path: root/stream/stream_avdevice.c
diff options
authorwm4 <wm4@nowhere>2012-11-30 18:41:04 +0100
committerwm4 <wm4@nowhere>2012-12-03 21:08:51 +0100
commitdd3260185ac4a04277fc550ca2206cc29bf68bc6 (patch)
treea8c6b4365c8fdc8fad13e58d04b85639e0f4fb01 /stream/stream_avdevice.c
parentaa2c07542f11ee8ab6df0949635ee453952213dd (diff)
demux_lavf: add support for libavdevice
libavdevice supports various "special" video and audio inputs, such as screen-capture or libavfilter filter graphs. libavdevice inputs are implemented as demuxers. They don't use the custom stream callbacks (in AVFormatContext.pb). Instead, input parameters are passed as filename. This means the mpv stream layer has to be disabled. Do this by adding the pseudo stream handler avdevice://, whose only purpose is passing the filename to demux_lavf, without actually doing anything. Change the logic how the filename is passed to libavformat. Remove handling of the filename from demux_open_lavf() and move it to lavf_check_file(). (This also fixes a possible bug when skipping the "lavf://" prefix.) libavdevice now can be invoked by specifying demuxer and args as in: mpv avdevice://demuxer:args The args are passed as filename to libavformat. When using libavdevice demuxers, their actual meaning is highly implementation specific. They don't refer to actual filenames. Note: libavdevice is disabled by default. There is one problem: libavdevice pulls in libavfilter, which in turn causes symbol clashes with mpv internals. The problem is that libavfilter includes a mplayer filter bridge, which is used to interface with a set of nearly unmodified mplayer filters copied into libavfilter. This filter bridge uses the same symbol names as mplayer/mpv's filter chain, which results in symbol clashes at link-time. This can be prevented by building ffmpeg with --disable-filter=mp, but unfortunately this is not the default. This means linking to libavdevice (which in turn forces linking with libavfilter by default) must be disabled. We try doing this by compiling a test file that defines one of the clashing symbols (vf_mpi_clear). To enable libavdevice input, ffmpeg should be built with the options: --disable-filter=mp and mpv with: --enable-libavdevice Originally, I tried to auto-detect it. But the resulting complications in configure did't seem worth the trouble.
Diffstat (limited to 'stream/stream_avdevice.c')
1 files changed, 49 insertions, 0 deletions
diff --git a/stream/stream_avdevice.c b/stream/stream_avdevice.c
new file mode 100644
index 0000000000..e26d5a9060
--- /dev/null
+++ b/stream/stream_avdevice.c
@@ -0,0 +1,49 @@
+ * This file is part of mpv.
+ *
+ * mpv is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * mpv is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with mpv; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#include "config.h"
+#include "stream.h"
+#include "demux/demux.h"
+static int fill_buffer(stream_t *s, char *buffer, int max_len)
+ return -1;
+static int open_f(stream_t *stream, int mode, void *opts, int *file_format)
+ if (mode != STREAM_READ)
+ return STREAM_ERROR;
+ stream->fill_buffer = fill_buffer;
+ stream->type = STREAMTYPE_AVDEVICE;
+ *file_format = DEMUXER_TYPE_LAVF;
+ return STREAM_OK;
+const stream_info_t stream_info_avdevice = {
+ .info = "FFmpeg libavdevice",
+ .name = "avdevice",
+ .author = "",
+ .comment =
+ "Force a libavformat/libavdevice demuxer with avdevice://demuxer:args",
+ .open = open_f,
+ .protocols = { "avdevice", "av", NULL },