[FFmpeg-devel,v3,3/3] all: Link to "context" from all contexts with documentation

diff --git a/libavcodec/aacdec.h b/libavcodec/aacdec.h
index 1b245f9258..715886ae07 100644
--- a/libavcodec/aacdec.h
+++ b/libavcodec/aacdec.h
@@ -181,7 +181,7 @@  typedef struct DynamicRangeControl {
 } DynamicRangeControl;
 
 /**
- * main AAC decoding context
+ * main AAC decoding @ref md_doc_2context "context"
  */
 typedef struct AACDecContext {
     const struct AVClass  *class;
diff --git a/libavcodec/aacenc.h b/libavcodec/aacenc.h
index 8899f90ac7..755f0495a2 100644
--- a/libavcodec/aacenc.h
+++ b/libavcodec/aacenc.h
@@ -193,7 +193,7 @@  typedef struct AACPCEInfo {
 } AACPCEInfo;
 
 /**
- * AAC encoder context
+ * AAC encoder @ref md_doc_2context "context"
  */
 typedef struct AACEncContext {
     AVClass *av_class;
diff --git a/libavcodec/ac3enc.h b/libavcodec/ac3enc.h
index 30812617cc..c725007077 100644
--- a/libavcodec/ac3enc.h
+++ b/libavcodec/ac3enc.h
@@ -152,7 +152,7 @@  typedef struct AC3Block {
 } AC3Block;
 
 /**
- * AC-3 encoder private context.
+ * AC-3 encoder private @ref md_doc_2context "context"
  */
 typedef struct AC3EncodeContext {
     AVClass *av_class;                      ///< AVClass used for AVOption
diff --git a/libavcodec/amfenc.h b/libavcodec/amfenc.h
index 2dbd378ef8..f142ede63a 100644
--- a/libavcodec/amfenc.h
+++ b/libavcodec/amfenc.h
@@ -43,7 +43,7 @@  typedef struct AmfTraceWriter {
 } AmfTraceWriter;
 
 /**
-* AMF encoder context
+* AMF encoder @ref md_doc_2context "context"
 */
 
 typedef struct AmfContext {
diff --git a/libavcodec/atrac.h b/libavcodec/atrac.h
index 05208bbee6..1527e376a9 100644
--- a/libavcodec/atrac.h
+++ b/libavcodec/atrac.h
@@ -39,7 +39,7 @@  typedef struct AtracGainInfo {
 } AtracGainInfo;
 
 /**
- *  Gain compensation context structure.
+ *  Gain compensation @ref md_doc_2context "context"
  */
 typedef struct AtracGCContext {
     float   gain_tab1[16];  ///< gain compensation level table
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 968009a192..9180fedca7 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -430,7 +430,8 @@  typedef struct RcOverride{
 #define AV_GET_ENCODE_BUFFER_FLAG_REF (1 << 0)
 
 /**
- * main external API structure.
+ * @ref md_doc_2context "Context" for an encode or decode session
+ *
  * New fields can be added to the end with minor version bumps.
  * Removal, reordering and changes to existing fields require a major
  * version bump.
diff --git a/libavcodec/bsf.h b/libavcodec/bsf.h
index a09c69f242..bf79afa7cc 100644
--- a/libavcodec/bsf.h
+++ b/libavcodec/bsf.h
@@ -56,7 +56,7 @@ 
  */
 
 /**
- * The bitstream filter state.
+ * Bitstream filter @ref md_doc_2context "context"
  *
  * This struct must be allocated with av_bsf_alloc() and freed with
  * av_bsf_free().
diff --git a/libavcodec/d3d11va.h b/libavcodec/d3d11va.h
index 27f40e5519..ec0c472ab9 100644
--- a/libavcodec/d3d11va.h
+++ b/libavcodec/d3d11va.h
@@ -46,8 +46,7 @@ 
  */
 
