This uses a new MMAL feature, which limits the number of extra frames
that can be buffered within the decoder. VIDEO_MAX_NUM_CALLBACKS can
be defined as positive or negative number. Positive numbers are
absolute, and can lead to deadlocks if the user underestimates the
number of required buffers. Negative numbers specify the number of extra
buffers, e.g. -1 means no extra buffer, (-1-N) means N extra buffers.
Set a gratuitous default of -11 (N=10). This is much lower than the
firmware default, which appears to be 96.
This is backwards compatible, but needs a symbol only present in newer
firmware headers. (It's an enum item, so it requires a check in
configure.)
---
configure | 2 ++
libavcodec/mmaldec.c | 9 +++++++++
2 files changed, 11 insertions(+)
diff --git a/configure b/configure
index e6ed7e0..a8cd1d9 100755
--- a/configure
+++ b/configure
@@ -1645,6 +1645,7 @@ HAVE_LIST="
libc_msvcrt
libdc1394_1
libdc1394_2
+ MMAL_PARAMETER_VIDEO_MAX_NUM_CALLBACKS
sdl
section_data_rel_ro
threads
@@ -4631,6 +4632,7 @@ enabled mmal && { check_lib
interface/mmal/mmal.h mmal_port_connect
check_lib interface/mmal/mmal.h
mmal_port_connect ; }
check_lib interface/mmal/mmal.h
mmal_port_connect ; } ||
die "ERROR: mmal not found"; }
+enabled mmal && check_func_headers interface/mmal/mmal.h
"MMAL_PARAMETER_VIDEO_MAX_NUM_CALLBACKS"
enabled omx_rpi && enable omx
enabled omx && { check_header OMX_Core.h ||
{ ! enabled cross_compile && enabled omx_rpi
&& {
diff --git a/libavcodec/mmaldec.c b/libavcodec/mmaldec.c
index 42c3492..f852c07 100644
--- a/libavcodec/mmaldec.c
+++ b/libavcodec/mmaldec.c
@@ -67,6 +67,7 @@ typedef struct FFBufferRef {
typedef struct MMALDecodeContext {
AVClass *av_class;
int extra_buffers;
+ int extra_decoder_buffers;
MMAL_COMPONENT_T *decoder;
MMAL_QUEUE_T *queue_decoded_frames;
@@ -383,6 +384,13 @@ static av_cold int ffmmal_init_decoder(AVCodecContext
*avctx)
av_get_codec_tag_string(tmp, sizeof(tmp), format_in->encoding);
av_log(avctx, AV_LOG_DEBUG, "Using MMAL %s encoding.\n", tmp);
+#if HAVE_MMAL_PARAMETER_VIDEO_MAX_NUM_CALLBACKS
+ if (mmal_port_parameter_set_uint32(decoder->input[0],
MMAL_PARAMETER_VIDEO_MAX_NUM_CALLBACKS,
+ -1 - ctx->extra_decoder_buffers)) {
+ av_log(avctx, AV_LOG_WARNING, "Could not set input buffering
limit.\n");
+ }
+#endif
+
if ((status = mmal_port_format_commit(decoder->input[0])))
goto fail;
@@ -806,6 +814,7 @@ AVHWAccel ff_vc1_mmal_hwaccel = {
static const AVOption options[]={
{"extra_buffers", "extra buffers", offsetof(MMALDecodeContext,
extra_buffers), AV_OPT_TYPE_INT, {.i64 = 10}, 0, 256, 0},
+ {"extra_decoder_buffers", "extra MMAL internal buffered frames",
offsetof(MMALDecodeContext, extra_decoder_buffers), AV_OPT_TYPE_INT, {.i64 =
10}, 0, 256, 0},
{NULL}
};
--
2.8.0.rc3
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