muxing

/*
* Copyright (c) 2003 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/

/**
* @file
* libavformat API example.
*
* Output a media file in any supported libavformat format. The default
* codecs are used.
* @example muxing.c
*/


#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>

extern "C"
{
#include <libavutil/avassert.h>
#include <libavutil/channel_layout.h>
#include <libavutil/opt.h>
#include <libavutil/mathematics.h>
#include <libavutil/timestamp.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libswresample/swresample.h>
};


char av_error[AV_ERROR_MAX_STRING_SIZE] = { 0 };
#define av_err2str(errnum) av_make_error_string(av_error, AV_ERROR_MAX_STRING_SIZE, errnum)
#define av_ts2str(errnum) av_make_error_string(av_error, AV_ERROR_MAX_STRING_SIZE, errnum)
#define av_ts2timestr(errnum) av_make_error_string(av_error, AV_ERROR_MAX_STRING_SIZE, errnum)



#define STREAM_DURATION   10.0
#define STREAM_FRAME_RATE 25 /* 25 images/s */
#define STREAM_PIX_FMT    AV_PIX_FMT_YUV420P /* default pix_fmt */

#define SCALE_FLAGS SWS_BICUBIC

// a wrapper around a single output AVStream
typedef struct OutputStream {
	AVStream *st;
	AVCodecContext *enc;

	/* pts of the next frame that will be generated */
	int64_t next_pts;
	int samples_count;

	AVFrame *frame;
	AVFrame *tmp_frame;

	float t, tincr, tincr2;

	struct SwsContext *sws_ctx;
	struct SwrContext *swr_ctx;
} OutputStream;

static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt)
{
	AVRational *time_base = &fmt_ctx->streams[pkt->stream_index]->time_base;

	printf("pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n",
		av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, time_base),
		av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, time_base),
		av_ts2str(pkt->duration), av_ts2timestr(pkt->duration, time_base),
		pkt->stream_index);
}

static int write_frame(AVFormatContext *fmt_ctx, const AVRational *time_base, AVStream *st, AVPacket *pkt)
{
	/* rescale output packet timestamp values from codec to stream timebase */
	av_packet_rescale_ts(pkt, *time_base, st->time_base);
	pkt->stream_index = st->index;

	/* Write the compressed frame to the media file. */
	log_packet(fmt_ctx, pkt);
	return av_interleaved_write_frame(fmt_ctx, pkt);
}

/* Add an output stream. */
static void add_stream(OutputStream *ost, AVFormatContext *oc,
	AVCodec **codec,
	enum AVCodecID codec_id)
{
	AVCodecContext *c;
	int i;

	/* find the encoder */
	*codec = avcodec_find_encoder(codec_id);
	if (!(*codec)) {
		fprintf(stderr, "Could not find encoder for '%s'\n",
			avcodec_get_name(codec_id));
		exit(1);
	}

	ost->st = avformat_new_stream(oc, NULL);
	if (!ost->st) {
		fprintf(stderr, "Could not allocate stream\n");
		exit(1);
	}
	ost->st->id = oc->nb_streams - 1;
	c = avcodec_alloc_context3(*codec);
	if (!c) {
		fprintf(stderr, "Could not alloc an encoding context\n");
		exit(1);
	}
	ost->enc = c;

	AVRational avrr;
	switch ((*codec)->type) {
	case AVMEDIA_TYPE_AUDIO:
		c->sample_fmt = (*codec)->sample_fmts ?
			(*codec)->sample_fmts[0] : AV_SAMPLE_FMT_FLTP;
		c->bit_rate = 64000;
		c->sample_rate = 44100;
		if ((*codec)->supported_samplerates) {
			c->sample_rate = (*codec)->supported_samplerates[0];
			for (i = 0; (*codec)->supported_samplerates[i]; i++) {
				if ((*codec)->supported_samplerates[i] == 44100)
					c->sample_rate = 44100;
			}
		}
		c->channels = av_get_channel_layout_nb_channels(c->channel_layout);
		c->channel_layout = AV_CH_LAYOUT_STEREO;
		if ((*codec)->channel_layouts) {
			c->channel_layout = (*codec)->channel_layouts[0];
			for (i = 0; (*codec)->channel_layouts[i]; i++) {
				if ((*codec)->channel_layouts[i] == AV_CH_LAYOUT_STEREO)
					c->channel_layout = AV_CH_LAYOUT_STEREO;
			}
		}
		c->channels = av_get_channel_layout_nb_channels(c->channel_layout);

		avrr = { 1, c->sample_rate };
		
		ost->st->time_base = avrr;
		break;

	case AVMEDIA_TYPE_VIDEO:
		c->codec_id = codec_id;

		c->bit_rate = 400000;
		/* Resolution must be a multiple of two. */
		c->width = 352;
		c->height = 288;
		/* timebase: This is the fundamental unit of time (in seconds) in terms
		* of which frame timestamps are represented. For fixed-fps content,
		* timebase should be 1/framerate and timestamp increments should be
		* identical to 1. */
		AVRational avr = { 1, STREAM_FRAME_RATE };
		ost->st->time_base = avr;
		c->time_base = ost->st->time_base;

		c->gop_size = 12; /* emit one intra frame every twelve frames at most */
		c->pix_fmt = STREAM_PIX_FMT;
		if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
			/* just for testing, we also add B-frames */
			c->max_b_frames = 2;
		}
		if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
			/* Needed to avoid using macroblocks in which some coeffs overflow.
			* This does not happen with normal video, it just happens here as
			* the motion of the chroma plane does not match the luma plane. */
			c->mb_decision = 2;
		}
		break;

	//default:
		//break;
	}

	/* Some formats want stream headers to be separate. */
	if (oc->oformat->flags & AVFMT_GLOBALHEADER)
		c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
}

/**************************************************************/
/* audio output */

static AVFrame *alloc_audio_frame(enum AVSampleFormat sample_fmt,
	uint64_t channel_layout,
	int sample_rate, int nb_samples)
{
	AVFrame *frame = av_frame_alloc();
	int ret;

	if (!frame) {
		fprintf(stderr, "Error allocating an audio frame\n");
		exit(1);
	}

	frame->format = sample_fmt;
	frame->channel_layout = channel_layout;
	frame->sample_rate = sample_rate;
	frame->nb_samples = nb_samples;

	if (nb_samples) {
		ret = av_frame_get_buffer(frame, 0);
		if (ret < 0) {
			fprintf(stderr, "Error allocating an audio buffer\n");
			exit(1);
		}
	}

	return frame;
}

static void open_audio(AVFormatContext *oc, AVCodec *codec, OutputStream *ost, AVDictionary *opt_arg)
{
	AVCodecContext *c;
	int nb_samples;
	int ret;
	AVDictionary *opt = NULL;

	c = ost->enc;

	/* open it */
	av_dict_copy(&opt, opt_arg, 0);
	ret = avcodec_open2(c, codec, &opt);
	av_dict_free(&opt);
	if (ret < 0) {
		fprintf(stderr, "Could not open audio codec: %s\n", av_err2str(ret));
		exit(1);
	}

	/* init signal generator */
	ost->t = 0;
	ost->tincr = 2 * M_PI * 110.0 / c->sample_rate;
	/* increment frequency by 110 Hz per second */
	ost->tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate;

	if (c->codec->capabilities & AV_CODEC_CAP_VARIABLE_FRAME_SIZE)
		nb_samples = 10000;
	else
		nb_samples = c->frame_size;

	ost->frame = alloc_audio_frame(c->sample_fmt, c->channel_layout,
		c->sample_rate, nb_samples);
	ost->tmp_frame = alloc_audio_frame(AV_SAMPLE_FMT_S16, c->channel_layout,
		c->sample_rate, nb_samples);

	/* copy the stream parameters to the muxer */
	ret = avcodec_parameters_from_context(ost->st->codecpar, c);
	if (ret < 0) {
		fprintf(stderr, "Could not copy the stream parameters\n");
		exit(1);
	}

	/* create resampler context */
	ost->swr_ctx = swr_alloc();
	if (!ost->swr_ctx) {
		fprintf(stderr, "Could not allocate resampler context\n");
		exit(1);
	}

	/* set options */
	av_opt_set_int(ost->swr_ctx, "in_channel_count", c->channels, 0);
	av_opt_set_int(ost->swr_ctx, "in_sample_rate", c->sample_rate, 0);
	av_opt_set_sample_fmt(ost->swr_ctx, "in_sample_fmt", AV_SAMPLE_FMT_S16, 0);
	av_opt_set_int(ost->swr_ctx, "out_channel_count", c->channels, 0);
	av_opt_set_int(ost->swr_ctx, "out_sample_rate", c->sample_rate, 0);
	av_opt_set_sample_fmt(ost->swr_ctx, "out_sample_fmt", c->sample_fmt, 0);

	/* initialize the resampling context */
	if ((ret = swr_init(ost->swr_ctx)) < 0) {
		fprintf(stderr, "Failed to initialize the resampling context\n");
		exit(1);
	}
}

/* Prepare a 16 bit dummy audio frame of 'frame_size' samples and
* 'nb_channels' channels. */
static AVFrame *get_audio_frame(OutputStream *ost)
{
	AVFrame *frame = ost->tmp_frame;
	int j, i, v;
	int16_t *q = (int16_t*)frame->data[0];
	AVRational avr = { 1, 1 };
	/* check if we want to generate more frames */
	if (av_compare_ts(ost->next_pts, ost->enc->time_base,
		STREAM_DURATION, avr) >= 0)
		return NULL;

	for (j = 0; j <frame->nb_samples; j++) {
		v = (int)(sin(ost->t) * 10000);
		for (i = 0; i < ost->enc->channels; i++)
			*q++ = v;
		ost->t += ost->tincr;
		ost->tincr += ost->tincr2;
	}

	frame->pts = ost->next_pts;
	ost->next_pts += frame->nb_samples;

	return frame;
}

/*
* encode one audio frame and send it to the muxer
* return 1 when encoding is finished, 0 otherwise
*/
static int write_audio_frame(AVFormatContext *oc, OutputStream *ost)
{
	AVCodecContext *c;
	AVPacket pkt = { 0 }; // data and size must be 0;
	AVFrame *frame;
	int ret;
	int got_packet;
	int dst_nb_samples;

	av_init_packet(&pkt);
	c = ost->enc;

	frame = get_audio_frame(ost);

	if (frame) {
		/* convert samples from native format to destination codec format, using the resampler */
		/* compute destination number of samples */
		dst_nb_samples = av_rescale_rnd(swr_get_delay(ost->swr_ctx, c->sample_rate) + frame->nb_samples,
			c->sample_rate, c->sample_rate, AV_ROUND_UP);
		av_assert0(dst_nb_samples == frame->nb_samples);

		/* when we pass a frame to the encoder, it may keep a reference to it
		* internally;
		* make sure we do not overwrite it here
		*/
		ret = av_frame_make_writable(ost->frame);
		if (ret < 0)
			exit(1);

		/* convert to destination format */
		ret = swr_convert(ost->swr_ctx,
			ost->frame->data, dst_nb_samples,
			(const uint8_t **)frame->data, frame->nb_samples);
		if (ret < 0) {
			fprintf(stderr, "Error while converting\n");
			exit(1);
		}
		frame = ost->frame;
		AVRational avr = { 1, c->sample_rate };
		frame->pts = av_rescale_q(ost->samples_count, avr, c->time_base);
		ost->samples_count += dst_nb_samples;
	}

	ret = avcodec_encode_audio2(c, &pkt, frame, &got_packet);
	if (ret < 0) {
		fprintf(stderr, "Error encoding audio frame: %s\n", av_err2str(ret));
		exit(1);
	}

	if (got_packet) {
		ret = write_frame(oc, &c->time_base, ost->st, &pkt);
		if (ret < 0) {
			fprintf(stderr, "Error while writing audio frame: %s\n",
				av_err2str(ret));
			exit(1);
		}
	}

	return (frame || got_packet) ? 0 : 1;
}

/**************************************************************/
/* video output */

static AVFrame *alloc_picture(enum AVPixelFormat pix_fmt, int width, int height)
{
	AVFrame *picture;
	int ret;

	picture = av_frame_alloc();
	if (!picture)
		return NULL;

	picture->format = pix_fmt;
	picture->width = width;
	picture->height = height;

	/* allocate the buffers for the frame data */
	ret = av_frame_get_buffer(picture, 32);
	if (ret < 0) {
		fprintf(stderr, "Could not allocate frame data.\n");
		exit(1);
	}

	return picture;
}

static void open_video(AVFormatContext *oc, AVCodec *codec, OutputStream *ost, AVDictionary *opt_arg)
{
	int ret;
	AVCodecContext *c = ost->enc;
	AVDictionary *opt = NULL;

	av_dict_copy(&opt, opt_arg, 0);

