On 3/31/2020 12:31 PM, 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)
>
> Signed-off-by: Linjie Fu <linjie...@intel.com>
> ---
> [1]
> <https://github.com/cisco/openh264/blob/master/codec/encoder/core/src/encoder_ext.cpp#L375>
> [2] <https://github.com/cisco/openh264/issues/3259>
>
> libavcodec/libopenh264enc.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/libavcodec/libopenh264enc.c b/libavcodec/libopenh264enc.c
> index ae6d17c..7cd1efe 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, avctx->qmax) : 1;
Should be param.iMaxQp. avctx->qmax may be <= 0.
> param.iTemporalLayerNum = 1;
> param.iSpatialLayerNum = 1;
> param.bEnableDenoise = 0;
> @@ -332,6 +335,12 @@ static int svc_encode_frame(AVCodecContext *avctx,
> AVPacket *avpkt,
> return 0;
> }
>
> +static const AVCodecDefault svc_enc_defaults[] = {
> + { "qmin", "-1" },
> + { "qmax", "-1" },
> + { NULL },
> +};
> +
> AVCodec ff_libopenh264_encoder = {
> .name = "libopenh264",
> .long_name = NULL_IF_CONFIG_SMALL("OpenH264 H.264 / AVC / MPEG-4
> AVC / MPEG-4 part 10"),
> @@ -345,6 +354,7 @@ AVCodec ff_libopenh264_encoder = {
> .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
> FF_CODEC_CAP_INIT_CLEANUP,
> .pix_fmts = (const enum AVPixelFormat[]){ AV_PIX_FMT_YUV420P,
> AV_PIX_FMT_NONE },
> + .defaults = svc_enc_defaults,
> .priv_class = &class,
> .wrapper_name = "libopenh264",
> };
>
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