> On Sep 1, 2023, at 12:07 AM, myp...@gmail.com wrote: > > On Fri, Sep 1, 2023 at 11:50 AM "zhilizhao(赵志立)" <quinkbl...@foxmail.com> > wrote: >> >> >> >>>> On Sep 1, 2023, at 09:13, myp...@gmail.com wrote: >>> >>> On Fri, Sep 1, 2023 at 2:13 AM Zhao Zhili <quinkbl...@foxmail.com> wrote: >>>> >>>> >>>>> From: ffmpeg-devel <ffmpeg-devel-boun...@ffmpeg.org> On Behalf Of Jun Zhao >>>>> Sent: 2023年8月31日 22:50 >>>>> To: ffmpeg-devel@ffmpeg.org >>>>> Cc: Jun Zhao <barryjz...@tencent.com>; Jun Zhao <mypopy...@gmail.com> >>>>> Subject: [FFmpeg-devel] [PATCH 2/2] lavc/videotoolboxenc: enable >>>>> low-latency mode for HEVC >>>>> >>>>> Enable the HEVC encoder that supports low-latency mode. >>>>> >>>>> Signed-off-by: Jun Zhao <barryjz...@tencent.com> >>>>> --- >>>>> libavcodec/videotoolboxenc.c | 3 ++- >>>>> 1 file changed, 2 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/libavcodec/videotoolboxenc.c b/libavcodec/videotoolboxenc.c >>>>> index 8e493c4f7a..bfc03787a0 100644 >>>>> --- a/libavcodec/videotoolboxenc.c >>>>> +++ b/libavcodec/videotoolboxenc.c >>>>> @@ -1568,7 +1568,8 @@ static int vtenc_configure_encoder(AVCodecContext >>>>> *avctx) >>>>> #endif >>>>> >>>>> // 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) { >>>>> + if ((avctx->flags & AV_CODEC_FLAG_LOW_DELAY) && >>>>> + (avctx->codec_id == AV_CODEC_ID_H264 || avctx->codec_id == >>>>> AV_CODEC_ID_HEVC)) { >>>> >>>> How about just remove the codec_id check? >>>> Is there any unwelcome side effects for encoders other than H264/HEVC? >>> >>> 1. One reason is that there are now other encoders available, such as >>> prores_videotoolbox. >>> >>> 2. It may be more appropriate to use a strictly qualified check >>> instead of an open condition. >> >> Both HEVC and ProRes failed with low_latency on my machine (with or without >> -allow_sw 1) >> >> [hevc_videotoolbox @ 0x61900002a380] Error: cannot create compression >> session: -12902 >> [prores_videotoolbox @ 0x61900002a380] Error: cannot create compression >> session: -12902 >> >> kVTParameterErr = >> -12902, >> > I think you missed the other options, low delay in VT encoder need to > co-work with some other options > >> 1. FFmpeg users should have an idea whether or not to set >> AV_CODEC_FLAG_LOW_DELAY. >> AV_CODEC_FLAG_LOW_DELAY doesn’t make sense for ProRes, but if user wants to >> try, let he/she >> do. >> >> 2. I can’t find API to query the capability. Only VideoToolBox framework >> itself know how >> to handle the argument. There isn’t much protect to provide for users. >> > Yes, now FFmpeg VT encoder didn't used the capability query, I think > need to used the some API VTCopySupportedPropertyDictionaryForEncoder > for capability query, this my next step That’s a good idea. We don’t have to worry about codec checks or unexpected failures if the HEVC encoder on some devices doesn’t support it. Ideally we can print out a warn message and ignore the low-delay flag.
>> Even with H.264, the results is unexpected: the input framerate is 25 but >> the output >> framerate is 5, it dropped 80 percent frames silently. >> > _______________________________________________ > 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". _______________________________________________ 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".