 /**
- * This structure is used to provides the necessary configurations and data
- * to the Direct3D11 FFmpeg HWAccel implementation.
+ * @ref md_doc_2context "Context" for the Direct3D11 FFmpeg HWAccel implementation
  *
  * The application must make it available as AVCodecContext.hwaccel_context.
  *
diff --git a/libavcodec/mediacodec.h b/libavcodec/mediacodec.h
index 4e9b56a618..9967a7cfb3 100644
--- a/libavcodec/mediacodec.h
+++ b/libavcodec/mediacodec.h
@@ -26,7 +26,7 @@ 
 #include "libavcodec/avcodec.h"
 
 /**
- * This structure holds a reference to a android/view/Surface object that will
+ * @ref md_doc_2context "Context" for the android/view/Surface object that will
  * be used as output by the decoder.
  *
  */
diff --git a/libavcodec/qsv.h b/libavcodec/qsv.h
index c156b08d07..8b8160a4b1 100644
--- a/libavcodec/qsv.h
+++ b/libavcodec/qsv.h
@@ -26,8 +26,10 @@ 
 #include "libavutil/buffer.h"
 
 /**
- * This struct is used for communicating QSV parameters between libavcodec and
- * the caller. It is managed by the caller and must be assigned to
+ * @ref md_doc_2context "Context" for communicating QSV parameters between libavcodec
+ * and the caller.
+ *
+ * It is managed by the caller and must be assigned to
  * AVCodecContext.hwaccel_context.
  * - decoding: hwaccel_context must be set on return from the get_format()
  *             callback
diff --git a/libavcodec/sbr.h b/libavcodec/sbr.h
index fe3a39603a..98ad9024a9 100644
--- a/libavcodec/sbr.h
+++ b/libavcodec/sbr.h
@@ -116,7 +116,7 @@  typedef struct SBRData {
 typedef struct SpectralBandReplication SpectralBandReplication;
 
 /**
- * aacsbr functions pointers
+ * aacsbr functions pointer @ref md_doc_2context "context"
  */
 typedef struct AACSBRContext {
     int (*sbr_lf_gen)(SpectralBandReplication *sbr,
diff --git a/libavcodec/vdpau.h b/libavcodec/vdpau.h
index 8021c25761..227b85727d 100644
--- a/libavcodec/vdpau.h
+++ b/libavcodec/vdpau.h
@@ -64,8 +64,9 @@  typedef int (*AVVDPAU_Render2)(struct AVCodecContext *, struct AVFrame *,
                                const VdpBitstreamBuffer *);
 
 /**
- * This structure is used to share data between the libavcodec library and
+ * @ref md_doc_2context "Context" to share data between the libavcodec library and
  * the client video application.
+ *
  * This structure will be allocated and stored in AVCodecContext.hwaccel_context
  * by av_vdpau_bind_context(). Members can be set by the user once
  * during initialization or through each AVCodecContext.get_buffer()
diff --git a/libavcodec/videotoolbox.h b/libavcodec/videotoolbox.h
index d68d76e400..f15e79f325 100644
--- a/libavcodec/videotoolbox.h
+++ b/libavcodec/videotoolbox.h
@@ -49,8 +49,9 @@ 
 #include "libavutil/attributes.h"
 
 /**
- * This struct holds all the information that needs to be passed
- * between the caller and libavcodec for initializing Videotoolbox decoding.
+ * @ref md_doc_2context "Context" for information passed between the caller and libavcodec
+ * for initializing Videotoolbox decoding.
+ *
  * Its size is not a part of the public ABI, it must be allocated with
  * av_videotoolbox_alloc_context() and freed with av_free().
  */
diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
index a34e61f23c..54b5f9dc43 100644
--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -403,7 +403,7 @@  unsigned avfilter_filter_pad_count(const AVFilter *filter, int is_output);
  */
 #define AVFILTER_THREAD_SLICE (1 << 0)
 
-/** An instance of a filter */
+/** @ref md_doc_2context "Context" for a filter */
 struct AVFilterContext {
     const AVClass *av_class;        ///< needed for av_log() and filters common options
 
diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index 8afdcd9fd0..28243c06c4 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -1241,7 +1241,8 @@  enum AVDurationEstimationMethod {
 };
 
