[FFmpeg-devel] [PATCH 3/3] lavfi: support multiple rounds of format negotiation.
Nicolas George
nicolas.george at normalesup.org
Thu Feb 21 20:44:15 CET 2013
Remove the temporary hack for amerge and replace it with a
generic solution.
Signed-off-by: Nicolas George <nicolas.george at normalesup.org>
---
doc/filter_design.txt | 5 +++
libavfilter/avfiltergraph.c | 103 ++++++++++++++++++++++++++++++++-----------
2 files changed, 83 insertions(+), 25 deletions(-)
The logic is this: the query_formats() function will fail with
AVERROR(EINVAL) if some filters could not be configured yet but progress was
made, and the calling site will loop on that condition. It is as simple as
that, all the noise in the diff is mostly connected to making sure that
filters are not configured twice (most of them would cause crashes).
I believe that with this feature, overlay can peek at its inputs supported
formats (and possibly output too) and decide automatically between the
yuv420/yuv444/rgb mode.
Note that that feature must be used parsimoniously, because the mode filters
use it, the more likely it is that the process will fail because of a
circular dependency.
diff --git a/doc/filter_design.txt b/doc/filter_design.txt
index 772ca9d..2f9e57d 100644
--- a/doc/filter_design.txt
+++ b/doc/filter_design.txt
@@ -29,6 +29,11 @@ Format negotiation
same format amongst a supported list, all it has to do is use a reference
to the same list of formats.
+ query_formats can leave some formats unset and return AVERROR(EAGAIN) to
+ cause the negotiation mechanism to try again later. That can be used by
+ filters with complex requirements to use the format negotiated on one link
+ to set the formats supported on another.
+
Buffer references ownership and permissions
===========================================
diff --git a/libavfilter/avfiltergraph.c b/libavfilter/avfiltergraph.c
index 0bc8464..600255c 100644
--- a/libavfilter/avfiltergraph.c
+++ b/libavfilter/avfiltergraph.c
@@ -24,6 +24,7 @@
#include <string.h>
#include "libavutil/avassert.h"
+#include "libavutil/bprint.h"
#include "libavutil/channel_layout.h"
#include "libavutil/opt.h"
#include "libavutil/pixdesc.h"
@@ -211,8 +212,9 @@ static int filter_query_formats(AVFilterContext *ctx)
AVMEDIA_TYPE_VIDEO;
if ((ret = ctx->filter->query_formats(ctx)) < 0) {
- av_log(ctx, AV_LOG_ERROR, "Query format failed for '%s': %s\n",
- ctx->name, av_err2str(ret));
+ if (ret != AVERROR(EAGAIN))
+ av_log(ctx, AV_LOG_ERROR, "Query format failed for '%s': %s\n",
+ ctx->name, av_err2str(ret));
return ret;
}
@@ -238,27 +240,46 @@ static int filter_query_formats(AVFilterContext *ctx)
return 0;
}
+static int formats_queried(AVFilterContext *f)
+{
+ int i;
+
+ for (i = 0; i < f->nb_inputs; i++) {
+ if (!f->inputs[i]->out_formats)
+ return 0;
+ if (f->inputs[i]->type == AVMEDIA_TYPE_AUDIO &&
+ !(f->inputs[i]->out_samplerates &&
+ f->inputs[i]->out_channel_layouts))
+ return 0;
+ }
+ for (i = 0; i < f->nb_outputs; i++) {
+ if (!f->outputs[i]->in_formats)
+ return 0;
+ if (f->outputs[i]->type == AVMEDIA_TYPE_AUDIO &&
+ !(f->outputs[i]->in_samplerates &&
+ f->outputs[i]->in_channel_layouts))
+ return 0;
+ }
+ return 1;
+}
+
static int query_formats(AVFilterGraph *graph, AVClass *log_ctx)
{
int i, j, ret;
int scaler_count = 0, resampler_count = 0;
+ int merge_done = 0, merge_already = 0, merge_delayed = 0;
- for (j = 0; j < 2; j++) {
- /* ask all the sub-filters for their supported media formats */
for (i = 0; i < graph->filter_count; i++) {
- /* Call query_formats on sources first.
