lavdev: add libavfilter virtual input device

This input device is to be considered still experimental, only video
output is supported.

Changelog

@@ -7,6 +7,7 @@ version next:
 - boxblur filter added
 - BWF muxer
 - Flash Screen Video 2 decoder
+- lavfi input device added
 
 
 version 0.8:

configure

@@ -1472,6 +1472,7 @@ dshow_indev_extralibs="-lpsapi -lole32 -lstrmiids -luuid"
 dv1394_indev_deps="dv1394 dv_demuxer"
 fbdev_indev_deps="linux_fb_h"
 jack_indev_deps="jack_jack_h sem_timedwait"
+lavfi_indev_deps="avfilter"
 libdc1394_indev_deps="libdc1394"
 openal_indev_deps="openal"
 oss_indev_deps_any="soundcard_h sys_soundcard_h"

doc/indevs.texi

@@ -133,6 +133,60 @@ $ jack_connect metro:120_bpm ffmpeg:input_1
 For more information read:
 @url{http://jackaudio.org/}
 
+@section lavfi
+
+Libavfilter input virtual device.
+
+This input device reads data from the open output pads of a libavfilter
+filtergraph.
+
+For each filtergraph open output, the input device will create a
+corresponding stream which is mapped to the generated output. Currently
+only video data is supported. The filtergraph is specified through the
+option @option{graph}.
+
+To enable this input device, you need to configure your builf with
+@code{--enable-libavfilter}.
+
+@subsection Options
+
+@table @option
+
+@item graph
+Specify the filtergraph to use as input. Each video open output must be
+labelled by a unique string of the form "out@var{N}", where @var{N} is a
+number starting from 0 corresponding to the mapped input stream
+generated by the device.
+The first unlabelled output is automatically assigned to the "out0"
+label, but all the others need to be specified explicitely.
+
+If not specified defaults to the filename specified for the input
+device.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Create a color video stream and play it back with @file{ffplay}:
+@example
+ffplay -f lavfi -graph "color=pink [out0]" dummy
+@end example
+
+@item
+As the previous example, but use filename for specifying the graph
+description, and omit the "out0" label:
+@example
+ffplay -f lavfi color=pink
+@end example
+
+@item
+Create three different video test filtered sources and play them:
+@example
+ffplay -f lavfi -graph "testsrc [out0]; testsrc,hflip [out1]; testsrc,negate [out2]" test3
+@end example
+@end itemize
+
 @section libdc1394
 
 IIDC1394 input device, based on libdc1394 and libraw1394.

libavdevice/Makefile

@@ -2,6 +2,7 @@ include $(SUBDIR)../config.mak
 
 NAME    = avdevice
 FFLIBS  = avformat avcodec avutil
+FFLIBS-$(CONFIG_LAVFI_INDEV) += avfilter
 
 HEADERS = avdevice.h
 
@@ -19,6 +20,7 @@ OBJS-$(CONFIG_DSHOW_INDEV)               += dshow.o dshow_enummediatypes.o \
 OBJS-$(CONFIG_DV1394_INDEV)              += dv1394.o
 OBJS-$(CONFIG_FBDEV_INDEV)               += fbdev.o
 OBJS-$(CONFIG_JACK_INDEV)                += jack_audio.o
+OBJS-$(CONFIG_LAVFI_INDEV)               += lavfi.o
 OBJS-$(CONFIG_OPENAL_INDEV)              += openal-dec.o
 OBJS-$(CONFIG_OSS_INDEV)                 += oss_audio.o
 OBJS-$(CONFIG_OSS_OUTDEV)                += oss_audio.o

libavdevice/alldevices.c

@@ -44,6 +44,7 @@ void avdevice_register_all(void)
     REGISTER_INDEV    (DV1394, dv1394);
     REGISTER_INDEV    (FBDEV, fbdev);
     REGISTER_INDEV    (JACK, jack);
+    REGISTER_INDEV    (LAVFI, lavfi);
     REGISTER_INDEV    (OPENAL, openal);
     REGISTER_INOUTDEV (OSS, oss);
     REGISTER_OUTDEV   (SDL, sdl);

libavdevice/avdevice.h

@@ -23,7 +23,7 @@
 #include "libavformat/avformat.h"
 
 #define LIBAVDEVICE_VERSION_MAJOR 53
-#define LIBAVDEVICE_VERSION_MINOR  2
+#define LIBAVDEVICE_VERSION_MINOR  3
 #define LIBAVDEVICE_VERSION_MICRO  0
 