 /**
- * Format I/O context.
+ * Format I/O @ref md_doc_2context "context"
+ *
  * New fields can be added to the end with minor version bumps.
  * Removal, reordering and changes to existing fields require a major
  * version bump.
diff --git a/libavformat/avio.h b/libavformat/avio.h
index ebf611187d..b525c93194 100644
--- a/libavformat/avio.h
+++ b/libavformat/avio.h
@@ -146,7 +146,8 @@  enum AVIODataMarkerType {
 };
 
 /**
- * Bytestream IO Context.
+ * Bytestream I/O @ref md_doc_2context "context"
+ *
  * New public fields can be added with minor version bumps.
  * Removal, reordering and changes to existing public fields require
  * a major version bump.
diff --git a/libavutil/hwcontext.h b/libavutil/hwcontext.h
index bac30debae..60064cf08b 100644
--- a/libavutil/hwcontext.h
+++ b/libavutil/hwcontext.h
@@ -41,12 +41,13 @@  enum AVHWDeviceType {
 };
 
 /**
- * This struct aggregates all the (hardware/vendor-specific) "high-level" state,
- * i.e. state that is not tied to a concrete processing configuration.
- * E.g., in an API that supports hardware-accelerated encoding and decoding,
- * this struct will (if possible) wrap the state that is common to both encoding
- * and decoding and from which specific instances of encoders or decoders can be
- * derived.
+ * @ref md_doc_2context "Context" for (hardware/vendor-specific) "high-level" state.
+ *
+ * "High-level state" is anything that is not tied to a concrete processing
+ * configuration. E.g., in an API that supports hardware-accelerated encoding
+ * and decoding, this struct will (if possible) wrap the state that is common
+ * to both encoding and decoding and from which specific instances of encoders
+ * or decoders can be derived.
  *
  * This struct is reference-counted with the AVBuffer mechanism. The
  * av_hwdevice_ctx_alloc() constructor yields a reference, whose data field
@@ -103,9 +104,11 @@  typedef struct AVHWDeviceContext {
 } AVHWDeviceContext;
 
 /**
- * This struct describes a set or pool of "hardware" frames (i.e. those with
- * data not located in normal system memory). All the frames in the pool are
- * assumed to be allocated in the same way and interchangeable.
+ * @ref md_doc_2context "context" for a pool of "hardware" frames (those with
+ * data not located in normal system memory)
+ *
+ * All the frames in the pool are assumed to be allocated in the same way and
+ * interchangeable.
  *
  * This struct is reference-counted with the AVBuffer mechanism and tied to a
  * given AVHWDeviceContext instance. The av_hwframe_ctx_alloc() constructor
diff --git a/libavutil/hwcontext_cuda.h b/libavutil/hwcontext_cuda.h
index cbad434fea..e259892688 100644
--- a/libavutil/hwcontext_cuda.h
+++ b/libavutil/hwcontext_cuda.h
@@ -37,7 +37,7 @@ 
 typedef struct AVCUDADeviceContextInternal AVCUDADeviceContextInternal;
 
 /**
- * This struct is allocated as AVHWDeviceContext.hwctx
+ * This @ref md_doc_2context "context" is allocated as AVHWDeviceContext.hwctx
  */
 typedef struct AVCUDADeviceContext {
     CUcontext cuda_ctx;
diff --git a/libavutil/hwcontext_d3d11va.h b/libavutil/hwcontext_d3d11va.h
index 77d2d72f1b..101d1cb6f8 100644
--- a/libavutil/hwcontext_d3d11va.h
+++ b/libavutil/hwcontext_d3d11va.h
@@ -40,7 +40,7 @@ 
 #include <stdint.h>
 
 /**
- * This struct is allocated as AVHWDeviceContext.hwctx
+ * This @ref md_doc_2context "context" is allocated as AVHWDeviceContext.hwctx
  */
 typedef struct AVD3D11VADeviceContext {
     /**
@@ -126,7 +126,7 @@  typedef struct AVD3D11FrameDescriptor {
 } AVD3D11FrameDescriptor;
 
 /**
- * This struct is allocated as AVHWFramesContext.hwctx
+ * This @ref md_doc_2context "context" is allocated as AVHWFramesContext.hwctx
  */
 typedef struct AVD3D11VAFramesContext {
     /**
diff --git a/libavutil/hwcontext_d3d12va.h b/libavutil/hwcontext_d3d12va.h
index ff06e6f2ef..c623914c2b 100644
--- a/libavutil/hwcontext_d3d12va.h
+++ b/libavutil/hwcontext_d3d12va.h
@@ -37,7 +37,7 @@ 
 #include <d3d12video.h>
 
