[encoder_ext]set iMinQp to 0 would lead to unexpected QP changing #3259
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Yes. Although QP=0 is allowed in Rec, it is not well supported here. You may first try to not use QP=0. |
fulinjie
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Mar 31, 2020
Set default QP range to (1, 51) instead of (2, 32). If iMaxQp/iMinQp equals 0, the QP range would be changed unexpectedly inside libopenh264 with a warning: Warning:Change QP Range from(0,51) to (12,42) And QP = 0 is not well supported currently. [1] <https://github.com/cisco/openh264/blob/master/codec/encoder/core/src/encoder_ext.cpp#L375> [2] <cisco/openh264#3259> Signed-off-by: Linjie Fu <linjie.fu@intel.com>
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hi @huili2 , thanks for the information. I'd like to reduce the qp range to (1, 51): |
fulinjie
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Apr 3, 2020
Set default QP range to (1, 51) instead of (2, 32). QP = 0 is not well supported currently in libopenh264. If iMaxQp/iMinQp equals 0, the QP range would be changed unexpectedly inside libopenh264 with a warning: Warning:Change QP Range from(0,51) to (12,42) [1] <https://github.com/cisco/openh264/blob/master/codec/encoder/core/src/encoder_ext.cpp#L375> [2] <cisco/openh264#3259> Signed-off-by: Linjie Fu <linjie.fu@intel.com>
fulinjie
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Apr 11, 2020
Set default QP range to (1, 51) instead of (2, 32). QP = 0 is not well supported currently in libopenh264. If iMaxQp/iMinQp equals 0, the QP range would be changed unexpectedly inside libopenh264 with a warning: Warning:Change QP Range from(0,51) to (12,42) [1] <https://github.com/cisco/openh264/blob/master/codec/encoder/core/src/encoder_ext.cpp#L375> [2] <cisco/openh264#3259> Signed-off-by: Linjie Fu <linjie.fu@intel.com>
fulinjie
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Apr 28, 2020
Clip iMinQp/iMaxQp to (1, 51) if user specified qp range explicitly since QP = 0 is not well supported currently in libopenh264, otherwise leave iMinQp/iMaxQp untouched and use the values initialized in FillDefault(). Note that if iMaxQp/iMinQp equals 0, the QP range would be adjusted inside libopenh264 with a warning: Warning:Change QP Range from(0,51) to (12,42) <https://github.com/cisco/openh264/blob/master/codec/encoder/core/src/encoder_ext.cpp#L375> <cisco/openh264#3259> Signed-off-by: Linjie Fu <linjie.fu@intel.com>
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Filed a PR to change the the verbosity level in case we ran into this warning all the time for qp = 0: |
fulinjie
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Apr 28, 2020
Clip iMinQp/iMaxQp to (1, 51) if user specified a non-zero qp range explicitly. If setting iMinQp/iMaxQp to 0, the QP range would be adjusted to use the defaults inside libopenh264 library according to the usage type. If not set, leave iMinQp/iMaxQp untouched and use the values initialized in FillDefault(). <https://github.com/cisco/openh264/blob/master/codec/encoder/core/src/encoder_ext.cpp#L375> <cisco/openh264#3259> Signed-off-by: Linjie Fu <linjie.fu@intel.com>
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While doing some integrations in FFmpeg, found that if either qmax or qmin is set to 0, unexpected QP changing would be observed.
Log:
Warning:Change QP Range from(0,51) to (12,42)
if ((pCfg->iMaxQp <= 0) || (pCfg->iMinQp <= 0))
https://github.com/cisco/openh264/blob/master/codec/encoder/core/src/encoder_ext.cpp#L375
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