[FFmpeg-devel] [PATCH 01/13] lavc: Add codec metadata to indicate hardware support

[Mark Thompson]

---
 doc/APIchanges       |  3 +++
 libavcodec/avcodec.h | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 libavcodec/hwaccel.h | 18 +++++++++++++
 libavcodec/utils.c   | 12 +++++++++
 4 files changed, 107 insertions(+)

diff --git a/doc/APIchanges b/doc/APIchanges
index d336f6ce22..a3c5e21765 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -15,6 +15,9 @@ libavutil:     2017-10-21
 
 API changes, most recent first:
 
+2017-xx-xx - xxxxxxx - lavc 58.x+1.0 - avcodec.h
+  Add AVCodecHWConfig and avcodec_get_hw_config().
+
 2017-xx-xx - xxxxxxx - lavc 58.3.100 - avcodec.h
   Add avcodec_get_hw_frames_parameters().
 
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 442b558d4b..5bbeb67a0d 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -36,6 +36,7 @@
 #include "libavutil/channel_layout.h"
 #include "libavutil/dict.h"
 #include "libavutil/frame.h"
+#include "libavutil/hwcontext.h"
 #include "libavutil/log.h"
 #include "libavutil/pixfmt.h"
 #include "libavutil/rational.h"
@@ -3279,6 +3280,61 @@ typedef struct AVProfile {
     const char *name; ///< short name for the profile
 } AVProfile;
 
+enum {
+    /**
+     * The codec supports this format via the hw_device_ctx interface.
+     *
+     * When selecting this format, AVCodecContext.hw_device_ctx should
+     * have been set to a device of the specified type before calling
+     * avcodec_open2().
+     */
+    AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX = 0x01,
+    /**
+     * The codec supports this format via the hw_frames_ctx interface.
+     *
+     * When selecting this format for a decoder,
+     * AVCodecContext.hw_frames_ctx should be set to a suitable frames
+     * context inside the get_format() callback.  The frames context
+     * must have been created on a device of the specified type.
+     */
+    AV_CODEC_HW_CONFIG_METHOD_HW_FRAMES_CTX = 0x02,
+    /**
+     * The codec supports this format by some internal method.
+     *
+     * This format can be selected without any additional configuration -
+     * no device or frames context is required.
+     */
+    AV_CODEC_HW_CONFIG_METHOD_INTERNAL      = 0x04,
+    /**
+     * The codec supports this format by some ad-hoc method.
+     *
+     * Additional settings and/or function calls are required.  See the
+     * codec-specific documentation for details.  (Methods requiring
+     * this sort of configuration are deprecated and others should be
+     * used in preference.)
+     */
+    AV_CODEC_HW_CONFIG_METHOD_AD_HOC        = 0x08,
+};
+
+typedef struct AVCodecHWConfig {
+    /**
+     * A hardware pixel format which the codec can use.
+     */
+    enum AVPixelFormat pix_fmt;
+    /**
+     * Bit set of AV_CODEC_HW_CONFIG_METHOD_* flags, describing the possible
+     * setup methods which can be used with this configuration.
+     */
+    int methods;
+    /**
+     * The device type associated with the configuration.
+     *
+     * Must be set for AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX and
+     * AV_CODEC_HW_CONFIG_METHOD_HW_FRAMES_CTX, otherwise unused.
+     */
+    enum AVHWDeviceType device_type;
+} AVCodecHWConfig;
+
 typedef struct AVCodecDefault AVCodecDefault;
 
 struct AVSubtitle;
@@ -3404,6 +3460,15 @@ typedef struct AVCodec {
      * packets before decoding.
      */
     const char *bsfs;
+
+    /**
+     * Array of pointers to hardware configurations supported by the codec,
+     * or NULL if no hardware supported.  The array is terminated by a NULL
+     * pointer.
+     *
+     * The user can only access this field via avcodec_get_hw_config().
+     */
+    const struct AVCodecHWConfigInternal **hw_configs;
 } AVCodec;
 
 #if FF_API_CODEC_GET_SET
@@ -3414,6 +3479,15 @@ int av_codec_get_max_lowres(const AVCodec *codec);
 struct MpegEncContext;
 
 /**
+ * Retrieve supported hardware configurations for a codec.
+ *
+ * Values of index from zero to some maximum return the indexed configuration
+ * descriptor; all other values return NULL.  If the codec does not support
+ * any hardware configurations then it will always return NULL.
+ */
+const AVCodecHWConfig *avcodec_get_hw_config(const AVCodec *codec, int index);
+
+/**
  * @defgroup lavc_hwaccel AVHWAccel
  * @{
  */
diff --git a/libavcodec/hwaccel.h b/libavcodec/hwaccel.h
index 124fbbf1fd..0198c7f858 100644
--- a/libavcodec/hwaccel.h
+++ b/libavcodec/hwaccel.h
@@ -19,6 +19,24 @@
 #ifndef AVCODEC_HWACCEL_H
 #define AVCODEC_HWACCEL_H
 
+#include "avcodec.h"
+
+
 #define HWACCEL_CAP_ASYNC_SAFE      (1 << 0)
 
+
+typedef struct AVCodecHWConfigInternal {
+    /**
+     * This is the structure which will be returned to the user by
+     * avcodec_get_hw_config().
+     */
+    AVCodecHWConfig public;
+    /**
+     * If this configuration uses a hwaccel, a pointer to it.
+     * If not, NULL.
+     */
+    const AVHWAccel *hwaccel;
+} AVCodecHWConfigInternal;
+
+
 #endif /* AVCODEC_HWACCEL_H */
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index e50de6e89b..01bf7556f7 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -45,6 +45,7 @@
 #include "libavutil/thread.h"
 #include "avcodec.h"
 #include "decode.h"
+#include "hwaccel.h"
 #include "libavutil/opt.h"
 #include "me_cmp.h"
 #include "mpegvideo.h"
@@ -1885,6 +1886,17 @@ int ff_match_2uint16(const uint16_t(*tab)[2], int size, int a, int b)
     return i;
 }
 
+const AVCodecHWConfig *avcodec_get_hw_config(const AVCodec *codec, int index)
+{
+    int i;
+    if (!codec->hw_configs || index < 0)
+        return NULL;
+    for (i = 0; i < index; i++)
+        if (!codec->hw_configs[i])
+            return NULL;
+    return &codec->hw_configs[index]->public;
+}
+
 static AVHWAccel *first_hwaccel = NULL;
 static AVHWAccel **last_hwaccel = &first_hwaccel;
 
-- 
2.11.0