 /**
- * @brief This struct is allocated as AVHWDeviceContext.hwctx
+ * @brief This @ref md_doc_2context "context" is allocated as AVHWDeviceContext.hwctx
  *
  */
 typedef struct AVD3D12VADeviceContext {
@@ -78,7 +78,7 @@  typedef struct AVD3D12VADeviceContext {
 } AVD3D12VADeviceContext;
 
 /**
- * @brief This struct is used to sync d3d12 execution
+ * @brief This @ref md_doc_2context "context" is used to sync d3d12 execution
  *
  */
 typedef struct AVD3D12VASyncContext {
@@ -120,7 +120,7 @@  typedef struct AVD3D12VAFrame {
 } AVD3D12VAFrame;
 
 /**
- * @brief This struct is allocated as AVHWFramesContext.hwctx
+ * @brief This @ref md_doc_2context "context" is allocated as AVHWFramesContext.hwctx
  *
  */
 typedef struct AVD3D12VAFramesContext {
diff --git a/libavutil/hwcontext_drm.h b/libavutil/hwcontext_drm.h
index 42709f215e..8329e69966 100644
--- a/libavutil/hwcontext_drm.h
+++ b/libavutil/hwcontext_drm.h
@@ -152,7 +152,7 @@  typedef struct AVDRMFrameDescriptor {
 /**
  * DRM device.
  *
- * Allocated as AVHWDeviceContext.hwctx.
+ * This @ref md_doc_2context "context" is allocated as AVHWDeviceContext.hwctx.
  */
 typedef struct AVDRMDeviceContext {
     /**
diff --git a/libavutil/hwcontext_dxva2.h b/libavutil/hwcontext_dxva2.h
index e1b79bc0de..c679c16af0 100644
--- a/libavutil/hwcontext_dxva2.h
+++ b/libavutil/hwcontext_dxva2.h
@@ -34,14 +34,14 @@ 
 #include <dxva2api.h>
 
 /**
- * This struct is allocated as AVHWDeviceContext.hwctx
+ * This @ref md_doc_2context "context" is allocated as AVHWDeviceContext.hwctx
  */
 typedef struct AVDXVA2DeviceContext {
     IDirect3DDeviceManager9 *devmgr;
 } AVDXVA2DeviceContext;
 
 /**
- * This struct is allocated as AVHWFramesContext.hwctx
+ * This @ref md_doc_2context "context" is allocated as AVHWFramesContext.hwctx
  */
 typedef struct AVDXVA2FramesContext {
     /**
diff --git a/libavutil/hwcontext_mediacodec.h b/libavutil/hwcontext_mediacodec.h
index fc0263cabc..e81193247b 100644
--- a/libavutil/hwcontext_mediacodec.h
+++ b/libavutil/hwcontext_mediacodec.h
@@ -22,7 +22,7 @@ 
 /**
  * MediaCodec details.
  *
- * Allocated as AVHWDeviceContext.hwctx
+ * This @ref md_doc_2context "context" is allocated as AVHWDeviceContext.hwctx
  */
 typedef struct AVMediaCodecDeviceContext {
     /**
diff --git a/libavutil/hwcontext_opencl.h b/libavutil/hwcontext_opencl.h
index ef54486c95..7abd97db2b 100644
--- a/libavutil/hwcontext_opencl.h
+++ b/libavutil/hwcontext_opencl.h
@@ -58,7 +58,7 @@  typedef struct AVOpenCLFrameDescriptor {
 /**
  * OpenCL device details.
  *
- * Allocated as AVHWDeviceContext.hwctx
+ * This @ref md_doc_2context "context" is allocated as AVHWDeviceContext.hwctx
  */
 typedef struct AVOpenCLDeviceContext {
     /**
@@ -84,7 +84,7 @@  typedef struct AVOpenCLDeviceContext {
 /**
  * OpenCL-specific data associated with a frame pool.
  *
- * Allocated as AVHWFramesContext.hwctx.
+ * This @ref md_doc_2context "context" is allocated as AVHWFramesContext.hwctx.
  */
 typedef struct AVOpenCLFramesContext {
     /**
diff --git a/libavutil/hwcontext_qsv.h b/libavutil/hwcontext_qsv.h
index e2dba8ad83..b63ebddaef 100644
--- a/libavutil/hwcontext_qsv.h
+++ b/libavutil/hwcontext_qsv.h
@@ -30,7 +30,7 @@ 
  */
 
