
< int av_hwframe_ctx_init(AVBufferRef *ref)
< {
<     AVHWFramesContext *ctx = (AVHWFramesContext*)ref->data;
---
> int av_hwframe_ctx_init(AVBufferRef *ref)
> {
>     if (!ref)
>         return AVERROR(EINVAL);
>     AVHWFramesContext *ctx = (AVHWFramesContext*)ref->data;
