FFmpeg/libavfilter/avfiltergraph.c

/*
 * filter graphs
 * copyright (c) 2007 Bobby Bingham
 *
 * 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
 */

#include "avfilter.h"
#include "avfiltergraph.h"

typedef struct AVFilterGraph {
    unsigned filter_count;
    AVFilterContext **filters;

    /** fake filters to handle links to internal filters */
    AVFilterContext *link_filter_in;
    AVFilterContext *link_filter_out;
} GraphContext;

typedef struct {
    AVFilterContext *graph;
} GraphLinkContext;

static int link_init(AVFilterContext *ctx, const char *args, void *opaque)
{
    GraphLinkContext *linkctx = ctx->priv;
    linkctx->graph = opaque;
    return !opaque;
}

/**
 * Given the link between the dummy filter and an internal filter whose input
 * is being exported outside the graph, this returns the externally visible
 * link.
 */
static inline AVFilterLink *get_extern_input_link(AVFilterLink *link)
{
    GraphLinkContext *lctx = link->src->priv;
    return lctx->graph->inputs[link->srcpad];
}

/**
 * Given the link between the dummy filter and an internal filter whose output
 * is being exported outside the graph, this returns the externally visible
 * link.
 */
static inline AVFilterLink *get_extern_output_link(AVFilterLink *link)
{
    GraphLinkContext *lctx = link->dst->priv;
    return lctx->graph->outputs[link->dstpad];
}


/** dummy filter used to help export filters pads outside the graph */
static AVFilter vf_graph_dummy =
{
    .name      = "graph_dummy",

    .priv_size = sizeof(GraphLinkContext),

    .init      = link_init,

    .inputs    = (AVFilterPad[]) {{ .name = NULL, }},
    .outputs   = (AVFilterPad[]) {{ .name = NULL, }},
};

static void uninit(AVFilterContext *ctx)
{
    GraphContext *graph = ctx->priv;

    if(graph->link_filter_in) {
        avfilter_destroy(graph->link_filter_in);
        graph->link_filter_in = NULL;
    }
    if(graph->link_filter_out) {
        avfilter_destroy(graph->link_filter_out);
        graph->link_filter_out = NULL;
    }
    for(; graph->filter_count > 0; graph->filter_count --)
        avfilter_destroy(graph->filters[graph->filter_count - 1]);
    av_freep(&graph->filters);
}

/* TODO: insert in sorted order */
void avfilter_graph_add_filter(AVFilterContext *graphctx, AVFilterContext *filter)
{
    GraphContext *graph = graphctx->priv;

    graph->filters = av_realloc(graph->filters,
                                sizeof(AVFilterContext*) * ++graph->filter_count);
    graph->filters[graph->filter_count - 1] = filter;
}

/* search intelligently, once we insert in order */
AVFilterContext *avfilter_graph_get_filter(AVFilterContext *ctx, char *name)
{
    GraphContext *graph = ctx->priv;
    int i;

    if(!name)
        return NULL;

    for(i = 0; i < graph->filter_count; i ++)
        if(graph->filters[i]->name && !strcmp(name, graph->filters[i]->name))
            return graph->filters[i];

    return NULL;
}

static int query_formats(AVFilterContext *graphctx)
{
    GraphContext *graph = graphctx->priv;
    AVFilterContext *linkfiltin  = graph->link_filter_in;
    AVFilterContext *linkfiltout = graph->link_filter_out;
    int i, j;

    /* ask all the sub-filters for their supported colorspaces */
    for(i = 0; i < graph->filter_count; i ++) {
        if(graph->filters[i]->filter->query_formats)
            graph->filters[i]->filter->query_formats(graph->filters[i]);
        else
            avfilter_default_query_formats(graph->filters[i]);
    }

