fix crash if change va to ff

src/QtAV/private/VideoDecoderFFmpegHW_p.h

@@ -33,10 +33,27 @@ public:
         : VideoDecoderFFmpegPrivate()
         , va_pixfmt(QTAV_PIX_FMT_C(NONE))
     {
+        get_format = 0;
+        get_buffer = 0;
+        release_buffer = 0;
+        reget_buffer = 0;
+        //get_buffer2 = 0;
         // subclass setup va_pixfmt here
     }
 
-    virtual ~VideoDecoderFFmpegHWPrivate() {}
+    virtual ~VideoDecoderFFmpegHWPrivate() {
+        restore();
+    }
+    void restore() {
+        codec_ctx->pix_fmt = pixfmt;
+        codec_ctx->opaque = 0;
+        codec_ctx->get_format = get_format;
+        codec_ctx->get_buffer = get_buffer;
+        codec_ctx->release_buffer = release_buffer;
+        codec_ctx->reget_buffer = reget_buffer;
+        //codec_ctx->get_buffer2 = get_buffer2;
+    }
+
     virtual bool setup(void **hwctx, AVPixelFormat *chroma, int w, int h) = 0;
 
     AVPixelFormat getFormat(struct AVCodecContext *p_context, const AVPixelFormat *pi_fmt);
@@ -44,6 +61,14 @@ public:
     virtual void releaseBuffer(void *opaque, uint8_t *data) = 0;
 
     AVPixelFormat va_pixfmt;
+    AVPixelFormat pixfmt; //store old one
+    //store old values because it does not own AVCodecContext
+    AVPixelFormat (*get_format)(struct AVCodecContext *s, const enum AVPixelFormat * fmt);
+    int (*get_buffer)(struct AVCodecContext *c, AVFrame *pic);
+    void (*release_buffer)(struct AVCodecContext *c, AVFrame *pic);
+    int (*reget_buffer)(struct AVCodecContext *c, AVFrame *pic);
+    //int (*get_buffer2)(struct AVCodecContext *s, AVFrame *frame, int flags);
+
     QString description;
 };
 

src/VideoDecoderDXVA.cpp

@@ -366,12 +366,13 @@ VideoDecoderDXVA::VideoDecoderDXVA()
 
 VideoDecoderDXVA::~VideoDecoderDXVA()
 {
-    setCodecContext(0);
 }
 
 VideoFrame VideoDecoderDXVA::frame()
 {
     DPTR_D(VideoDecoderDXVA);
+    if (!d.frame->opaque || !d.frame->data[0])
+        return VideoFrame();
     if (d.width <= 0 || d.height <= 0 || !d.codec_ctx)
         return VideoFrame();
     Q_ASSERT(d.output == MAKEFOURCC('Y','V','1','2'));

src/VideoDecoderFFmpegHW.cpp

@@ -121,7 +121,6 @@ AVPixelFormat VideoDecoderFFmpegHWPrivate::getFormat(struct AVCodecContext *p_co
 
     close();
     //vlc_va_Delete(p_va);
-
 end:
     qWarning("acceleration not available" );
     /* Fallback to default behaviour */
@@ -152,6 +151,14 @@ bool VideoDecoderFFmpegHW::prepare()
     }
 #endif
     d.codec_ctx->opaque = &d; //is it ok?
+
+    d.pixfmt = d.codec_ctx->pix_fmt;
+    //d.get_buffer2 = d.codec_ctx->get_buffer2;
+    d.get_buffer = d.codec_ctx->get_buffer;
+    d.reget_buffer = d.codec_ctx->reget_buffer;
+    d.release_buffer = d.codec_ctx->release_buffer;
+    d.get_format = d.codec_ctx->get_format;
+
     d.codec_ctx->get_format = ffmpeg_get_va_format;
 //#if LIBAVCODEC_VERSION_MAJOR >= 55
     //d.codec_ctx->get_buffer2 = ffmpeg_get_va_frame;
@@ -169,7 +176,7 @@ bool VideoDecoderFFmpegHW::decode(const QByteArray &encoded)
 {
     if (!isAvailable())
         return false;
-    DPTR_D(VideoDecoder);
+    DPTR_D(VideoDecoderFFmpegHW);
     AVPacket packet;
     av_new_packet(&packet, encoded.size());
     memcpy(packet.data, encoded.data(), encoded.size());
@@ -191,8 +198,10 @@ bool VideoDecoderFFmpegHW::decode(const QByteArray &encoded)
     // TODO: wait key frame?
     if (!d.codec_ctx->width || !d.codec_ctx->height)
         return false;
+    // avcodec_align_dimensions2
     d.width = d.codec_ctx->width;
     d.height = d.codec_ctx->height;
+    //avcodec_align_dimensions2(d.codec_ctx, &d.width_align, &d.height_align, aligns);
     return true;
 }
 

src/VideoDecoderVAAPI.cpp

@@ -154,12 +154,13 @@ VideoDecoderVAAPI::VideoDecoderVAAPI()
 
 VideoDecoderVAAPI::~VideoDecoderVAAPI()
 {
-    setCodecContext(0);
 }
 
 VideoFrame VideoDecoderVAAPI::frame()
 {
     DPTR_D(VideoDecoderVAAPI);
+    if (!d.frame->opaque || !d.frame->data[0])
+        return VideoFrame();
     VASurfaceID surface_id = (VASurfaceID)(uintptr_t)d.frame->data[3];
 #if VA_CHECK_VERSION(0,31,0)
     if (vaSyncSurface(d.display, surface_id))