 #define LIBAVDEVICE_VERSION_INT AV_VERSION_INT(LIBAVDEVICE_VERSION_MAJOR, \

libavdevice/lavfi.c

@@ -0,0 +1,282 @@
+/*
+ * Copyright (c) 2011 Stefano Sabatini
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * libavfilter virtual input device
+ */
+
+/* #define DEBUG */
+
+#include "float.h"              /* DBL_MIN, DBL_MAX */
+
+#include "libavutil/log.h"
+#include "libavutil/mem.h"
+#include "libavutil/opt.h"
+#include "libavutil/parseutils.h"
+#include "libavutil/pixdesc.h"
+#include "libavfilter/avfilter.h"
+#include "libavfilter/avfiltergraph.h"
+#include "libavfilter/vsink_buffer.h"
+#include "avdevice.h"
+
+typedef struct {
+    AVClass *class;          ///< class for private options
+    char          *graph_str;
+    AVFilterGraph *graph;
+    AVFilterContext **sinks;
+    int *sink_stream_map;
+    int *stream_sink_map;
+} LavfiContext;
+
+static int *create_all_formats(int n)
+{
+    int i, j, *fmts, count = 0;
+
+    for (i = 0; i < n; i++)
+        if (!(av_pix_fmt_descriptors[i].flags & PIX_FMT_HWACCEL))
+            count++;
+
+    if (!(fmts = av_malloc((count+1) * sizeof(int))))
+        return NULL;
+    for (j = 0, i = 0; i < n; i++) {
+        if (!(av_pix_fmt_descriptors[i].flags & PIX_FMT_HWACCEL))
+            fmts[j++] = i;
+    }
+    fmts[j] = -1;
+    return fmts;
+}
+
+av_cold static int lavfi_read_close(AVFormatContext *avctx)
+{
+    LavfiContext *lavfi = avctx->priv_data;
+
+    av_freep(&lavfi->sink_stream_map);
+    av_freep(&lavfi->stream_sink_map);
+    avfilter_graph_free(&lavfi->graph);
+
+    return 0;
+}
+
+av_cold static int lavfi_read_header(AVFormatContext *avctx,
+                                     AVFormatParameters *ap)
+{
+    LavfiContext *lavfi = avctx->priv_data;
+    AVFilterInOut *input_links = NULL, *output_links = NULL, *inout;
+    AVFilter *buffersink;
+    int *pix_fmts = create_all_formats(PIX_FMT_NB);
+    int ret = 0, i, n;
+
+#define FAIL(ERR) { ret = ERR; goto end; }
+
+    avfilter_register_all();
+
+    if (!(buffersink = avfilter_get_by_name("buffersink"))) {
+        av_log(avctx, AV_LOG_ERROR,
+               "Missing required buffersink filter, aborting.\n");
+        FAIL(AVERROR_FILTER_NOT_FOUND);
+    }
+
+    if (!lavfi->graph_str)
+        lavfi->graph_str = av_strdup(avctx->filename);
+
+    /* parse the graph, create a stream for each open output */
+    if (!(lavfi->graph = avfilter_graph_alloc()))
+        FAIL(AVERROR(ENOMEM));
+
+    if ((ret = avfilter_graph_parse(lavfi->graph, lavfi->graph_str,
+                                    &input_links, &output_links, avctx)) < 0)
+        FAIL(ret);
+
+    if (input_links) {
+        av_log(avctx, AV_LOG_ERROR,
+               "Open inputs in the filtergraph are not acceptable\n");
+        FAIL(AVERROR(EINVAL));
+    }
+
+    /* count the outputs */
+    for (n = 0, inout = output_links; inout; n++, inout = inout->next);
+
+    if (!(lavfi->sink_stream_map = av_malloc(sizeof(int) * n)))
+        FAIL(AVERROR(ENOMEM));
+    if (!(lavfi->stream_sink_map = av_malloc(sizeof(int) * n)))
+        FAIL(AVERROR(ENOMEM));
+
+    for (i = 0; i < n; i++)
+        lavfi->stream_sink_map[i] = -1;
+
+    /* parse the output link names - they need to be of the form out0, out1, ...
+     * create a mapping between them and the streams */
+    for (i = 0, inout = output_links; inout; i++, inout = inout->next) {
+        int stream_idx;
+        if (!strcmp(inout->name, "out"))
+            stream_idx = 0;
+        else if (sscanf(inout->name, "out%d\n", &stream_idx) != 1) {
+            av_log(avctx,  AV_LOG_ERROR,
+                   "Invalid outpad name '%s'\n", inout->name);
+            FAIL(AVERROR(EINVAL));
+        }
+
+        if ((unsigned)stream_idx >= n) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Invalid index was specified in output '%s', "
+                   "must be a non-negative value < %d\n",
+                   inout->name, n);
+            FAIL(AVERROR(EINVAL));
+        }
+
+        /* is a video output? */
+        if (inout->filter_ctx->output_pads[inout->pad_idx].type != AVMEDIA_TYPE_VIDEO) {
+            av_log(avctx,  AV_LOG_ERROR,
+                   "Output '%s' is not a video output, not yet supported", inout->name);
+            FAIL(AVERROR(EINVAL));
+        }
+
+        if (lavfi->stream_sink_map[stream_idx] != -1) {
+            av_log(avctx,  AV_LOG_ERROR,
+                   "An with stream index %d was already specified\n",
