gstreamer/subprojects/gst-plugins-good/ext/libpng/gstpngenc.h
Jordan Petridis 1ef13dda12 pngenc: Allocate a single GstMemory per frame
Previously, we would create a new GstMemory per write operation
and then append them to the GstBuffer. This would cause a reallocation
every 16 Memories which is an issue since the png encoder will usually
do write in a pattern of 4, 8 and 8k bytes repeating until the frame
is done.

Instead allocate a single GstMemory and keep writting it into it
with a manual index. Much like the jpegenc does.

Doing some basic testing With a testsrc snow pattern at 4k and 8k
the same pipeline would take ~3.30s to encode a 4k frame and ~23s
for an 8k. At 4k 0.70s/33% is taken by memory allocations, while at
8k its ~10.5s/45%.

With this patch, at 4k the pipeline takes ~2.40s and at 8k only 9.60s
making this 28% and 58% faster accordingly on my laptop, and
allocation runtime is dropped to subsecond times.

Here's the test pipeline used, increase num-buffers in image freeze
to gather more samples.

```
gst-launch-1.0 videotestsrc num-buffers=1 pattern=snow ! imagefreeze num-buffers=1 ! \
  video/x-raw,width=7680,height=4320 ! pngenc ! fakesink
```

Close #2717

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4944>
2023-07-05 08:41:14 +00:00

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C

/* GStreamer
* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
* Copyright (C) 2012 Collabora Ltd.
* Author : Edward Hervey <edward@collabora.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifndef __GST_PNGENC_H__
#define __GST_PNGENC_H__
#include <gst/gst.h>
#include <gst/video/gstvideoencoder.h>
#include <png.h>
G_BEGIN_DECLS
#define GST_TYPE_PNGENC (gst_pngenc_get_type())
G_DECLARE_FINAL_TYPE (GstPngEnc, gst_pngenc, GST, PNGENC, GstVideoEncoder)
struct _GstPngEnc
{
GstVideoEncoder parent;
GstVideoCodecState *input_state;
GstMemory *output_mem;
GstMapInfo output_map;
gsize output_mem_pos;
png_structp png_struct_ptr;
png_infop png_info_ptr;
gint png_color_type;
gint depth;
guint compression_level;
gboolean snapshot;
gboolean newmedia;
};
GST_ELEMENT_REGISTER_DECLARE (pngenc);
G_END_DECLS
#endif /* __GST_PNGENC_H__ */