[FFmpeg-devel] 回复： [PATCH] avcodec/videotoolboxenc: add low-latency encoding

[徐福隆]

Thank you for your review, and point out the details.
Actually, I have also considered this issue.
I see that some keys are used directly, some are used by compatibility.
I will use compat_key instead, and submit a new patch.


------------------ 原始邮件 ------------------
发件人:                                                                                                                        ""zhilizhao(赵志立)""                                                                                    <quinkblack at foxmail.com>;
发送时间: 2023年5月19日(星期五) 中午11:34
收件人: "FFmpeg development discussions and patches"<ffmpeg-devel at ffmpeg.org>;
抄送: "徐福隆"<839789740 at qq.com>;
主题: Re: [FFmpeg-devel] [PATCH] avcodec/videotoolboxenc: add low-latency encoding





> On May 19, 2023, at 11:17, xufuji456 <839789740 at qq.com> wrote:
> 
> When using low-latency mode, it eliminates frame reordering
> and follows a one-in-one-out encoding mode
> 
> Signed-off-by: xufuji456 <839789740 at qq.com>
> ---
> libavcodec/videotoolboxenc.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
> 
> diff --git a/libavcodec/videotoolboxenc.c b/libavcodec/videotoolboxenc.c
> index c6f22723d6..ae1ef32b2d 100644
> --- a/libavcodec/videotoolboxenc.c
> +++ b/libavcodec/videotoolboxenc.c
> @@ -1441,6 +1441,17 @@ static int vtenc_create_encoder(AVCodecContext   *avctx,
>         }
>     }
> 
> +    // low-latency mode: eliminate frame reordering, follow a one-in-one-out encoding mode
> +    if ((avctx->flags & AV_CODEC_FLAG_LOW_DELAY) && avctx->codec_id == AV_CODEC_ID_H264) {
> +        status = VTSessionSetProperty(vtctx->session,
> +                                      kVTVideoEncoderSpecification_EnableLowLatencyRateControl,
> +                                      kCFBooleanTrue);

Please use compat_keys in case of kVTVideoEncoderSpecification_EnableLowLatencyRateControl
isn’t available.

> +
> +        if (status) {
> +            av_log(avctx, AV_LOG_ERROR, "Error setting low latency property: %d\n", status);
> +        }
> +    }
> +
>     status = VTCompressionSessionPrepareToEncodeFrames(vtctx->session);
>     if (status) {
>         av_log(avctx, AV_LOG_ERROR, "Error: cannot prepare encoder: %d\n", status);
> -- 
> 2.32.0 (Apple Git-132)
> 
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