libavfilter/vf_fps.c - third_party/ffmpeg - Git at Google

 /*
  * Copyright 2007 Bobby Bingham
  * Copyright 2012 Robert Nagy <ronag89 gmail com>
  * Copyright 2012 Anton Khirnov <anton khirnov net>
  *
  * 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
  * a filter enforcing given constant framerate
  */

 #include "libavutil/fifo.h"
 #include "libavutil/mathematics.h"
 #include "libavutil/opt.h"
 #include "libavutil/parseutils.h"

 #include "avfilter.h"

 typedef struct FPSContext {
     const AVClass *class;

     AVFifoBuffer *fifo;     ///< store frames until we get two successive timestamps

     /* timestamps in input timebase */
     int64_t first_pts;      ///< pts of the first frame that arrived on this filter
     int64_t pts;            ///< pts of the first frame currently in the fifo

     AVRational framerate;   ///< target framerate
     char *fps;              ///< a string describing target framerate

     /* statistics */
     int frames_in;             ///< number of frames on input
     int frames_out;            ///< number of frames on output
     int dup;                   ///< number of frames duplicated
     int drop;                  ///< number of framed dropped
 } FPSContext;

 #define OFFSET(x) offsetof(FPSContext, x)
 #define V AV_OPT_FLAG_VIDEO_PARAM
 static const AVOption options[] = {
     { "fps", "A string describing desired output framerate", OFFSET(fps), AV_OPT_TYPE_STRING, { .str = "25" }, .flags = V },
     { NULL },
 };

 static const AVClass class = {
     .class_name = "FPS filter",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };

 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
 {
     FPSContext *s = ctx->priv;
     int ret;

     s->class = &class;
     av_opt_set_defaults(s);

     if ((ret = av_set_options_string(s, args, "=", ":")) < 0) {
         av_log(ctx, AV_LOG_ERROR, "Error parsing the options string %s.\n",
                args);
         return ret;
     }

     if ((ret = av_parse_video_rate(&s->framerate, s->fps)) < 0) {
         av_log(ctx, AV_LOG_ERROR, "Error parsing framerate %s.\n", s->fps);
         return ret;
     }
     av_opt_free(s);

     if (!(s->fifo = av_fifo_alloc(2*sizeof(AVFilterBufferRef*))))
         return AVERROR(ENOMEM);

     av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", s->framerate.num, s->framerate.den);
     return 0;
 }

 static void flush_fifo(AVFifoBuffer *fifo)
 {
     while (av_fifo_size(fifo)) {
         AVFilterBufferRef *tmp;
         av_fifo_generic_read(fifo, &tmp, sizeof(tmp), NULL);
         avfilter_unref_buffer(tmp);
     }
 }

 static av_cold void uninit(AVFilterContext *ctx)
 {
     FPSContext *s = ctx->priv;
     if (s->fifo) {
         flush_fifo(s->fifo);
         av_fifo_free(s->fifo);
     }

     av_log(ctx, AV_LOG_VERBOSE, "%d frames in, %d frames out; %d frames dropped, "
            "%d frames duplicated.\n", s->frames_in, s->frames_out, s->drop, s->dup);
 }

 static int config_props(AVFilterLink* link)
 {
     FPSContext   *s = link->src->priv;

     link->time_base = (AVRational){ s->framerate.den, s->framerate.num };
     link->w         = link->src->inputs[0]->w;
     link->h         = link->src->inputs[0]->h;
     s->pts          = AV_NOPTS_VALUE;

     return 0;
 }

 static int request_frame(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     FPSContext        *s = ctx->priv;
     int frames_out = s->frames_out;
     int ret = 0;

     while (ret >= 0 && s->frames_out == frames_out)
         ret = avfilter_request_frame(ctx->inputs[0]);

