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lavfi/thumbnail: support flushing.

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This makes possible the raise of one picture if the input has less than
the number of frames to analyze.

Fixes Ticket1992.
This commit is contained in:
Clément Bœsch 2013-03-13 23:59:25 +01:00
parent ed69c69a01
commit a95a38793c
2 changed files with 65 additions and 38 deletions
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2
libavfilter/version.h
View File

@ -30,7 +30,7 @@
#define LIBAVFILTER_VERSION_MAJOR 3
#define LIBAVFILTER_VERSION_MINOR 45
#define LIBAVFILTER_VERSION_MICRO 102
#define LIBAVFILTER_VERSION_MICRO 103
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
LIBAVFILTER_VERSION_MINOR, \

101
libavfilter/vf_thumbnail.c
View File

@ -41,6 +41,7 @@ typedef struct {
int n; ///< current frame
int n_frames; ///< number of frames for analysis
struct thumb_frame *frames; ///< the n_frames frames
AVRational tb; ///< copy of the input timebase to ease access
} ThumbContext;
static av_cold int init(AVFilterContext *ctx, const char *args)
@ -86,14 +87,52 @@ static double frame_sum_square_err(const int *hist, const double *median)
return sum_sq_err;
}
static AVFrame *get_best_frame(AVFilterContext *ctx)
{
AVFrame *picref;
ThumbContext *thumb = ctx->priv;
int i, j, best_frame_idx = 0;
int nb_frames = thumb->n;
double avg_hist[HIST_SIZE] = {0}, sq_err, min_sq_err = -1;
// average histogram of the N frames
for (j = 0; j < FF_ARRAY_ELEMS(avg_hist); j++) {
for (i = 0; i < nb_frames; i++)
avg_hist[j] += (double)thumb->frames[i].histogram[j];
avg_hist[j] /= nb_frames;
}
// find the frame closer to the average using the sum of squared errors
for (i = 0; i < nb_frames; i++) {
sq_err = frame_sum_square_err(thumb->frames[i].histogram, avg_hist);
if (i == 0 || sq_err < min_sq_err)
best_frame_idx = i, min_sq_err = sq_err;
}
// free and reset everything (except the best frame buffer)
for (i = 0; i < nb_frames; i++) {
memset(thumb->frames[i].histogram, 0, sizeof(thumb->frames[i].histogram));
if (i != best_frame_idx)
av_frame_unref(thumb->frames[i].buf);
}
thumb->n = 0;
// raise the chosen one
picref = thumb->frames[best_frame_idx].buf;
av_log(ctx, AV_LOG_INFO, "frame id #%d (pts_time=%f) selected "
"from a set of %d images\n", best_frame_idx,
picref->pts * av_q2d(thumb->tb), nb_frames);
thumb->frames[best_frame_idx].buf = NULL;
return picref;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
{
int i, j, best_frame_idx = 0;
double avg_hist[HIST_SIZE] = {0}, sq_err, min_sq_err = -1;
int i, j;
AVFilterContext *ctx = inlink->dst;
ThumbContext *thumb = ctx->priv;
AVFilterLink *outlink = ctx->outputs[0];
AVFrame *picref;
int *hist = thumb->frames[thumb->n].histogram;
const uint8_t *p = frame->data[0];
@ -111,40 +150,11 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
}
// no selection until the buffer of N frames is filled up
if (thumb->n < thumb->n_frames - 1) {
thumb->n++;
thumb->n++;
if (thumb->n < thumb->n_frames)
return 0;
}
// average histogram of the N frames
for (j = 0; j < FF_ARRAY_ELEMS(avg_hist); j++) {
for (i = 0; i < thumb->n_frames; i++)
avg_hist[j] += (double)thumb->frames[i].histogram[j];
avg_hist[j] /= thumb->n_frames;
}
// find the frame closer to the average using the sum of squared errors
for (i = 0; i < thumb->n_frames; i++) {
sq_err = frame_sum_square_err(thumb->frames[i].histogram, avg_hist);
if (i == 0 || sq_err < min_sq_err)
best_frame_idx = i, min_sq_err = sq_err;
}
// free and reset everything (except the best frame buffer)
for (i = 0; i < thumb->n_frames; i++) {
memset(thumb->frames[i].histogram, 0, sizeof(thumb->frames[i].histogram));
if (i == best_frame_idx)
continue;
av_frame_unref(thumb->frames[i].buf);
}
thumb->n = 0;
// raise the chosen one
picref = thumb->frames[best_frame_idx].buf;
av_log(ctx, AV_LOG_INFO, "frame id #%d (pts_time=%f) selected\n",
best_frame_idx, picref->pts * av_q2d(inlink->time_base));
thumb->frames[best_frame_idx].buf = NULL;
return ff_filter_frame(outlink, picref);
return ff_filter_frame(outlink, get_best_frame(ctx));
}
static av_cold void uninit(AVFilterContext *ctx)
@ -158,18 +168,34 @@ static av_cold void uninit(AVFilterContext *ctx)
static int request_frame(AVFilterLink *link)
{
ThumbContext *thumb = link->src->priv;
AVFilterContext *ctx = link->src;
ThumbContext *thumb = ctx->priv;
/* loop until a frame thumbnail is available (when a frame is queued,
* thumb->n is reset to zero) */
do {
int ret = ff_request_frame(link->src->inputs[0]);
int ret = ff_request_frame(ctx->inputs[0]);
if (ret == AVERROR_EOF && thumb->n) {
ret = ff_filter_frame(link, get_best_frame(ctx));
if (ret < 0)
return ret;
ret = AVERROR_EOF;
}
if (ret < 0)
return ret;
} while (thumb->n);
return 0;
}
static int config_props(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
ThumbContext *thumb = ctx->priv;
thumb->tb = inlink->time_base;
return 0;
}
static int query_formats(AVFilterContext *ctx)
{
static const enum AVPixelFormat pix_fmts[] = {
@ -184,6 +210,7 @@ static const AVFilterPad thumbnail_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_props,
.get_video_buffer = ff_null_get_video_buffer,
.filter_frame = filter_frame,
},