 /**
- * This struct is allocated as AVHWDeviceContext.hwctx
+ * This @ref md_doc_2context "context" is allocated as AVHWDeviceContext.hwctx
  */
 typedef struct AVQSVDeviceContext {
     mfxSession session;
@@ -48,7 +48,7 @@  typedef struct AVQSVDeviceContext {
 } AVQSVDeviceContext;
 
 /**
- * This struct is allocated as AVHWFramesContext.hwctx
+ * This @ref md_doc_2context "context" is allocated as AVHWFramesContext.hwctx
  */
 typedef struct AVQSVFramesContext {
     mfxFrameSurface1 *surfaces;
diff --git a/libavutil/hwcontext_vaapi.h b/libavutil/hwcontext_vaapi.h
index 0b2e071cb3..4a897eb851 100644
--- a/libavutil/hwcontext_vaapi.h
+++ b/libavutil/hwcontext_vaapi.h
@@ -63,7 +63,7 @@  enum {
 /**
  * VAAPI connection details.
  *
- * Allocated as AVHWDeviceContext.hwctx
+ * This @ref md_doc_2context "context" is allocated as AVHWDeviceContext.hwctx
  */
 typedef struct AVVAAPIDeviceContext {
     /**
@@ -83,7 +83,7 @@  typedef struct AVVAAPIDeviceContext {
 /**
  * VAAPI-specific data associated with a frame pool.
  *
- * Allocated as AVHWFramesContext.hwctx.
+ * This @ref md_doc_2context "context" is allocated as AVHWFramesContext.hwctx.
  */
 typedef struct AVVAAPIFramesContext {
     /**
@@ -105,7 +105,7 @@  typedef struct AVVAAPIFramesContext {
 /**
  * VAAPI hardware pipeline configuration details.
  *
- * Allocated with av_hwdevice_hwconfig_alloc().
+ * This struct is allocated with av_hwdevice_hwconfig_alloc().
  */
 typedef struct AVVAAPIHWConfig {
     /**
diff --git a/libavutil/hwcontext_vdpau.h b/libavutil/hwcontext_vdpau.h
index 1b7ea1e443..e305caa595 100644
--- a/libavutil/hwcontext_vdpau.h
+++ b/libavutil/hwcontext_vdpau.h
@@ -30,7 +30,7 @@ 
  */
 
 /**
- * This struct is allocated as AVHWDeviceContext.hwctx
+ * This @ref md_doc_2context "context" is allocated as AVHWDeviceContext.hwctx
  */
 typedef struct AVVDPAUDeviceContext {
     VdpDevice          device;
diff --git a/libavutil/hwcontext_vulkan.h b/libavutil/hwcontext_vulkan.h
index cbbd2390c1..1869870032 100644
--- a/libavutil/hwcontext_vulkan.h
+++ b/libavutil/hwcontext_vulkan.h
@@ -39,7 +39,7 @@  typedef struct AVVkFrame AVVkFrame;
  */
 
 /**
- * Main Vulkan context, allocated as AVHWDeviceContext.hwctx.
+ * Main Vulkan @ref md_doc_2context "context", allocated as AVHWDeviceContext.hwctx.
  * All of these can be set before init to change what the context uses
  */
 typedef struct AVVulkanDeviceContext {
@@ -172,7 +172,7 @@  typedef enum AVVkFrameFlags {
 } AVVkFrameFlags;
 
 /**
- * Allocated as AVHWFramesContext.hwctx, used to set pool-specific options
+ * This @ref md_doc_2context "context" is allocated as AVHWFramesContext.hwctx, used to set pool-specific options
  */
 typedef struct AVVulkanFramesContext {
     /**