Arky
16th June 2002, 03:49
TactX recently posted this quote:
[Quoted from the Berkeley Multimedia Research Center MPEG FAQ
Non-linear macroblock quantization was introduced in MPEG-2 to increase the precision of quantization at high bit rates (hence, low quantiser_scale values), while increasing the dynamic range for low bit rate use where larger step size is needed. The quantization_scale_code is switchable between the linear (MPEG-1 style) or non-linear scale on a picture coding (frame or field) basis. This new MPEG-2 non-linear scale corresponds to a dynamic range of 0.5 to 54 with respect to the old linear (MPEG-1 style) range of 1 to 31.
In other words: for MPEG-2 use non-linear.]
...and I myself posted this excerpt, from the Spruce MPX3000 manual:
["There are two types of quantization available in MPEG-2 video encoding: linear and non-linear (which is the default). MPEG-1 useslinear quantization only. MPEG-2 has both types of quantization available - though non-linear is used almost exclusively, as it provides greater dynamic range.
Note: When MPEG-2 was defined, the non-linear quantization scale was introduced as an across-the-board improvement on the previously used linear scale. The option of linear scale in MPEG-2 was defined only to accommodate full backward compatibility with MPEG-1. **There are no conditions known under which a linear quantization type would be preferable to Non-Linear type in MPEG-2"
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I do not offer this contribution as a criticism of Robshot et al's method - quite to the contrary, I congratulate them on a job well-done - a decent guide to cinemacraft, for us enthusiasts, has been needed for a long time and i was thrilled to see the excellent Robshot et al guide. It is the very nature of our little community that we advance our hobby through discussion and experimentation, and it is from this standpoint that I would be eager to see the Robshot et al Cinemacraft method/guide developed/honed further. Make of it what you will. ]
SO.... I am wondering if the last few months have brought us any closer to a method encompassing the thorny issue of variable quantisation. It seems a great pity not to capitalise upon an area of the MPEG2 spec which was clearly devised for a good reason, and which CCESP supports.
Comments please!
Arky ;o)
[Quoted from the Berkeley Multimedia Research Center MPEG FAQ
Non-linear macroblock quantization was introduced in MPEG-2 to increase the precision of quantization at high bit rates (hence, low quantiser_scale values), while increasing the dynamic range for low bit rate use where larger step size is needed. The quantization_scale_code is switchable between the linear (MPEG-1 style) or non-linear scale on a picture coding (frame or field) basis. This new MPEG-2 non-linear scale corresponds to a dynamic range of 0.5 to 54 with respect to the old linear (MPEG-1 style) range of 1 to 31.
In other words: for MPEG-2 use non-linear.]
...and I myself posted this excerpt, from the Spruce MPX3000 manual:
["There are two types of quantization available in MPEG-2 video encoding: linear and non-linear (which is the default). MPEG-1 useslinear quantization only. MPEG-2 has both types of quantization available - though non-linear is used almost exclusively, as it provides greater dynamic range.
Note: When MPEG-2 was defined, the non-linear quantization scale was introduced as an across-the-board improvement on the previously used linear scale. The option of linear scale in MPEG-2 was defined only to accommodate full backward compatibility with MPEG-1. **There are no conditions known under which a linear quantization type would be preferable to Non-Linear type in MPEG-2"
**********************************************************************
I do not offer this contribution as a criticism of Robshot et al's method - quite to the contrary, I congratulate them on a job well-done - a decent guide to cinemacraft, for us enthusiasts, has been needed for a long time and i was thrilled to see the excellent Robshot et al guide. It is the very nature of our little community that we advance our hobby through discussion and experimentation, and it is from this standpoint that I would be eager to see the Robshot et al Cinemacraft method/guide developed/honed further. Make of it what you will. ]
SO.... I am wondering if the last few months have brought us any closer to a method encompassing the thorny issue of variable quantisation. It seems a great pity not to capitalise upon an area of the MPEG2 spec which was clearly devised for a good reason, and which CCESP supports.
Comments please!
Arky ;o)