Friday, February 01, 2008

MPEG4's Maximum Frame Size

H.263 specifies maximum frame size by means of "BPPmaxKb" parameter.BPPmaxKb defines the maximum frame size in terms of 1024 bits units.The standard specifies table for BPPMaxKb, which is dependentresolution. For QCIF, value of BPPmaxKb is 64 units, which translatesinto 8 Kbytes.

Does any body know whether there is limitation for maximum H.263 framesize?
For mpeg4 simple profile QCIF the spec said:

ISO/IEC 14496-2:2003(E) \ Annex D: Video buffering verifier \ D.2 VideoRate Buffer Model Definition clause 10:

The number of bits used for coding any single VOP, di, shall not exceedk * 16384 bits, where k = 4 for QCIF and Sub-QCIF, k = 16 for CIF, k =32 for 4CIF, and k = 64 for 16CIF, unless a larger value of k isspecified in the profile and level definition.
For QCIF, k=4. So maximum encoded frame size should be 8k bytes.

No comments: