Adds a new hwaccel flag REUSE_CONTEXT for the user to indicate that
this is desired, and adds an additional refcounted state structure
hwaccel_priv_persistent which persists across hwaccel reinitialisation
and can be used to store context information for reuse.
---
doc/APIchanges | 3 +++
libavcodec/avcodec.h | 6 ++++++
libavcodec/decode.c | 15 +++++++++++++--
libavcodec/internal.h | 8 ++++++++
libavcodec/pthread_frame.c | 9 +++++++++
libavcodec/utils.c | 1 +
6 files changed, 40 insertions(+), 2 deletions(-)
diff --git a/doc/APIchanges b/doc/APIchanges
index 6de6971fb..6f70f3c96 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -13,6 +13,9 @@ libavutil: 2017-03-23
API changes, most recent first:
+2017-xx-xx - xxxxxxx - lavc 58.x+1.0 - avcodec.h
+ Add AV_HWACCEL_FLAG_REUSE_CONTEXT.
+
2017-xx-xx - xxxxxxx - lavfi 7.x+1.0 - avfilter.h
Add AVFilterContext.extra_hw_frames.
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 680a7b5e4..89e432d16 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -3058,6 +3058,12 @@ typedef struct AVHWAccel {
#define AV_HWACCEL_FLAG_ALLOW_PROFILE_MISMATCH (1 << 2)
/**
+ * Hardware acceleration may reuse an existing context when a stream changes
+ * but parameters are still compatible.
+ */
+#define AV_HWACCEL_FLAG_REUSE_CONTEXT (1 << 3)
+
+/**
* @}
*/
diff --git a/libavcodec/decode.c b/libavcodec/decode.c
index 2f4ebd12a..c2cc009ff 100644
--- a/libavcodec/decode.c
+++ b/libavcodec/decode.c
@@ -672,7 +672,7 @@ static AVHWAccel *find_hwaccel(enum AVCodecID codec_id,
static int setup_hwaccel(AVCodecContext *avctx,
const enum AVPixelFormat fmt,
- const char *name)
+ const char *name, AVHWAccel *prev_hwaccel)
{
AVHWAccel *hwa = find_hwaccel(avctx->codec_id, fmt);
int ret = 0;
@@ -690,6 +690,12 @@ static int setup_hwaccel(AVCodecContext *avctx,
return AVERROR(ENOMEM);
}
+ if (hwa != prev_hwaccel) {
+ // Persistent context only applies to the same hwaccel, so
+ // unreference it if the hwaccel changes.
+ av_buffer_unref(&avctx->internal->hwaccel_priv_persistent);
+ }
+
avctx->hwaccel = hwa;
if (hwa->init) {
ret = hwa->init(avctx);
@@ -705,6 +711,7 @@ static int setup_hwaccel(AVCodecContext *avctx,
int ff_get_format(AVCodecContext *avctx, const enum AVPixelFormat *fmt)
{
+ AVHWAccel *prev_hwaccel;
const AVPixFmtDescriptor *desc;
enum AVPixelFormat *choices;
enum AVPixelFormat ret;
@@ -723,9 +730,13 @@ int ff_get_format(AVCodecContext *avctx, const enum
AVPixelFormat *fmt)
memcpy(choices, fmt, (n + 1) * sizeof(*choices));
+ prev_hwaccel = avctx->hwaccel;
+
for (;;) {
if (avctx->hwaccel && avctx->hwaccel->uninit)
avctx->hwaccel->uninit(avctx);
+ if (!(avctx->hwaccel_flags & AV_HWACCEL_FLAG_REUSE_CONTEXT))
+ av_buffer_unref(&avctx->internal->hwaccel_priv_persistent);
av_freep(&avctx->internal->hwaccel_priv_data);
avctx->hwaccel = NULL;
@@ -752,7 +763,7 @@ int ff_get_format(AVCodecContext *avctx, const enum
AVPixelFormat *fmt)
}
}
- if (!setup_hwaccel(avctx, ret, desc->name))
+ if (!setup_hwaccel(avctx, ret, desc->name, prev_hwaccel))
break;
/* Remove failed hwaccel from choices */
diff --git a/libavcodec/internal.h b/libavcodec/internal.h
index da1b2fa7d..c9f29d913 100644
--- a/libavcodec/internal.h
+++ b/libavcodec/internal.h
@@ -159,6 +159,14 @@ typedef struct AVCodecInternal {
void *hwaccel_priv_data;
/**
+ * Reference to any persistent private data for the current hwaccel.
+ *
+ * It will be unreferenced when the context is closed or when the hwaccel
+ * is changed, but persists across hwaccel uninitialisation.
+ */
+ AVBufferRef *hwaccel_priv_persistent;
+
+ /**
* checks API usage: after codec draining, flush is required to resume
operation
*/
int draining;
diff --git a/libavcodec/pthread_frame.c b/libavcodec/pthread_frame.c
index a72391ba3..90cd8492a 100644
--- a/libavcodec/pthread_frame.c
+++ b/libavcodec/pthread_frame.c
@@ -256,6 +256,14 @@ static int update_context_from_thread(AVCodecContext *dst,
AVCodecContext *src,
dst->hwaccel_context = src->hwaccel_context;
dst->internal->hwaccel_priv_data = src->internal->hwaccel_priv_data;
+ av_buffer_unref(&dst->internal->hwaccel_priv_persistent);
+ if (src->internal->hwaccel_priv_persistent) {
+ dst->internal->hwaccel_priv_persistent =
+ av_buffer_ref(src->internal->hwaccel_priv_persistent);
+ if (!dst->internal->hwaccel_priv_persistent)
+ return AVERROR(ENOMEM);
+ }
+
if (!!dst->hw_frames_ctx != !!src->hw_frames_ctx ||
(dst->hw_frames_ctx && dst->hw_frames_ctx->data !=
src->hw_frames_ctx->data)) {
av_buffer_unref(&dst->hw_frames_ctx);
@@ -634,6 +642,7 @@ void ff_frame_thread_free(AVCodecContext *avctx, int
thread_count)
av_freep(&p->avctx->slice_offset);
}
+ av_buffer_unref(&p->avctx->internal->hwaccel_priv_persistent);
av_buffer_unref(&p->avctx->hw_frames_ctx);
av_freep(&p->avctx->internal);
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index bc421f67f..e28cdb32d 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -758,6 +758,7 @@ av_cold int avcodec_close(AVCodecContext *avctx)
if (avctx->hwaccel && avctx->hwaccel->uninit)
avctx->hwaccel->uninit(avctx);
av_freep(&avctx->internal->hwaccel_priv_data);
+ av_buffer_unref(&avctx->internal->hwaccel_priv_persistent);
ff_decode_bsfs_uninit(avctx);
--
2.11.0
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