On Tue, Aug 6, 2019 at 10:55 AM Fu, Linjie <linjie...@intel.com> wrote: > > > -----Original Message----- > > From: ffmpeg-devel [mailto:ffmpeg-devel-boun...@ffmpeg.org] On Behalf > > Of Hendrik Leppkes > > Sent: Tuesday, August 6, 2019 16:27 > > To: FFmpeg development discussions and patches <ffmpeg- > > de...@ffmpeg.org> > > Subject: Re: [FFmpeg-devel] [PATCH, v2 2/2] lavc/vaapi_decode: recreate > > hw_frames_ctx for vp9 without destroy va_context > > > > On Thu, Jul 11, 2019 at 10:20 AM Linjie Fu <linjie...@intel.com> wrote: > > > > > > VP9 allows resolution changes per frame. Currently in VAAPI, resolution > > > changes leads to va context destroy and reinit. This will cause > > > reference frame surface lost and produce garbage. > > > > > > Though refs surface id could be passed to media driver and found in > > > RTtbl, vp9RefList[] in hal layer has already been destroyed. Thus the > > > new created VaContext could only got an empty RefList. > > > > > > As libva allows re-create surface separately without changing the > > > context, this issue could be handled by only recreating hw_frames_ctx. > > > > > > Set hwaccel_priv_data_keeping flag for vp9 to only recreating > > > hw_frame_ctx when dynamic resolution changing happens. > > > > > > Could be verified by: > > > ffmpeg -hwaccel vaapi -hwaccel_device /dev/dri/renderD128 -i > > > ./resolutions.ivf -pix_fmt p010le -f rawvideo -vframes 20 -y vaapi.yuv > > > > > > Signed-off-by: Linjie Fu <linjie...@intel.com> > > > --- > > > libavcodec/decode.c | 10 +++++----- > > > libavcodec/internal.h | 1 + > > > libavcodec/pthread_frame.c | 2 ++ > > > libavcodec/vaapi_decode.c | 40 ++++++++++++++++++++++---------------- > > -- > > > libavcodec/vaapi_vp9.c | 4 ++++ > > > 5 files changed, 34 insertions(+), 23 deletions(-) > > > > > > diff --git a/libavcodec/decode.c b/libavcodec/decode.c > > > index 0863b82..7b15fa5 100644 > > > --- a/libavcodec/decode.c > > > +++ b/libavcodec/decode.c > > > @@ -1254,7 +1254,6 @@ int > > ff_decode_get_hw_frames_ctx(AVCodecContext *avctx, > > > > > > frames_ctx = (AVHWFramesContext*)avctx->hw_frames_ctx->data; > > > > > > - > > > if (frames_ctx->initial_pool_size) { > > > // We guarantee 4 base work surfaces. The function above > > > guarantees > > 1 > > > // (the absolute minimum), so add the missing count. > > > > Unrelated whitespace change > > There is a redundant whitespace here, so I removed it within this patch. > > > > @@ -1333,7 +1332,7 @@ static int hwaccel_init(AVCodecContext *avctx, > > > return AVERROR_PATCHWELCOME; > > > } > > > > > > - if (hwaccel->priv_data_size) { > > > + if (hwaccel->priv_data_size && !avctx->internal->hwaccel_priv_data) { > > > avctx->internal->hwaccel_priv_data = > > > av_mallocz(hwaccel->priv_data_size); > > > if (!avctx->internal->hwaccel_priv_data) > > > @@ -1396,9 +1395,10 @@ int ff_get_format(AVCodecContext *avctx, > > const enum AVPixelFormat *fmt) > > > memcpy(choices, fmt, (n + 1) * sizeof(*choices)); > > > > > > for (;;) { > > > - // Remove the previous hwaccel, if there was one. > > > - hwaccel_uninit(avctx); > > > - > > > + // Remove the previous hwaccel, if there was one, > > > + // and no need for keeping. > > > + if (!avctx->internal->hwaccel_priv_data_keeping) > > > + hwaccel_uninit(avctx); > > > user_choice = avctx->get_format(avctx, choices); > > > if (user_choice == AV_PIX_FMT_NONE) { > > > // Explicitly chose nothing, give up. > > > > There could be a dozen special cases how stuff can go wrong here. What > > if get_format actually returns a different format then the one > > currently in use? Or a software format? > > Just removing this alone is not safe. > > Didn't quite get your point. > IMHO, avctx->internal->hwaccel_priv_data_keeping won't be set in other cases > other than vaapi_vp9, so this patch won't break the default pipeline, and > hwaccel_uninit(avctx) will always be called. >
The point is that you cannot rely on get_format to return the same format that it previously did. It could return a software format, or in some cases possibly even a different hardware format. And you just don't handle that. The entire approach here smells a bit of hack. Lets try to think this through and do it properly. One idea that comes to mind is a new hwaccel callback that checks if a in-place re-init is possible without destroying everything. This could be used for a multitude of different situations, and not just this one special case. - Hendrik _______________________________________________ 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".