obs-studio/libobs/media-io/video-io.c

/******************************************************************************
    Copyright (C) 2013 by Hugh Bailey <[email protected]>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 2 of the License, or
    (at your option) any later version.

    This program 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
******************************************************************************/

#include <assert.h>
#include "../util/bmem.h"
#include "../util/platform.h"
#include "../util/threading.h"

#include "video-io.h"

struct video_output {
	struct video_info  info;
	media_t            media;
	media_output_t     output;

	pthread_t          thread;
	pthread_mutex_t    data_mutex;
	event_t            stop_event;

	struct video_frame *cur_frame;
	struct video_frame *next_frame;
	event_t            update_event;
	uint64_t           frame_time;
	volatile uint64_t  cur_video_time;

	bool               initialized;
};

/* ------------------------------------------------------------------------- */

static inline void video_swapframes(struct video_output *video)
{
	pthread_mutex_lock(&video->data_mutex);

	if (video->next_frame) {
		video->cur_frame = video->next_frame;
		video->next_frame = NULL;
	}

	pthread_mutex_unlock(&video->data_mutex);
}

static void *video_thread(void *param)
{
	struct video_output *video = param;
	uint64_t cur_time = os_gettime_ns();

	while (event_try(&video->stop_event) == EAGAIN) {
		/* wait half a frame, update frame */
		os_sleepto_ns(cur_time += (video->frame_time/2));
		video->cur_video_time = cur_time;
		event_signal(&video->update_event);

		/* wait another half a frame, swap and output frames */
		os_sleepto_ns(cur_time += (video->frame_time/2));
		video_swapframes(video);
		if (video->cur_frame)
			media_output_data(video->output, video->cur_frame);
	}

	return NULL;
}

/* ------------------------------------------------------------------------- */

static inline bool valid_video_params(struct video_info *info)
{
	return info->height != 0 && info->width != 0 && info->fps_den != 0 &&
	       info->fps_num != 0;
}

static inline bool vo_add_to_media(video_t video)
{
	struct media_output_info oi;
	oi.obj     = video;
	oi.connect = NULL;

	video->output = media_output_create(&oi);
	if (!video->output)
		return false;

	media_add_output(video->media, video->output);
	return true;
}

int video_output_open(video_t *video, media_t media, struct video_info *info)
{
	struct video_output *out;

	if (!valid_video_params(info))
		return VIDEO_OUTPUT_INVALIDPARAM;

	out = bmalloc(sizeof(struct video_output));
	memset(out, 0, sizeof(struct video_output));

	memcpy(&out->info, info, sizeof(struct video_info));
	out->frame_time = (uint64_t)(1000000000.0 * (double)info->fps_den /
		(double)info->fps_num);
	out->media = media;
	out->initialized = false;

	if (pthread_mutex_init(&out->data_mutex, NULL) != 0)
		goto fail;
	if (event_init(&out->stop_event, true) != 0)
		goto fail;
	if (event_init(&out->update_event, false) != 0)
		goto fail;
	if (!vo_add_to_media(out))
		goto fail;
	if (pthread_create(&out->thread, NULL, video_thread, out) != 0)
		goto fail;

	out->initialized = true;
	*video = out;
	return VIDEO_OUTPUT_SUCCESS;

fail:
	video_output_close(out);
	return VIDEO_OUTPUT_FAIL;
}

const struct video_info *video_output_getinfo(video_t video)
{
	return &video->info;
}

void video_output_frame(video_t video, struct video_frame *frame)
{
	pthread_mutex_lock(&video->data_mutex);
	video->next_frame = frame;
	pthread_mutex_unlock(&video->data_mutex);
}

bool video_output_wait(video_t video)
{
	event_wait(&video->update_event);
	return event_try(&video->stop_event) == EAGAIN;
}

uint64_t video_getframetime(video_t video)
{
	return video->frame_time;
}

uint64_t video_gettime(video_t video)
{
	return video->cur_video_time;
}

void video_output_stop(video_t video)
{
	void *thread_ret;

	if (!video)
		return;

	if (video->initialized) {
		event_signal(&video->stop_event);
		pthread_join(video->thread, &thread_ret);
		event_signal(&video->update_event);
	}
}

void video_output_close(video_t video)
{
	if (!video)
		return;

	video_output_stop(video);

	if (video->output) {
		media_remove_output(video->media, video->output);
		media_output_destroy(video->output);
	}

	event_destroy(&video->update_event);
	event_destroy(&video->stop_event);
	pthread_mutex_destroy(&video->data_mutex);
	bfree(video);
}