mirror of https://git.ffmpeg.org/ffmpeg.git
0bd1be65e8
The framework will allocate a buffer and copy the data to it, that takes time. But it avoids constently creating and destroyng the shared memory segment, and that saves more time. On my setup, from ~200 to ~300 FPS at full screen (1920×1200), from ~1400 to ~3300 at smaller size (640×480), similar to legacy x11grab and confirmed by others. Plus, shared memory segments are a scarce resource, allocating potentially many is a bad idea. Note: if the application were to drop all references to the buffer before the next call to av_read_frame(), then passing the shared memory segment as a refcounted buffer would be even more efficient, but it is hard to guarantee, and it does not happen with the ffmpeg command-line tool. Using a small number of preallocated buffers and resorting to a copy when the pool is exhausted would be a solution to get the better of both worlds. |
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|---|---|---|
| .. | ||
| tests | ||
| Makefile | ||
| alldevices.c | ||
| alsa.c | ||
| alsa.h | ||
| alsa_dec.c | ||
| alsa_enc.c | ||
| avdevice.c | ||
| avdevice.h | ||
| avdeviceres.rc | ||
| avfoundation.m | ||
| bktr.c | ||
| caca.c | ||
| decklink_common.cpp | ||
| decklink_common.h | ||
| decklink_common_c.h | ||
| decklink_dec.cpp | ||
| decklink_dec.h | ||
| decklink_dec_c.c | ||
| decklink_enc.cpp | ||
| decklink_enc.h | ||
| decklink_enc_c.c | ||
| dshow.c | ||
| dshow_capture.h | ||
| dshow_common.c | ||
| dshow_crossbar.c | ||
| dshow_enummediatypes.c | ||
| dshow_enumpins.c | ||
| dshow_filter.c | ||
| dshow_pin.c | ||
| dv1394.c | ||
| dv1394.h | ||
| fbdev_common.c | ||
| fbdev_common.h | ||
| fbdev_dec.c | ||
| fbdev_enc.c | ||
| file_open.c | ||
| gdigrab.c | ||
| iec61883.c | ||
| internal.h | ||
| jack.c | ||
| lavfi.c | ||
| libavdevice.v | ||
| libcdio.c | ||
| libdc1394.c | ||
| openal-dec.c | ||
| opengl_enc.c | ||
| opengl_enc_shaders.h | ||
| oss.c | ||
| oss.h | ||
| oss_dec.c | ||
| oss_enc.c | ||
| pulse_audio_common.c | ||
| pulse_audio_common.h | ||
| pulse_audio_dec.c | ||
| pulse_audio_enc.c | ||
| qtkit.m | ||
| sdl2.c | ||
| sndio.c | ||
| sndio.h | ||
| sndio_dec.c | ||
| sndio_enc.c | ||
| timefilter.c | ||
| timefilter.h | ||
| utils.c | ||
| v4l.c | ||
| v4l2-common.c | ||
| v4l2-common.h | ||
| v4l2.c | ||
| v4l2enc.c | ||
| version.h | ||
| vfwcap.c | ||
| x11grab.c | ||
| xcbgrab.c | ||
| xv.c | ||