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

[Rick Kern]

On Fri, May 19, 2023 at 1:56 AM 徐福隆 <839789...@qq.com> wrote:

> 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.
>

The compat_keys are used for symbols that might not exist. For constants
available in the earliest version of VideoToolbox, compat_keys doesn't need
to be used.

Your patch looks good - I'll push it shortly.


> I will use compat_key instead, and submit a new patch.
>
>
> ------------------&nbsp;原始邮件&nbsp;------------------
> 发件人:
>                                                   ""zhilizhao(赵志立)""
>
> <quinkbl...@foxmail.com&gt;;
> 发送时间:&nbsp;2023年5月19日(星期五) 中午11:34
> 收件人:&nbsp;"FFmpeg development discussions and patches"<
> ffmpeg-devel@ffmpeg.org&gt;;
> 抄送:&nbsp;"徐福隆"<839789...@qq.com&gt;;
> 主题:&nbsp;Re: [FFmpeg-devel] [PATCH] avcodec/videotoolboxenc: add
> low-latency encoding
>
>
>
>
>
> &gt; On May 19, 2023, at 11:17, xufuji456 <839789...@qq.com&gt; wrote:
> &gt;
> &gt; When using low-latency mode, it eliminates frame reordering
> &gt; and follows a one-in-one-out encoding mode
> &gt;
> &gt; Signed-off-by: xufuji456 <839789...@qq.com&gt;
> &gt; ---
> &gt; libavcodec/videotoolboxenc.c | 11 +++++++++++
> &gt; 1 file changed, 11 insertions(+)
> &gt;
> &gt; diff --git a/libavcodec/videotoolboxenc.c
> b/libavcodec/videotoolboxenc.c
> &gt; index c6f22723d6..ae1ef32b2d 100644
> &gt; --- a/libavcodec/videotoolboxenc.c
> &gt; +++ b/libavcodec/videotoolboxenc.c
> &gt; @@ -1441,6 +1441,17 @@ static int
> vtenc_create_encoder(AVCodecContext&nbsp;&nbsp; *avctx,
> &gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }
> &gt;&nbsp;&nbsp;&nbsp;&nbsp; }
> &gt;
> &gt; +&nbsp;&nbsp;&nbsp; // low-latency mode: eliminate frame reordering,
> follow a one-in-one-out encoding mode
> &gt; +&nbsp;&nbsp;&nbsp; if ((avctx-&gt;flags &amp;
> AV_CODEC_FLAG_LOW_DELAY) &amp;&amp; avctx-&gt;codec_id == AV_CODEC_ID_H264)
> {
> &gt; +&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; status =
> VTSessionSetProperty(vtctx-&gt;session,
> &gt;
> +&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
> kVTVideoEncoderSpecification_EnableLowLatencyRateControl,
> &gt;
> +&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
> kCFBooleanTrue);
>
> Please use compat_keys in case of
> kVTVideoEncoderSpecification_EnableLowLatencyRateControl
> isn’t available.
>
> &gt; +
> &gt; +&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if (status) {
> &gt; +&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
> av_log(avctx, AV_LOG_ERROR, "Error setting low latency property: %d\n",
> status);
> &gt; +&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }
> &gt; +&nbsp;&nbsp;&nbsp; }
> &gt; +
> &gt;&nbsp;&nbsp;&nbsp;&nbsp; status =
> VTCompressionSessionPrepareToEncodeFrames(vtctx-&gt;session);
> &gt;&nbsp;&nbsp;&nbsp;&nbsp; if (status) {
> &gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; av_log(avctx,
> AV_LOG_ERROR, "Error: cannot prepare encoder: %d\n", status);
> &gt; --
> &gt; 2.32.0 (Apple Git-132)
> &gt;
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