     /* flush the fifo */
     if (ret == AVERROR_EOF && av_fifo_size(s->fifo)) {
         int i;
         for (i = 0; av_fifo_size(s->fifo); i++) {
             AVFilterBufferRef *buf;

             av_fifo_generic_read(s->fifo, &buf, sizeof(buf), NULL);
             buf->pts = av_rescale_q(s->first_pts, ctx->inputs[0]->time_base,
                                     outlink->time_base) + s->frames_out;

             avfilter_start_frame(outlink, buf);
             avfilter_draw_slice(outlink, 0, outlink->h, 1);
             avfilter_end_frame(outlink);
             s->frames_out++;
         }
         return 0;
     }

     return ret;
 }

 static int write_to_fifo(AVFifoBuffer *fifo, AVFilterBufferRef *buf)
 {
     int ret;

     if (!av_fifo_space(fifo) &&
         (ret = av_fifo_realloc2(fifo, 2*av_fifo_size(fifo))))
         return ret;

     av_fifo_generic_write(fifo, &buf, sizeof(buf), NULL);
     return 0;
 }

 static void end_frame(AVFilterLink *inlink)
 {
     AVFilterContext    *ctx = inlink->dst;
     FPSContext           *s = ctx->priv;
     AVFilterLink   *outlink = ctx->outputs[0];
     AVFilterBufferRef  *buf = inlink->cur_buf;
     int64_t delta;
     int i;

     s->frames_in++;
     /* discard frames until we get the first timestamp */
     if (s->pts == AV_NOPTS_VALUE) {
         if (buf->pts != AV_NOPTS_VALUE) {
             write_to_fifo(s->fifo, buf);
             s->first_pts = s->pts = buf->pts;
         } else {
             av_log(ctx, AV_LOG_WARNING, "Discarding initial frame(s) with no "
                    "timestamp.\n");
             avfilter_unref_buffer(buf);
             s->drop++;
         }
         return;
     }

     /* now wait for the next timestamp */
     if (buf->pts == AV_NOPTS_VALUE || av_fifo_size(s->fifo) <= 0) {
         write_to_fifo(s->fifo, buf);
         return;
     }

     /* number of output frames */
     delta = av_rescale_q(buf->pts - s->pts, inlink->time_base,
                          outlink->time_base);

     if (delta < 1) {
         /* drop the frame and everything buffered except the first */
         AVFilterBufferRef *tmp;
         int drop = av_fifo_size(s->fifo)/sizeof(AVFilterBufferRef*);

         av_log(ctx, AV_LOG_DEBUG, "Dropping %d frame(s).\n", drop);
         s->drop += drop;

         av_fifo_generic_read(s->fifo, &tmp, sizeof(tmp), NULL);
         flush_fifo(s->fifo);
         write_to_fifo(s->fifo, tmp);

         avfilter_unref_buffer(buf);
         return;
     }

     /* can output >= 1 frames */
     for (i = 0; i < delta; i++) {
         AVFilterBufferRef *buf_out;
         av_fifo_generic_read(s->fifo, &buf_out, sizeof(buf_out), NULL);

         /* duplicate the frame if needed */
         if (!av_fifo_size(s->fifo) && i < delta - 1) {
             av_log(ctx, AV_LOG_DEBUG, "Duplicating frame.\n");
             write_to_fifo(s->fifo, avfilter_ref_buffer(buf_out, AV_PERM_READ));
             s->dup++;
         }

         buf_out->pts = av_rescale_q(s->first_pts, inlink->time_base,
                                     outlink->time_base) + s->frames_out;

         avfilter_start_frame(outlink, buf_out);
         avfilter_draw_slice(outlink, 0, outlink->h, 1);
         avfilter_end_frame(outlink);
         s->frames_out++;
     }
     flush_fifo(s->fifo);

     write_to_fifo(s->fifo, buf);
     s->pts = s->first_pts + av_rescale_q(s->frames_out, outlink->time_base, inlink->time_base);
 }

 static void null_start_frame(AVFilterLink *link, AVFilterBufferRef *buf)
 {
 }

 static void null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
 {
 }

 AVFilter avfilter_vf_fps = {
     .name        = "fps",
     .description = NULL_IF_CONFIG_SMALL("Force constant framerate"),

     .init      = init,
     .uninit    = uninit,

     .priv_size = sizeof(FPSContext),

     .inputs    = (AVFilterPad[]) {{ .name            = "default",
                                     .type            = AVMEDIA_TYPE_VIDEO,
                                     .start_frame     = null_start_frame,
                                     .draw_slice      = null_draw_slice,
                                     .end_frame       = end_frame, },
                                   { .name = NULL}},
     .outputs   = (AVFilterPad[]) {{ .name            = "default",
                                     .type            = AVMEDIA_TYPE_VIDEO,
                                     .request_frame   = request_frame,
                                     .config_props    = config_props},
                                   { .name = NULL}},
 };
	/*
	* Copyright 2007 Bobby Bingham
	* Copyright 2012 Robert Nagy <ronag89 gmail com>
	* Copyright 2012 Anton Khirnov <anton khirnov net>
	*
	* 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
	* a filter enforcing given constant framerate
	*/

