106 Can MPEG be used to code still frames ? (MPEG-2)
Description
This article is from the MPEG FAQ, by Frank Gadegast phade@cs.tu-berlin.de with numerous contributions by others.
106 Can MPEG be used to code still frames ? (MPEG-2)
Yes. MPEG Intra pictures are similar to baseline sequential JPEG pictures.
There are, of course, advantages and disadvantages to using MPEG over
JPEG to represent still pictures.
Disadvantages:
1. MPEG has only one color space (YCbCr)
2. MPEG-1 and MPEG-2 Main Profile luma and chroma share quanitzation
and VLC tables (4:2:0 chroma_format)
3. MPEG-1 is syntactically limited to 4k x 4k images, and 16k x 16k for MPEG-2.
Advantages:
1. MPEG possesses adaptive quantization which permits better rate
control and spatial masking.
2. With its limited still image syntax, MPEG averts any temptation to
use unnecessary, expensive, and academic encoding methods that have
little impact on the overall picture quality (you know who you are).
3. Philips' CD-I spec. has a requirement for a MPEG still frame mode,
with double SIF image resolution. This is technically feasible mostly
thanks to the fact that only one picture buffer is needed to decode a
still image instead of the 2.5 to 3 buffers needed for IPB sequences.
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