[FFmpeg-devel] [PATCH] avcodec: add drop_changed_frames
Gyan
ffmpeg at gyani.pro
Sun Apr 14 19:50:18 EEST 2019
Implemented this patch
http://www.ffmpeg.org/pipermail/ffmpeg-devel/2019-March/241733.html
in libavcodec as suggested by Michael
Gyan
P.S. will add doc/APIchanges entry after I have the hash.
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From bbc8ac18da560a59cd252bbb5c34dfa1fcc575b8 Mon Sep 17 00:00:00 2001
From: Gyan Doshi <ffmpeg at gyani.pro>
Date: Sun, 14 Apr 2019 22:12:25 +0530
Subject: [PATCH] avcodec: add drop_changed_frames
Discard decoded frames which differ from first decoded frame in stream.
---
doc/codecs.texi | 3 +++
libavcodec/avcodec.h | 18 ++++++++++++++
libavcodec/decode.c | 48 +++++++++++++++++++++++++++++++++++++-
libavcodec/options_table.h | 1 +
libavcodec/version.h | 2 +-
5 files changed, 70 insertions(+), 2 deletions(-)
diff --git a/doc/codecs.texi b/doc/codecs.texi
index 572e561c1a..327350453c 100644
--- a/doc/codecs.texi
+++ b/doc/codecs.texi
@@ -1249,6 +1249,9 @@ Note: The required alignment depends on if @code{AV_CODEC_FLAG_UNALIGNED} is set
CPU. @code{AV_CODEC_FLAG_UNALIGNED} cannot be changed from the command line. Also hardware
decoders will not apply left/top Cropping.
+ at item drop_changed_frames @var{bool} (@emph{decoding,audio,video})
+Drop decoded frames whose parameters are different with respect to the first decoded frame.
+Default is 0 (disabled).
@end table
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 9e37466641..9fc59abc98 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -3360,6 +3360,24 @@ typedef struct AVCodecContext {
* - encoding: unused
*/
int discard_damaged_percentage;
+
+ /**
+ * If drop_changed_frames is set, the parameters of the first decoded frame
+ * are stored in the initial_* fields. Any subsequent frame with differing
+ * parameters is dropped. Unset by default.
+ *
+ * @note only applicable with avcodec_receive_frame.
+ *
+ * - decoding: set by user
+ * - encoding: unused
+ */
+ int drop_changed_frames;
+ int changed_frames_dropped;
+ int initial_format;
+ int initial_width, initial_height;
+ int initial_sample_rate;
+ int initial_channels;
+ uint64_t initial_channel_layout;
} AVCodecContext;
#if FF_API_CODEC_GET_SET
diff --git a/libavcodec/decode.c b/libavcodec/decode.c
index a32ff2fcd3..50baa2105e 100644
--- a/libavcodec/decode.c
+++ b/libavcodec/decode.c
@@ -740,7 +740,7 @@ static int apply_cropping(AVCodecContext *avctx, AVFrame *frame)
int attribute_align_arg avcodec_receive_frame(AVCodecContext *avctx, AVFrame *frame)
{
AVCodecInternal *avci = avctx->internal;
- int ret;
+ int ret, changed;
av_frame_unref(frame);
@@ -765,6 +765,52 @@ int attribute_align_arg avcodec_receive_frame(AVCodecContext *avctx, AVFrame *fr
avctx->frame_number++;
+ if (avctx->drop_changed_frames &&
+ (avctx->codec_type == AVMEDIA_TYPE_VIDEO || avctx->codec_type == AVMEDIA_TYPE_AUDIO)) {
+
+ if (avctx->frame_number == 1) {
+ avctx->initial_format = frame->format;
+ switch(avctx->codec_type) {
+ case AVMEDIA_TYPE_VIDEO:
+ avctx->initial_width = frame->width;
+ avctx->initial_height = frame->height;
+ break;
+ case AVMEDIA_TYPE_AUDIO:
+ avctx->initial_sample_rate = frame->sample_rate ? frame->sample_rate :
+ avctx->sample_rate;
+ avctx->initial_channels = frame->channels;
+ avctx->initial_channel_layout = frame->channel_layout;
+ break;
+ }
+ }
+
+ if (avctx->frame_number > 1) {
+ changed = avctx->initial_format != frame->format;
+
+ switch(avctx->codec_type) {
+ case AVMEDIA_TYPE_VIDEO:
+ changed |= avctx->initial_width != frame->width ||
+ avctx->initial_height != frame->height;
+ break;
+ case AVMEDIA_TYPE_AUDIO:
+ changed |= avctx->initial_sample_rate != frame->sample_rate ||
+ avctx->initial_sample_rate != avctx->sample_rate ||
+ avctx->initial_channels != frame->channels ||
+ avctx->initial_channel_layout != frame->channel_layout;
+ break;
+ }
+
+ if (changed) {
+ avctx->changed_frames_dropped++;
+ av_log(avctx, AV_LOG_INFO, "dropped changed frame #%d pts %"PRId64
+ " drop count: %d \n",
+ avctx->frame_number, frame->pts,
+ avctx->changed_frames_dropped);
+ av_frame_unref(frame);
+ return AVERROR_INPUT_CHANGED;
+ }
+ }
+ }
return 0;
}
diff --git a/libavcodec/options_table.h b/libavcodec/options_table.h
index a3235bcd57..96e40005b4 100644
--- a/libavcodec/options_table.h
+++ b/libavcodec/options_table.h
@@ -480,6 +480,7 @@ static const AVOption avcodec_options[] = {
{"allow_profile_mismatch", "attempt to decode anyway if HW accelerated decoder's supported profiles do not exactly match the stream", 0, AV_OPT_TYPE_CONST, {.i64 = AV_HWACCEL_FLAG_ALLOW_PROFILE_MISMATCH }, INT_MIN, INT_MAX, V | D, "hwaccel_flags"},
{"extra_hw_frames", "Number of extra hardware frames to allocate for the user", OFFSET(extra_hw_frames), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, INT_MAX, V|D },
{"discard_damaged_percentage", "Percentage of damaged samples to discard a frame", OFFSET(discard_damaged_percentage), AV_OPT_TYPE_INT, {.i64 = 95 }, 0, 100, V|D },
+{"drop_changed_frames", "Drop frames whose parameters differ from first decoded frame", OFFSET(drop_changed_frames), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, A|V|D },
{NULL},
};
diff --git a/libavcodec/version.h b/libavcodec/version.h
index 1b60202dee..195e21bfbe 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -28,7 +28,7 @@
#include "libavutil/version.h"
#define LIBAVCODEC_VERSION_MAJOR 58
-#define LIBAVCODEC_VERSION_MINOR 51
+#define LIBAVCODEC_VERSION_MINOR 52
#define LIBAVCODEC_VERSION_MICRO 100
#define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
--
2.19.2
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