	#include "libavutil/fifo.h"
	#include "libavutil/mathematics.h"
	#include "libavutil/opt.h"
	#include "libavutil/parseutils.h"

	#include "avfilter.h"

	typedef struct FPSContext {
	const AVClass *class;

	AVFifoBuffer *fifo; ///< store frames until we get two successive timestamps

	/* timestamps in input timebase */
	int64_t first_pts; ///< pts of the first frame that arrived on this filter
	int64_t pts; ///< pts of the first frame currently in the fifo

	AVRational framerate; ///< target framerate
	char *fps; ///< a string describing target framerate

	/* statistics */
	int frames_in; ///< number of frames on input
	int frames_out; ///< number of frames on output
	int dup; ///< number of frames duplicated
	int drop; ///< number of framed dropped
	} FPSContext;

	#define OFFSET(x) offsetof(FPSContext, x)
	#define V AV_OPT_FLAG_VIDEO_PARAM
	static const AVOption options[] = {
	{ "fps", "A string describing desired output framerate", OFFSET(fps), AV_OPT_TYPE_STRING, { .str = "25" }, .flags = V },
	{ NULL },
	};

	static const AVClass class = {
	.class_name = "FPS filter",
	.item_name = av_default_item_name,
	.option = options,
	.version = LIBAVUTIL_VERSION_INT,
	};

	static av_cold int init(AVFilterContext ctx, const char args, void *opaque)
	{
	FPSContext *s = ctx->priv;
	int ret;

	s->class = &class;
	av_opt_set_defaults(s);

	if ((ret = av_set_options_string(s, args, "=", ":")) < 0) {
	av_log(ctx, AV_LOG_ERROR, "Error parsing the options string %s.\n",
	args);
	return ret;
	}

	if ((ret = av_parse_video_rate(&s->framerate, s->fps)) < 0) {
	av_log(ctx, AV_LOG_ERROR, "Error parsing framerate %s.\n", s->fps);
	return ret;
	}
	av_opt_free(s);

	if (!(s->fifo = av_fifo_alloc(2sizeof(AVFilterBufferRef))))
	return AVERROR(ENOMEM);

	av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", s->framerate.num, s->framerate.den);
	return 0;
	}

	static void flush_fifo(AVFifoBuffer *fifo)
	{
	while (av_fifo_size(fifo)) {
	AVFilterBufferRef *tmp;
	av_fifo_generic_read(fifo, &tmp, sizeof(tmp), NULL);
	avfilter_unref_buffer(tmp);
	}
	}

	static av_cold void uninit(AVFilterContext *ctx)
	{
	FPSContext *s = ctx->priv;
	if (s->fifo) {
	flush_fifo(s->fifo);
	av_fifo_free(s->fifo);
	}

	av_log(ctx, AV_LOG_VERBOSE, "%d frames in, %d frames out; %d frames dropped, "
	"%d frames duplicated.\n", s->frames_in, s->frames_out, s->drop, s->dup);
	}

	static int config_props(AVFilterLink* link)
	{
	FPSContext *s = link->src->priv;

	link->time_base = (AVRational){ s->framerate.den, s->framerate.num };
	link->w = link->src->inputs[0]->w;
	link->h = link->src->inputs[0]->h;
	s->pts = AV_NOPTS_VALUE;

	return 0;
	}

	static int request_frame(AVFilterLink *outlink)
	{
	AVFilterContext *ctx = outlink->src;
	FPSContext *s = ctx->priv;
	int frames_out = s->frames_out;
	int ret = 0;

	while (ret >= 0 && s->frames_out == frames_out)
	ret = avfilter_request_frame(ctx->inputs[0]);