- This is a temporary workaround for amerge,
- until format renegociation is implemented. */
- if (!graph->filters[i]->nb_inputs == j)
+ AVFilterContext *f = graph->filters[i];
+ if (formats_queried(f))
continue;
- if (graph->filters[i]->filter->query_formats)
- ret = filter_query_formats(graph->filters[i]);
+ if (f->filter->query_formats)
+ ret = filter_query_formats(f);
else
- ret = ff_default_query_formats(graph->filters[i]);
- if (ret < 0)
+ ret = ff_default_query_formats(f);
+ if (ret < 0 && ret != AVERROR(EAGAIN))
return ret;
}
- }
/* go through and merge as many format lists as possible */
for (i = 0; i < graph->filter_count; i++) {
@@ -271,20 +292,32 @@ static int query_formats(AVFilterGraph *graph, AVClass *log_ctx)
if (!link)
continue;
- if (link->in_formats != link->out_formats &&
- !ff_merge_formats(link->in_formats,
- link->out_formats))
- convert_needed = 1;
+#define MERGE_DISPATCH(field, statement) \
+ if (!(link->in_ ## field && link->out_ ## field)) { \
+ merge_delayed++; \
+ } else if (link->in_ ## field == link->out_ ## field) { \
+ merge_already++; \
+ } else { \
+ merge_done++; \
+ statement \
+ }
+ MERGE_DISPATCH(formats,
+ if (!ff_merge_formats(link->in_formats, link->out_formats))
+ convert_needed = 1;
+ )
if (link->type == AVMEDIA_TYPE_AUDIO) {
- if (link->in_channel_layouts != link->out_channel_layouts &&
- !ff_merge_channel_layouts(link->in_channel_layouts,
+ MERGE_DISPATCH(channel_layouts,
+ if (!ff_merge_channel_layouts(link->in_channel_layouts,
link->out_channel_layouts))
- convert_needed = 1;
- if (link->in_samplerates != link->out_samplerates &&
- !ff_merge_samplerates(link->in_samplerates,
- link->out_samplerates))
- convert_needed = 1;
+ convert_needed = 1;
+ )
+ MERGE_DISPATCH(samplerates,
+ if (!ff_merge_samplerates(link->in_samplerates,
+ link->out_samplerates))
+ convert_needed = 1;
+ )
}
+#undef MERGE_DISPATCH
if (convert_needed) {
AVFilterContext *convert;
@@ -363,6 +396,24 @@ static int query_formats(AVFilterGraph *graph, AVClass *log_ctx)
}
}
+ av_log(graph, AV_LOG_DEBUG,
+ "query_formats: %d done, %d already, %d delayed\n",
+ merge_done, merge_already, merge_delayed);
+ if (merge_delayed) {
+ AVBPrint bp;
+
+ if (merge_done)
+ return AVERROR(EAGAIN);
+ av_bprint_init(&bp, 0, AV_BPRINT_SIZE_AUTOMATIC);
+ for (i = 0; i < graph->filter_count; i++)
+ if (!formats_queried(graph->filters[i]))
+ av_bprintf(&bp, "%s%s", bp.len ? ", " : "",
+ graph->filters[i]->name);
+ av_log(graph, AV_LOG_ERROR,
+ "The following filters could not choose their formats: %s\n"
+ "Consider inserting the (a)format filter.\n", bp.str);
+ return AVERROR(EIO);
+ }
return 0;
}
@@ -826,7 +877,9 @@ static int graph_config_formats(AVFilterGraph *graph, AVClass *log_ctx)
int ret;
/* find supported formats from sub-filters, and merge along links */
- if ((ret = query_formats(graph, log_ctx)) < 0)
+ while ((ret = query_formats(graph, log_ctx)) == AVERROR(EAGAIN))
+ av_log(graph, AV_LOG_DEBUG, "query_formats not finished\n");
+ if (ret < 0)
return ret;
/* Once everything is merged, it's possible that we'll still have
--
1.7.10.4
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