+                   stream_idx);
+            FAIL(AVERROR(EINVAL));
+        }
+        lavfi->sink_stream_map[i] = stream_idx;
+        lavfi->stream_sink_map[stream_idx] = i;
+    }
+
+    /* for each open output create a corresponding stream */
+    for (i = 0, inout = output_links; inout; i++, inout = inout->next) {
+        AVStream *st;
+        if (!(st = av_new_stream(avctx, i)))
+            FAIL(AVERROR(ENOMEM));
+    }
+
+    /* create a sink for each output and connect them to the graph */
+    lavfi->sinks = av_malloc(sizeof(AVFilterContext *) * avctx->nb_streams);
+    if (!lavfi->sinks)
+        FAIL(AVERROR(ENOMEM));
+
+    for (i = 0, inout = output_links; inout; i++, inout = inout->next) {
+        AVFilterContext *sink;
+        if ((ret = avfilter_graph_create_filter(&sink, buffersink,
+                                                inout->name, NULL,
+                                                pix_fmts, lavfi->graph)) < 0)
+            FAIL(ret);
+        lavfi->sinks[i] = sink;
+        if ((ret = avfilter_link(inout->filter_ctx, 0, sink, 0)) < 0)
+            FAIL(ret);
+    }
+
+    /* configure the graph */
+    if ((ret = avfilter_graph_config(lavfi->graph, avctx)) < 0)
+        FAIL(ret);
+
+    /* fill each stream with the information in the corresponding sink */
+    for (i = 0; i < avctx->nb_streams; i++) {
+        AVFilterLink *link = lavfi->sinks[lavfi->stream_sink_map[i]]->inputs[0];
+        AVStream *st = avctx->streams[i];
+        st->codec->codec_type = link->type;
+        av_set_pts_info(st, 64, link->time_base.num, link->time_base.den);
+        if (link->type == AVMEDIA_TYPE_VIDEO) {
+            st->codec->codec_id   = CODEC_ID_RAWVIDEO;
+            st->codec->pix_fmt    = link->format;
+            st->codec->time_base  = link->time_base;
+            st->codec->width      = link->w;
+            st->codec->height     = link->h;
+        }
+    }
+
+end:
+    avfilter_inout_free(&input_links);
+    avfilter_inout_free(&output_links);
+    if (ret < 0)
+        lavfi_read_close(avctx);
+    return ret;
+}
+
+static int lavfi_read_packet(AVFormatContext *avctx, AVPacket *pkt)
+{
+    LavfiContext *lavfi = avctx->priv_data;
+    double min_pts = DBL_MAX;
+    int min_pts_sink_idx;
+    AVFilterBufferRef *picref;
+    AVPicture pict;
+    int ret, i, size;
+
+    /* iterate through all the graph sinks. Select the sink with the
+     * minimum PTS */
+    for (i = 0; i < avctx->nb_streams; i++) {
+        AVRational tb = lavfi->sinks[i]->inputs[0]->time_base;
+        double d;
+        int ret = av_vsink_buffer_get_video_buffer_ref(lavfi->sinks[i],
+                                                       &picref, AV_VSINK_BUF_FLAG_PEEK);
+        if (ret < 0)
+            return ret;
+        d = av_rescale_q(picref->pts, tb, AV_TIME_BASE_Q);
+        if (d < min_pts) {
+            min_pts = d;
+            min_pts_sink_idx = i;
+        }
+    }
+
+    av_vsink_buffer_get_video_buffer_ref(lavfi->sinks[min_pts_sink_idx],
+                                         &picref, 0);
+
+    size = avpicture_get_size(picref->format, picref->video->w, picref->video->h);
+    if ((ret = av_new_packet(pkt, size)) < 0)
+        return ret;
+
+    memcpy(pict.data,     picref->data,     4*sizeof(picref->data[0]));
+    memcpy(pict.linesize, picref->linesize, 4*sizeof(picref->linesize[0]));
+
+    avpicture_layout(&pict, picref->format, picref->video->w,
+                     picref->video->h, pkt->data, size);
+    pkt->stream_index = lavfi->sink_stream_map[min_pts_sink_idx];
+    pkt->pts = picref->pts;
+    pkt->size = size;
+    avfilter_unref_buffer(picref);
+
+    return size;
+}
+
+#define OFFSET(x) offsetof(LavfiContext, x)
+
+#define DEC AV_OPT_FLAG_DECODING_PARAM
+
+static const AVOption options[] = {
+    { "graph", "Libavfilter graph", OFFSET(graph_str),  FF_OPT_TYPE_STRING, {.str = NULL }, 0,  0, DEC },
+    { NULL },
+};
+
+static const AVClass lavfi_class = {
+    .class_name = "lavfi indev",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+AVInputFormat ff_lavfi_demuxer = {
+    .name           = "lavfi",
+    .long_name      = NULL_IF_CONFIG_SMALL("Libavfilter virtual input device"),
+    .priv_data_size = sizeof(LavfiContext),
+    .read_header    = lavfi_read_header,
+    .read_packet    = lavfi_read_packet,
+    .read_close     = lavfi_read_close,
+    .flags          = AVFMT_NOFILE,
+    .priv_class     = &lavfi_class,
+};