    /* use these formats on our exported links */
    for(i = 0; i < linkfiltout->input_count; i ++) {
        avfilter_formats_ref( linkfiltout->inputs[i]->in_formats,
                             &linkfiltout->inputs[i]->out_formats);

        if(graphctx->outputs[i])
            avfilter_formats_ref(linkfiltout->inputs[i]->in_formats,
                                 &graphctx->outputs[i]->in_formats);
    }
    for(i = 0; i < linkfiltin->output_count; i ++) {
        avfilter_formats_ref( linkfiltin->outputs[i]->out_formats,
                             &linkfiltin->outputs[i]->in_formats);

        if(graphctx->inputs[i])
            avfilter_formats_ref(linkfiltin->outputs[i]->out_formats,
                                 &graphctx-> inputs[i]->out_formats);
    }

    /* go through and merge as many format lists as possible */
    for(i = 0; i < graph->filter_count; i ++) {
        AVFilterContext *filter = graph->filters[i];

        for(j = 0; j < filter->input_count; j ++) {
            AVFilterLink *link;
            if(!(link = filter->inputs[j]))
                continue;
            if(link->in_formats != link->out_formats) {
                if(!avfilter_merge_formats(link->in_formats,
                                           link->out_formats)) {
                    /* couldn't merge format lists. auto-insert scale filter */
                    AVFilterContext *scale;

                    if(!(scale =
                         avfilter_open(avfilter_get_by_name("scale"), NULL)))
                        return -1;
                    if(scale->filter->init(scale, NULL, NULL) ||
                       avfilter_insert_filter(link, scale, 0, 0)) {
                        avfilter_destroy(scale);
                        return -1;
                    }

                    avfilter_graph_add_filter(graphctx, scale);
                    scale->filter->query_formats(scale);
                    if(!avfilter_merge_formats(scale-> inputs[0]->in_formats,
                                              scale-> inputs[0]->out_formats) ||
                       !avfilter_merge_formats(scale->outputs[0]->in_formats,
                                              scale->outputs[0]->out_formats))
                        return -1;
                }
            }
        }
    }

    return 0;
}

static void pick_format(AVFilterLink *link)
{
    if(!link || !link->in_formats)
        return;

    link->in_formats->format_count = 1;
    link->format = link->in_formats->formats[0];

    avfilter_formats_unref(&link->in_formats);
    avfilter_formats_unref(&link->out_formats);
}

static void pick_formats(GraphContext *graph)
{
    int i, j;

    for(i = 0; i < graph->filter_count; i ++) {
        AVFilterContext *filter = graph->filters[i];

        if(filter->filter == &avfilter_vf_graph)
            pick_formats(filter->priv);

        for(j = 0; j < filter->input_count; j ++)
            pick_format(filter->inputs[j]);
        for(j = 0; j < filter->output_count; j ++)
            pick_format(filter->outputs[j]);
    }
}

int avfilter_graph_config_formats(AVFilterContext *graphctx)
{
    GraphContext *graph = graphctx->priv;

    /* find supported formats from sub-filters, and merge along links */
    if(query_formats(graphctx))
        return -1;

    /* Once everything is merged, it's possible that we'll still have
     * multiple valid colorspace choices. We pick the first one. */
    pick_formats(graph);

    return 0;
}

static int graph_load_from_desc2(AVFilterContext *ctx, AVFilterGraphDesc *desc)
{
    AVFilterGraphDescFilter *curfilt;
    AVFilterGraphDescLink   *curlink;
    AVFilterContext *filt, *filtb;

    AVFilter *filterdef;
    char tmp[20];

    /* create all filters */
    for(curfilt = desc->filters; curfilt; curfilt = curfilt->next) {
        snprintf(tmp, 20, "%d", curfilt->index);
        if(!(filterdef = avfilter_get_by_name(curfilt->filter)) ||
           !(filt = avfilter_open(filterdef, tmp))) {
            av_log(ctx, AV_LOG_ERROR,
               "error creating filter '%s'\n", curfilt->filter);
            goto fail;
        }
        avfilter_graph_add_filter(ctx, filt);
        if(avfilter_init_filter(filt, curfilt->args, NULL)) {
            av_log(ctx, AV_LOG_ERROR,
                "error initializing filter '%s'\n", curfilt->filter);
            goto fail;
        }
    }

