
< int av_hwframe_ctx_init(AVBufferRef *ref)
< {
<     AVHWFramesContext *ctx = (AVHWFramesContext*)ref->data;
<     const enum AVPixelFormat *pix_fmt;
<     int ret;
---
> int av_hwframe_ctx_init(AVBufferRef *ref)
> {
>     if (!ref || !ref->data)
>         return AVERROR(EINVAL);
>     AVHWFramesContext *ctx = (AVHWFramesContext*)ref->data;
>     if (!ctx->internal || !ctx->internal->hw_type)
>         return AVERROR(EINVAL);
>     const enum AVPixelFormat *pix_fmt;
>     int ret;
