The MPEG standard

What about MPEG-1 decoder chips ?

By implication of MPEG-2 Conformance requirements, all MPEG-2 decoders are required to decode MPEG-1 bitstreams as well. These chips, however, are strictly MPEG-1: 

  C-Cube CL-450           SIF rates. Single-chip.       Has on-board CPU.
  SGS-Thomson STi3400     SIF rates. Single-chip.       Hardwired.
  Motorola MCD250         SIF rates. Single-chip.  
  LSI 641172              CCIR-601 rates. Single-chip.  Systems packet 
                                                        decoder on-chip.

What about audio chips ?

Intermetall (ITT) produces the the MAS 3503 C single chip Layer 3 decoder.

Layer I and Layer II have been implemented in dedicated (ASIC) silicon by the following manufacturers : 

  Motorola MCD260
                
  Texas Instruments TI 320AV110 
        hardwired with systems parsing)                      
        operates in free format (arbitrary sample rate)
        120 pin PQFP package
        Serial data port
        Part of technology exchange with C-Cube

  LSI Logic L64111 
        hardwired w/CPU with on-chip systems parsing.
        Serial data port                        
        100-pin PQFP              
        
  GCA/ASCII ?
  
  Crystal Semiconductor CS4920
        on-chip, 2 channel 16-bit digital-to-analog converter (DAC)
        16 MIPS, 24-bit DSP 
        programmable clock manager
        44-pin PLCC package
        Programmable architecture.  For example, can download Layer II 
          MPEG-1 audio or Dolby AC-2
        $38 each in large quantities


  Dolby AC-3
        MPEG NY disclosure
        claimed to be less computationally intensive
        Zoran, GI working on own DSP-like dedicated chips.

Will there be an MPEG video tape format ?

There is a consortium of companies (Philips, JVC, Sony, Matushista, et al) developing a metal particle based 6 millimeter consumer digital video tape format. It will initially use more JPEG-like independent frame compression for cheap encoding of source analog (NTSC, PAL) video. The consequence of course is less efficient use of bandwidth ( 25 Mbit/sec for the same quality achieved at 6 Mbit/sec with MPEG). Pre-compressed video from broadcast sources will be directly recorded to tape and passed-through as a coded bitstream to the video decompression box upon playback.

Is so-and-so really MPEG compliant ?

At the very least, there are two areas of conformance/compliance in MPEG :

  1. Compliant bitstreams
  2. Compliant decoders
Technically speaking, video bitstreams consisting entirely of I-frames (such as those generated by Xing software) are syntactically compliant with the MPEG specification. The I-frame sequence is simply a subset of the full syntax. Compliant bitstreams must obey the range limits (e.g. motion vectors limited to +/-128, frame sizes, frame rates, etc.) and syntax rules (e.g. all slices must commence and terminate with a non-skipped macroblock, no gaps between slices, etc.). Some encoders also drop some frames, but this is not compliant.

Decoders, however, cannot escape true conformance. For example, decoders that cannot decode P or B frames are not legal MPEG. Likewise, full arithmetic precision must be obeyed before any decoder can be called MPEG compliant. The IDCT, inverse quantizer, and motion compensated prediction must meet the specification requirements which are fairly rigid (e.g. no more than 1 least significant bit of error between reference and test decoders). Real-time conformance is more complicated to measure than arithmetic precision, but it is reasonable to expect that decoders that skip frames on reasonable bitstreams are not likely to be considered compliant.