On Wed, 15 Apr 2020, Linjie Fu wrote:
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] <https://github.com/cisco/openh264/issues/3259>
Signed-off-by: Linjie Fu <linjie...@intel.com>
---
libavcodec/libopenh264enc.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/libavcodec/libopenh264enc.c b/libavcodec/libopenh264enc.c
index dd5d4ee..c7ae5b1 100644
--- a/libavcodec/libopenh264enc.c
+++ b/libavcodec/libopenh264enc.c
@@ -135,6 +135,9 @@ FF_ENABLE_DEPRECATION_WARNINGS
param.iTargetBitrate = avctx->bit_rate;
param.iMaxBitrate = FFMAX(avctx->rc_max_rate,
avctx->bit_rate);
param.iRCMode = RC_QUALITY_MODE;
+ // QP = 0 is not well supported, so default to (1, 51)
+ param.iMaxQp = avctx->qmax >= 0 ? av_clip(avctx->qmax,
1, 51) : 51;
+ param.iMinQp = avctx->qmin >= 0 ? av_clip(avctx->qmin,
1, param.iMaxQp) : 1;
If qmax/qmin < 0, i.e. wasn't specified by the user, wouldn't it be better
to not touch param.iMax/MinQp at all (and use the default value of the
library, which may change between versions), instead of overriding it with
a value hardcoded here?
// Martin
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
