[FFmpeg-devel] [PATCH] lavc/amfenc: Reference to input AVFrame (hwaccel) is retained during the encoding process

Mark Thompson sw at jkqxz.net
Sat Mar 24 16:38:40 EET 2018


On 23/03/18 11:19, Kravchenko, Alexander wrote:
> Re: [FFmpeg-devel] [PATCH] lavc/amfenc: Reference to input AVFrame (hwaccel) is retained during the encoding process

Say what the change is in the title.  Something like "amfenc: Retain a reference to D3D11 frames used as input during the encoding process", maybe?


> An additional reference to input AVFrame (hwaccel) is retained during the encoding process.
> This postpone reusing frames by decoder while they are used by encoder and prevents frame corruption
> Issue with frame corruption  was reproduced using:
> ffmpeg.exe -y -hwaccel d3d11va -hwaccel_output_format d3d11 -i input.h264  -an -c:v h264_amf output.mkv

How many frames can end up queued inside the encoder here?

> 
> From: Alexander Kravchenko <aakravchenko at luxoft.com>
> ---
>  libavcodec/amfenc.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 61 insertions(+), 3 deletions(-)
> 
> diff --git a/libavcodec/amfenc.c b/libavcodec/amfenc.c
> index 89a10ff253..9ffc52b0b0 100644
> --- a/libavcodec/amfenc.c
> +++ b/libavcodec/amfenc.c
> @@ -443,6 +443,41 @@ int ff_amf_encode_init(AVCodecContext *avctx)
>      return ret;
>  }
> 
> +#define AV_AMF_QUERY_INTERFACE(res, from, InterfaceType, to ) \
> +    { \
> +        AMFGuid guid_##InterfaceType = IID_##InterfaceType(); \
> +        res = from->pVtbl->QueryInterface(from, &guid_##InterfaceType, (void**)&to); \
> +    }
> +
> +#define AV_AMF_ASSIGN_PROPERTY_INTERFACE(res, pThis, name, val ) \
> +    { \
> +        AMFInterface *amf_interface; \
> +        AV_AMF_QUERY_INTERFACE(res, val, AMFInterface, amf_interface)\
> +        if(res == AMF_OK) { \

"if (", and in all places below too.

> +            AMFVariantStruct var; \
> +            AMFVariantInit(&var); \
> +            AMFVariantAssignInterface(&var, amf_interface); \
> +            amf_interface->pVtbl->Release(amf_interface); \
> +            res = pThis->pVtbl->SetProperty(pThis, name, var); \
> +            AMFVariantClear(&var); \

These AMFVariant functions all return an AMF_RESULT implying that they can fail (memory allocations?) - those should be checked.

> +        } \
> +    }
> +
> +#define AV_AMF_GET_PROPERTY_INTERFACE(res, pThis, name, target_type, val) \
> +    { \
> +        AMFVariantStruct var; \
> +        AMFVariantInit(&var); \
> +        res = pThis->pVtbl->GetProperty(pThis, name, &var); \
> +        if(res == AMF_OK) { \
> +            if(var.type == AMF_VARIANT_INTERFACE && var.pInterface) { \
> +                AMFGuid guid = IID_##target_type(); \
> +                res = var.pInterface->pVtbl->QueryInterface(var.pInterface, &guid, (void**)&val); \
> +            } else { \
> +                res = AMF_INVALID_DATA_TYPE; \
> +            } \
> +            AMFVariantClear(&var); \
> +        } \
> +    }

These should probably be functions rather than macros?  In any case, they shouldn't have the "AV_" prefix which is reserved for external symbols.

> 
>  int ff_amf_send_frame(AVCodecContext *avctx, const AVFrame *frame)
>  {
> @@ -484,6 +519,8 @@ int ff_amf_send_frame(AVCodecContext *avctx, const AVFrame *frame)
>              (ctx->hw_device_ctx && ((AVHWFramesContext*)frame->hw_frames_ctx->data)->device_ctx ==
>              (AVHWDeviceContext*)ctx->hw_device_ctx->data)
>          )) {
> +            AVFrame* frame_ref = av_frame_clone(frame);

av_frame_clone() can fail.

> +            AMFBuffer* frame_ref_storage_buffer;

Put the * in the right place - it's part of the declarator, not the declaration-specifiers.

