avcodec/mediacodec: add av_mediacodec_render_buffer_at_time()

The existing av_mediacodec_release_buffer allows the user to render
or discard the Surface-backed frame. This new method allows the user
to control exactly when the frame will be rendered to its SurfaceView.

Available since Android API 21.
Signed-off-by: Aman Gupta <aman@tmm1.net>

doc/APIchanges

@@ -15,6 +15,9 @@ libavutil:     2017-10-21
 
 API changes, most recent first:
 
+2018-10-11 - xxxxxxxxxx - lavc 58.33.100 - mediacodec.h
+  Add av_mediacodec_render_buffer_at_time().
+
 2018-09-09 - xxxxxxxxxx - lavc 58.29.100 - avcodec.h
   Add AV_PKT_DATA_AFD
 

libavcodec/mediacodec.c

@@ -102,6 +102,22 @@ int av_mediacodec_release_buffer(AVMediaCodecBuffer *buffer, int render)
     return 0;
 }
 
+int av_mediacodec_render_buffer_at_time(AVMediaCodecBuffer *buffer, int64_t time)
+{
+    MediaCodecDecContext *ctx = buffer->ctx;
+    int released = atomic_fetch_add(&buffer->released, 1);
+
+    if (!released && (ctx->delay_flush || buffer->serial == atomic_load(&ctx->serial))) {
+        atomic_fetch_sub(&ctx->hw_buffer_count, 1);
+        av_log(ctx->avctx, AV_LOG_DEBUG,
+               "Rendering output buffer %zd (%p) ts=%"PRId64" with time=%"PRId64" [%d pending]\n",
+               buffer->index, buffer, buffer->pts, time, atomic_load(&ctx->hw_buffer_count));
+        return ff_AMediaCodec_releaseOutputBufferAtTime(ctx->codec, buffer->index, time);
+    }
+
+    return 0;
+}
+
 #else
 
 #include <stdlib.h>
@@ -125,4 +141,9 @@ int av_mediacodec_release_buffer(AVMediaCodecBuffer *buffer, int render)
     return AVERROR(ENOSYS);
 }
 
+int av_mediacodec_render_buffer_at_time(AVMediaCodecBuffer *buffer, int64_t time)
+{
+    return AVERROR(ENOSYS);
+}
+
 #endif

libavcodec/mediacodec.h

@@ -85,4 +85,17 @@ typedef struct MediaCodecBuffer AVMediaCodecBuffer;
  */
 int av_mediacodec_release_buffer(AVMediaCodecBuffer *buffer, int render);
 
+/**
+ * Release a MediaCodec buffer and render it at the given time to the surface
+ * that is associated with the decoder. The timestamp must be within one second
+ * of the current java/lang/System#nanoTime() (which is implemented using
+ * CLOCK_MONOTONIC on Android). See the Android MediaCodec documentation
+ * of android/media/MediaCodec#releaseOutputBuffer(int,long) for more details.
+ *
+ * @param buffer the buffer to render
+ * @param time timestamp in nanoseconds of when to render the buffer
+ * @return 0 on success, < 0 otherwise
+ */
+int av_mediacodec_render_buffer_at_time(AVMediaCodecBuffer *buffer, int64_t time);
+
 #endif /* AVCODEC_MEDIACODEC_H */

libavcodec/mediacodec_wrapper.c

@@ -1432,7 +1432,7 @@ int ff_AMediaCodec_releaseOutputBufferAtTime(FFAMediaCodec *codec, size_t idx, i
 
     JNI_GET_ENV_OR_RETURN(env, codec, AVERROR_EXTERNAL);
 
-    (*env)->CallVoidMethod(env, codec->object, codec->jfields.release_output_buffer_at_time_id, (jint)idx, timestampNs);
+    (*env)->CallVoidMethod(env, codec->object, codec->jfields.release_output_buffer_at_time_id, (jint)idx, (jlong)timestampNs);
     if (ff_jni_exception_check(env, 1, codec) < 0) {
         ret = AVERROR_EXTERNAL;
         goto fail;

libavcodec/version.h

@@ -28,7 +28,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVCODEC_VERSION_MAJOR  58
-#define LIBAVCODEC_VERSION_MINOR  32
+#define LIBAVCODEC_VERSION_MINOR  33
 #define LIBAVCODEC_VERSION_MICRO 100
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \