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Annex 3 to Doc. AVC-206R
Annex 3 to Doc. AVC-206R

Possible techniques to implement each requirement

Note: Reference to the Singapore meeting document MPEG92/nn is indicated as
/nn/, but the reference list is not exhaustive.

1. BIT RATE <01>

  a) NTSC/PAL/SECAM level at 3-5 Mbit/s
  b) Close to CCIR 601 level at 8-10 Mbit/s

2. PICTURE QUALITY <01>

  a) High quality                                 - pre-processing
                                                  - temporal prediction
                                                  - motion estimation
                                                  - non transform coding
                                                  - rate control
                                                  - etc.

  b) Graceful degradation for critical scenes     - rate control mechanism

  c) Minimum coder-decoder combination should
     provide targeted performance <02>

3. PICTURE FORMAT (INPUT/OUTPUT)                  - support of a range of
                                                    formats, both interlaced
  a) CCIR601 4:2:2                                  and progressive
  b) CCIR601 4:4:4                                - format indication bit
  c) EDTV (16:9 aspect ratio)
  d) Progressive format (film source etc.)
  e) Square pixel

4. MULTIPLE SCREENS/MULTIPLE IMAGES               - the same technique to
   (e.g. picture out of picture <03>)               achieve scalability
                                                  - system's support for
                                                    higher multiplex (multiple
                                                    programs)

5. FLEXIBILITY IN BIT RATE

  a) CBR and VBR                                  - rate control mechanism
  b) Rate control for VBR under bit
     generation constriction <04>

6. BITSTREAM SCALABILITY <05>                     - subband splitting
                                                  - pyramidal scheme /18,19,49/
  a) Spatial resolution scalability               - hierarchical layers in the
  b) Temporal resolution scalability                DCT frequency domain
  c) Coding noise scalability                       /11,39,45/
  d) Complexity scalability                       - frequency scanning /28/

7. CODING/DECODING DELAY <06>                     - forward prediction /28/
                                                  - field based coding /46/
                                                  - use of INTRA slice instead
                                                    of I pictures

8. ERROR PROTECTION FOR STORAGE AND TRANSPORT
   METHODS <07>

  a) Bit error resilience (random and burst)      - video multiplex structure
  b) Cell/packet loss resilience                    such as slice design and
                                                    absolute MB address
                                                  - leaky prediction /46/
                                                  - demand refresh
                                                  - error concealment
                                                  - packetization
                                                  - layered coding
                                                  - use of FEC/CRC cells
                                                  - use of two CLP's /28/
                                                  See  /20/ for general info.
                                                  on cell loss resilience.

  c) Graceful degradation for severe cases        - layered coding

  d) Recovery of synchronization after an         - GOP start code
     arbitrary point <08>

9. REPETITION OF CODING AND DECODING              (no positive techniques
                                                                    identified)

10. COMPLEXITY FLEXIBILITY                        - necessary minimum
                                                    specifications in the
                                                    normative part of standard

  a) Flexibility to allow tradeoff between
     performance and complexity <09>
  b) Intraframe mode only codec

11. COMPATIBILITY

  a) forward compatibility with MPEG1/H.261       - layered coding /11,19/
  b) backward compatibility with MPEG1/H.261      - embedded /13,18,59/
  c) u/d compatibility with EDTV, HDTV, SDTV      - simulcast
     <10>                                         - syntactic extension /28,59/

  d) Provision for future extension               - "hooks" in the syntax
     (e.g. extension to larger formats as HDTV)

12. EDITING ENCODED BITSTREAMS                    (no positive techniques
                                                   except editing on a GOP
                                                   basis in the MPEG1 system)

  a) Partial decoding and recoding for            - GOP structure
     rescaling <11>

13. TRICK MODE

  a) Fast playback (forward, backward)            - regularly spaced I pictures
                                                  - use of scalable features

  b) Normal reverse playback
  c) Slow motion


14. RANDOM ACCESS / CHANNEL HOPPING               - regularly spaced I pictures

15. REAL TIME ASPECT RATIO CHANGES <12>           - indication bit

  a) Pan/scan
  b) Letter box changes



Notes

<01> The standard should be flexible enough to cover a range of picture quality
     corresponding to a range of bit rates.
<02> Clarification is needed in the light of note <01>.
<03> 16:9 picture can contain one full size 4:3 picture with three additional
     1/9 sized 4:3 pictures.
<04> In case of ATM network, this network constriction is called Usage
     Parameter Control.  In case of multichannel transmission in the CBR
     environment, each channel rate should be controlled so as to maintain the
     aggregate bit rate should be constant.
<05> A bitstream is scalable when some coded bits can be disregarded and a
     usable image still results.  Bitstream scalability facilitates decoding
     the images at different rates and resolution scales through the design of
     the bitstream or data representation itself.  Real time transcoding
     between different bit rates can be achieved with this bitstream
     scalability.  See also MPEG92/078.
<06> See MPEG92/010 (AVC-179) for definition.
<07> Error protection will also be supported at the system level.
<08> Recovery after the channel is lost for a while.
<09> There is an unanswered question whether the standard should guarantee
     performance in addition to bitstream interchangeability.
<10> Awaiting definition of EDTV, HDTV, SDTV
<11> Home video editing may require this functionality.  MPEG1 system
     capability of cut and paste in GOP unit is sufficient for this purpose?
<12> Indicating sender's desire concerning what part of the 16:9 picture be
     displayed on 4:3 monitors.

END