using 8 bits to encode each of 32x32 elements in the macroblock, what is the compression ratio for this macroblock?.
  4. Using Multimedia in Web Page
    1. How big is a raw 2 minutes, stereo, audio file sampled with 44kHz and 8 bits per sample?
        1. 352000 bytes. Yes No
        2. 21120000 bytes. Yes No
        3. 2640000 bytes. Yes No
    2. How to reference video?
    3. 1. Use <A HREF="video.avi"> Yes No
      2. Use <Object data="video.avi"> Yes No
      3. The  <Object data="video.avi">displays the video image on the same web page. Yes No
      4. The <A HREF="video.avi"> embeds the video image on the same web page. Yes No
  5. MIDI.
    The following is a MIDI file similar to Ballade.mid.
    4d 54 68 64    4-character chunk ID: "MThd"
    00 00 00 06    length of the header: 6 bytes
    00 01          file format: format 1
    00 10          # of tracks: 16 tracks in this file
    00 c0      MSb=0, resolution per quarter note: 192 ticks per quarter note
    4d 54 72 6b    4-character chunk ID: "MTrk"
    00 00 00 7c    length of the track: 124 Bytes

    delta time track event   Intepretation
    ========= ===========    =====================================
    00 ff 7f 03 00 00 41     meta event, (?) 3 bytes
    00 ff 58 04 04 02 18 08  Time signature meta event, 4/4 meter?
    00 ff 51 03 0a 49 6d     Tempo meta event, 674157 microsec/quarternote
    00 ff 59 02 00 00        Key signature meta event, C major
    00 ff 01 2a 43 6f ...    Copyright meta event?

    4d 54 72 6b              4-character chunk ID: "MTrk"
    00 00 09 61              length of the chunk data: 2401 bytes

    delta track event   Interpretation
    ===== ===========   =====================================
    00    ff 21 01 01   meta event?
    00    ff 03 14 50 ... instrument name, 20 bytes, Piano Treble
    00    c1 02         Program change on channel 1, patch #2
    00    b1 07 61      Control change on channel 1, volume level 91
                             (loud, 80 normal)
    00    b1 0a 7f      continuous controller(MIDI knob), max. postion(127)
    00    91 37 7f      Note on channel 1,note=55(G,octave3), vel=127(loud)
    60    39 7f         note=57, vel=127(loud) after 96/192 quarternote
                          (A, octave3), running status without command
    60    3c 7f         note=60(C, octave4), vel=127 after eighth note
    5e    41 7f         note=65(F, octave4), vel=127 after 94/192 qnote
    8140  43 7f         note=67(G, octave4), vel=127 after 192/192 qnote
    10    81 41 40      Note off, note=65, vel=64(med.) after 16/192 qnote
    8130  91 41 7f      Note on, note=65, vel=127 after 176/192 quarternote
    06    81 3c 40      Note off, note=60, vel=64 after 6/192 quarternote
    0c    37 40         note=55, vel=64, after 12/192 quarternote
    4e    91 37 7f      Note on, note=55, vel=127, after 78/192 qnote

    1. How long is betweent the starting playtime of the first note (G Octave3) and second note (A Octave3) in terms of seconds?
    2. If the above MIDI code after 4e 91 37 7f is followed by 81 40 91 3e 40. Explain these five bytes using the format similar to the above interpretation.