	/* flush the fifo */
	if (ret == AVERROR_EOF && av_fifo_size(s->fifo)) {
	int i;
	for (i = 0; av_fifo_size(s->fifo); i++) {
	AVFilterBufferRef *buf;

	av_fifo_generic_read(s->fifo, &buf, sizeof(buf), NULL);
	buf->pts = av_rescale_q(s->first_pts, ctx->inputs[0]->time_base,
	outlink->time_base) + s->frames_out;

	avfilter_start_frame(outlink, buf);
	avfilter_draw_slice(outlink, 0, outlink->h, 1);
	avfilter_end_frame(outlink);
	s->frames_out++;
	}
	return 0;
	}

	return ret;
	}

	static int write_to_fifo(AVFifoBuffer fifo, AVFilterBufferRef buf)
	{
	int ret;

	if (!av_fifo_space(fifo) &&
	(ret = av_fifo_realloc2(fifo, 2*av_fifo_size(fifo))))
	return ret;

	av_fifo_generic_write(fifo, &buf, sizeof(buf), NULL);
	return 0;
	}

	static void end_frame(AVFilterLink *inlink)
	{
	AVFilterContext *ctx = inlink->dst;
	FPSContext *s = ctx->priv;
	AVFilterLink *outlink = ctx->outputs[0];
	AVFilterBufferRef *buf = inlink->cur_buf;
	int64_t delta;
	int i;

	s->frames_in++;
	/* discard frames until we get the first timestamp */
	if (s->pts == AV_NOPTS_VALUE) {
	if (buf->pts != AV_NOPTS_VALUE) {
	write_to_fifo(s->fifo, buf);
	s->first_pts = s->pts = buf->pts;
	} else {
	av_log(ctx, AV_LOG_WARNING, "Discarding initial frame(s) with no "
	"timestamp.\n");
	avfilter_unref_buffer(buf);
	s->drop++;
	}
	return;
	}

	/* now wait for the next timestamp */
	if (buf->pts == AV_NOPTS_VALUE \|\| av_fifo_size(s->fifo) <= 0) {
	write_to_fifo(s->fifo, buf);
	return;
	}

	/* number of output frames */
	delta = av_rescale_q(buf->pts - s->pts, inlink->time_base,
	outlink->time_base);

	if (delta < 1) {
	/* drop the frame and everything buffered except the first */
	AVFilterBufferRef *tmp;
	int drop = av_fifo_size(s->fifo)/sizeof(AVFilterBufferRef*);

	av_log(ctx, AV_LOG_DEBUG, "Dropping %d frame(s).\n", drop);
	s->drop += drop;

	av_fifo_generic_read(s->fifo, &tmp, sizeof(tmp), NULL);
	flush_fifo(s->fifo);
	write_to_fifo(s->fifo, tmp);

	avfilter_unref_buffer(buf);
	return;
	}

	/* can output >= 1 frames */
	for (i = 0; i < delta; i++) {
	AVFilterBufferRef *buf_out;
	av_fifo_generic_read(s->fifo, &buf_out, sizeof(buf_out), NULL);

	/* duplicate the frame if needed */
	if (!av_fifo_size(s->fifo) && i < delta - 1) {
	av_log(ctx, AV_LOG_DEBUG, "Duplicating frame.\n");
	write_to_fifo(s->fifo, avfilter_ref_buffer(buf_out, AV_PERM_READ));
	s->dup++;
	}

	buf_out->pts = av_rescale_q(s->first_pts, inlink->time_base,
	outlink->time_base) + s->frames_out;

	avfilter_start_frame(outlink, buf_out);
	avfilter_draw_slice(outlink, 0, outlink->h, 1);
	avfilter_end_frame(outlink);
	s->frames_out++;
	}
	flush_fifo(s->fifo);

	write_to_fifo(s->fifo, buf);
	s->pts = s->first_pts + av_rescale_q(s->frames_out, outlink->time_base, inlink->time_base);
	}

	static void null_start_frame(AVFilterLink link, AVFilterBufferRef buf)
	{
	}

	static void null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
	{
	}

	AVFilter avfilter_vf_fps = {
	.name = "fps",
	.description = NULL_IF_CONFIG_SMALL("Force constant framerate"),

	.init = init,
	.uninit = uninit,

	.priv_size = sizeof(FPSContext),

	.inputs = (AVFilterPad[]) {{ .name = "default",
	.type = AVMEDIA_TYPE_VIDEO,
	.start_frame = null_start_frame,
	.draw_slice = null_draw_slice,
	.end_frame = end_frame, },
	{ .name = NULL}},
	.outputs = (AVFilterPad[]) {{ .name = "default",
	.type = AVMEDIA_TYPE_VIDEO,
	.request_frame = request_frame,
	.config_props = config_props},
	{ .name = NULL}},
	};