[FFmpeg-user] -debug mb_type option

[Oussama Stiti]

Hi everybody,

I need some help to understand what ffmpeg is printing on my terminal, when
i use the "-debug mb_type" option.

It displays:
[libx264 @ 0xa66b020] frame=  61 QP=30.04 NAL=0 Slice:B Poc:120 I:0
P:269  SKIP:115  size=627 bytes
[libx264 @ 0xa66b020] frame=  62 QP=24.74 NAL=2 Slice:P Poc:126 I:3
P:347  SKIP:46   size=2527 bytes
[libx264 @ 0xa66b020] frame=  63 QP=30.01 NAL=0 Slice:B Poc:124 I:0
P:260  SKIP:126  size=637 bytes
[libx264 @ 0xa66b020] frame=  64 QP=25.15 NAL=2 Slice:P Poc:130 I:6
P:320  SKIP:70   size=2426 bytes
[libx264 @ 0xa66b020] frame=  65 QP=30.12 NAL=0 Slice:B Poc:128 I:1
P:252  SKIP:133  size=654 bytes
[libx264 @ 0xa66b020] frame=  66 QP=24.80 NAL=2 Slice:P Poc:134 I:11
P:329  SKIP:56   size=2842 bytes
[libx264 @ 0xa66b020] frame=  67 QP=29.87 NAL=0 Slice:B Poc:132 I:0
P:257  SKIP:123  size=764 bytes
[libx264 @ 0xa66b020] frame=  68 QP=25.18 NAL=2 Slice:P Poc:138 I:13
P:319  SKIP:64   size=2578 bytes
[libx264 @ 0xa66b020] frame=  69 QP=28.90 NAL=0 Slice:B Poc:136 I:0
P:262  SKIP:126  size=680 bytes
[libx264 @ 0xa66b020] frame=  70 QP=24.84 NAL=2 Slice:P Poc:142 I:31
P:280  SKIP:85   size=2589 bytes
[libx264 @ 0xa66b020] frame=  71 QP=29.16 NAL=0 Slice:B Poc:140 I:0
P:221  SKIP:164  size=726 bytes
[libx264 @ 0xa66b020] frame=  72 QP=24.03 NAL=2 Slice:P Poc:146 I:30
P:333  SKIP:33   size=3018 bytes
[libx264 @ 0xa66b020] frame=  73 QP=29.36 NAL=0 Slice:B Poc:144 I:4
P:265  SKIP:114  size=810 bytes
[libx264 @ 0xa66b020] frame=  74 QP=24.59 NAL=2 Slice:P Poc:152 I:17
P:338  SKIP:41   size=2844 bytes
[libx264 @ 0xa66b020] frame=  75 QP=28.69 NAL=2 Slice:B Poc:150 I:0
P:266  SKIP:120  size=769 bytes
[libx264 @ 0xa66b020] frame=  76 QP=28.45 NAL=0 Slice:B Poc:148 I:1
P:252  SKIP:138  size=630 bytes
[libx264 @ 0xa66b020] frame=  77 QP=24.82 NAL=2 Slice:P Poc:156 I:29
P:300  SKIP:67   size=3043 bytes
[libx264 @ 0xa66b020] frame=  78 QP=28.92 NAL=0 Slice:B Poc:154 I:0
P:239  SKIP:136  size=775 bytes
[libx264 @ 0xa66b020] frame=  79 QP=24.48 NAL=2 Slice:P Poc:160 I:27
P:328  SKIP:41   size=3321 bytes
[libx264 @ 0xa66b020] frame=  80 QP=29.44 NAL=0 Slice:B Poc:158 I:1
P:246  SKIP:132  size=739 bytes
[libx264 @ 0xa66b020] frame=  81 QP=25.26 NAL=2 Slice:P Poc:164 I:37
P:263  SKIP:96   size=2700 bytes
[libx264 @ 0xa66b020] frame=  82 QP=30.06 NAL=0 Slice:B Poc:162 I:1
P:219  SKIP:161  size=700 bytes
[libx264 @ 0xa66b020] frame=  83 QP=25.18 NAL=2 Slice:P Poc:168 I:18
P:329  SKIP:49   size=3055 bytes
[libx264 @ 0xa66b020] frame=  84 QP=29.49 NAL=0 Slice:B Poc:166 I:1
P:225  SKIP:154  size=686 bytes
[libx264 @ 0xa66b020] frame=  85 QP=25.23 NAL=2 Slice:P Poc:172 I:20
P:313  SKIP:63   size=2951 bytes
[libx264 @ 0xa66b020] frame=  86 QP=30.00 NAL=0 Slice:B Poc:170 I:0
P:234  SKIP:141  size=716 bytes
[libx264 @ 0xa66b020] frame=  87 QP=25.63 NAL=2 Slice:P Poc:176 I:15
P:323  SKIP:58   size=2734 bytes


What is the interpretation of the value 0 or 2 for "NAL"? what "POC", "I",
"P" and "SKIP" refer to ?

*Cheers!
O. Stiti
*