    /* create all links */
    for(curlink = desc->links; curlink; curlink = curlink->next) {
        snprintf(tmp, 20, "%d", curlink->src);
        if(!(filt = avfilter_graph_get_filter(ctx, tmp))) {
            av_log(ctx, AV_LOG_ERROR, "link source does not exist in graph\n");
            goto fail;
        }
        snprintf(tmp, 20, "%d", curlink->dst);
        if(!(filtb = avfilter_graph_get_filter(ctx, tmp))) {
            av_log(ctx, AV_LOG_ERROR, "link destination does not exist in graph\n");
            goto fail;
        }
        if(avfilter_link(filt, curlink->srcpad, filtb, curlink->dstpad)) {
            av_log(ctx, AV_LOG_ERROR, "cannot create link between source and destination filters\n");
            goto fail;
        }
    }

    return 0;

fail:
    uninit(ctx);
    return -1;
}

int graph_load_from_desc3(AVFilterContext *ctx, AVFilterGraphDesc *desc, AVFilterContext *in, int inpad, AVFilterContext *out, int outpad)
{
    AVFilterGraphDescExport *curpad;
    char tmp[20];
    AVFilterContext *filt;

    if (graph_load_from_desc2(ctx, desc) < 0)
        goto fail;

    /* export all input pads */
    for(curpad = desc->inputs; curpad; curpad = curpad->next) {
        snprintf(tmp, 20, "%d", curpad->filter);
        if(!(filt = avfilter_graph_get_filter(ctx, tmp))) {
            av_log(ctx, AV_LOG_ERROR, "filter owning exported pad does not exist\n");
            goto fail;
        }
        if(avfilter_link(in, inpad, filt, curpad->pad)) {
            av_log(ctx, AV_LOG_ERROR, "cannot create link between source and destination filters\n");
            goto fail;
        }
    }

    /* export all output pads */
    for(curpad = desc->outputs; curpad; curpad = curpad->next) {
        snprintf(tmp, 20, "%d", curpad->filter);
        if(!(filt = avfilter_graph_get_filter(ctx, tmp))) {
            av_log(ctx, AV_LOG_ERROR, "filter owning exported pad does not exist\n");
            goto fail;
        }

        if(avfilter_link(filt, curpad->pad, out, outpad)) {
            av_log(ctx, AV_LOG_ERROR, "cannot create link between source and destination filters\n");
            goto fail;
        }
    }

    return 0;

fail:
    uninit(ctx);
    return -1;
}

static int init(AVFilterContext *ctx, const char *args, void *opaque)
{
    GraphContext *gctx = ctx->priv;

    if(!(gctx->link_filter_in = avfilter_open(&vf_graph_dummy, NULL)))
        return -1;
    if(avfilter_init_filter(gctx->link_filter_in, NULL, ctx))
        goto fail;
    if(!(gctx->link_filter_out = avfilter_open(&vf_graph_dummy, NULL)))
        goto fail;
    if(avfilter_init_filter(gctx->link_filter_out, NULL, ctx))
        goto fail;

    return 0;

fail:
    avfilter_destroy(gctx->link_filter_in);
    if(gctx->link_filter_out)
        avfilter_destroy(gctx->link_filter_out);
    return -1;
}

AVFilter avfilter_vf_graph =
{
    .name      = "graph",

    .priv_size = sizeof(GraphContext),

    .init      = init,
    .uninit    = uninit,

    .query_formats = query_formats,

    .inputs    = (AVFilterPad[]) {{ .name = NULL, }},
    .outputs   = (AVFilterPad[]) {{ .name = NULL, }},
};