>  #if CONFIG_D3D11VA
>              static const GUID AMFTextureArrayIndexGUID = { 0x28115527, 0xe7c3, 0x4b66, { 0x99, 0xd3, 0x4f, 0x2a, 0xe6, 0xb4, 0x7f, 0xaf } };
>              ID3D11Texture2D *texture = (ID3D11Texture2D*)frame->data[0]; // actual texture
> @@ -496,6 +533,12 @@ int ff_amf_send_frame(AVCodecContext *avctx, const AVFrame *frame)
>              // input HW surfaces can be vertically aligned by 16; tell AMF the real size
>              surface->pVtbl->SetCrop(surface, 0, 0, frame->width, frame->height);
>  #endif
> +            res = ctx->context->pVtbl->AllocBuffer(ctx->context, AMF_MEMORY_HOST, sizeof(frame_ref), &frame_ref_storage_buffer);
> +            AMF_RETURN_IF_FALSE(ctx, res == AMF_OK, AVERROR(ENOMEM), "AllocBuffer() failed  with error %d\n", res);
> +            memcpy(frame_ref_storage_buffer->pVtbl->GetNative(frame_ref_storage_buffer), &frame_ref, sizeof(frame_ref));
> +
> +            AV_AMF_ASSIGN_PROPERTY_INTERFACE(res, surface, L"av_frame_ref", frame_ref_storage_buffer);
> +            frame_ref_storage_buffer->pVtbl->Release(frame_ref_storage_buffer);

frame_ref is leaked if any of this buffer/property stuff fails.

>          } else {
>              res = ctx->context->pVtbl->AllocSurface(ctx->context, AMF_MEMORY_HOST, ctx->format, avctx->width, avctx->height, &surface);
>              AMF_RETURN_IF_FALSE(ctx, res == AMF_OK, AVERROR(ENOMEM), "AllocSurface() failed  with error %d\n", res);
> @@ -555,11 +598,26 @@ int ff_amf_receive_packet(AVCodecContext *avctx, AVPacket *avpkt)
>          if (data) {
>              // copy data to packet
>              AMFBuffer* buffer;
> -            AMFGuid guid = IID_AMFBuffer();
> -            data->pVtbl->QueryInterface(data, &guid, (void**)&buffer); // query for buffer interface
> +            AV_AMF_QUERY_INTERFACE(res, data, AMFBuffer, buffer);
> +            AMF_RETURN_IF_FALSE(ctx, res == AMF_OK, AVERROR_UNKNOWN, "Invalid data type from encoder->QueryOutput, should be AMFBuffer, error %d\n", res);
>              ret = amf_copy_buffer(avctx, avpkt, buffer);
> -
>              buffer->pVtbl->Release(buffer);
> +
> +            //try to get attached av_frame_ref and unref
> +            if(data->pVtbl->HasProperty(data, L"av_frame_ref")) {
> +                AMFBuffer *frame_ref_storage_buffer = NULL;
> +                AVFrame *av_frame_ref;
> +
> +                AV_AMF_GET_PROPERTY_INTERFACE(res, data, L"av_frame_ref", AMFBuffer, frame_ref_storage_buffer);
> +                if(res == AMF_OK) {
> +                    memcpy(&av_frame_ref, frame_ref_storage_buffer->pVtbl->GetNative(frame_ref_storage_buffer), sizeof(av_frame_ref));
> +                    av_frame_unref(av_frame_ref);

Leaks the AVFrame structure itself - you want av_frame_free().

> +                    frame_ref_storage_buffer->pVtbl->Release(frame_ref_storage_buffer);
> +                } else {
> +                    av_log(avctx, AV_LOG_WARNING, "av_frame_ref data attached to frame is corrupted\n");
> +                }
> +            }

Is there always an exact 1->1 correspondence between input frames and output packets?  That is, is it guaranteed that no frames are ever dropped, even in the low-latency modes?

> +
>              data->pVtbl->Release(data);
> 
>              AMF_RETURN_IF_FALSE(ctx, ret >= 0, ret, "amf_copy_buffer() failed with error %d\n", ret);
> --
> 2.16.2.windows.1
> 
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Thanks,

- Mark


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