	/* open the codec */
	ret = avcodec_open2(c, codec, &opt);
	av_dict_free(&opt);
	if (ret < 0) {
		fprintf(stderr, "Could not open video codec: %s\n", av_err2str(ret));
		exit(1);
	}

	/* allocate and init a re-usable frame */
	ost->frame = alloc_picture(c->pix_fmt, c->width, c->height);
	if (!ost->frame) {
		fprintf(stderr, "Could not allocate video frame\n");
		exit(1);
	}

	/* If the output format is not YUV420P, then a temporary YUV420P
	* picture is needed too. It is then converted to the required
	* output format. */
	ost->tmp_frame = NULL;
	if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
		ost->tmp_frame = alloc_picture(AV_PIX_FMT_YUV420P, c->width, c->height);
		if (!ost->tmp_frame) {
			fprintf(stderr, "Could not allocate temporary picture\n");
			exit(1);
		}
	}

	/* copy the stream parameters to the muxer */
	ret = avcodec_parameters_from_context(ost->st->codecpar, c);
	if (ret < 0) {
		fprintf(stderr, "Could not copy the stream parameters\n");
		exit(1);
	}
}

/* Prepare a dummy image. */
static void fill_yuv_image(AVFrame *pict, int frame_index,
	int width, int height)
{
	int x, y, i;

	i = frame_index;

	/* Y */
	for (y = 0; y < height; y++)
		for (x = 0; x < width; x++)
			pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;

	/* Cb and Cr */
	for (y = 0; y < height / 2; y++) {
		for (x = 0; x < width / 2; x++) {
			pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
			pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5;
		}
	}
}

static AVFrame *get_video_frame(OutputStream *ost)
{
	AVCodecContext *c = ost->enc;
	AVRational avr = { 1, 1 };
	/* check if we want to generate more frames */
	if (av_compare_ts(ost->next_pts, c->time_base,STREAM_DURATION, avr) >= 0)
		return NULL;

	/* when we pass a frame to the encoder, it may keep a reference to it
	* internally; make sure we do not overwrite it here */
	if (av_frame_make_writable(ost->frame) < 0)
		exit(1);

	if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
		/* as we only generate a YUV420P picture, we must convert it
		* to the codec pixel format if needed */
		if (!ost->sws_ctx) {
			ost->sws_ctx = sws_getContext(c->width, c->height,
				AV_PIX_FMT_YUV420P,
				c->width, c->height,
				c->pix_fmt,
				SCALE_FLAGS, NULL, NULL, NULL);
			if (!ost->sws_ctx) {
				fprintf(stderr,
					"Could not initialize the conversion context\n");
				exit(1);
			}
		}
		fill_yuv_image(ost->tmp_frame, ost->next_pts, c->width, c->height);
		sws_scale(ost->sws_ctx, (const uint8_t * const *)ost->tmp_frame->data,
			ost->tmp_frame->linesize, 0, c->height, ost->frame->data,
			ost->frame->linesize);
	}
	else {
		fill_yuv_image(ost->frame, ost->next_pts, c->width, c->height);
	}

	ost->frame->pts = ost->next_pts++;

	return ost->frame;
}

/*
* encode one video frame and send it to the muxer
* return 1 when encoding is finished, 0 otherwise
*/
static int write_video_frame(AVFormatContext *oc, OutputStream *ost)
{
	int ret;
	AVCodecContext *c;
	AVFrame *frame;
	int got_packet = 0;
	AVPacket pkt = { 0 };

	c = ost->enc;

	frame = get_video_frame(ost);

	av_init_packet(&pkt);

	/* encode the image */
	ret = avcodec_encode_video2(c, &pkt, frame, &got_packet);
	if (ret < 0) {
		fprintf(stderr, "Error encoding video frame: %s\n", av_err2str(ret));
		exit(1);
	}

	if (got_packet) 
	{
		ret = write_frame(oc, &c->time_base, ost->st, &pkt);
	}
	else {
		ret = 0;
	}

	if (ret < 0) {
		fprintf(stderr, "Error while writing video frame: %s\n", av_err2str(ret));
		exit(1);
	}

	return (frame || got_packet) ? 0 : 1;
}

static void close_stream(AVFormatContext *oc, OutputStream *ost)
{
	avcodec_free_context(&ost->enc);
	av_frame_free(&ost->frame);
	av_frame_free(&ost->tmp_frame);
	sws_freeContext(ost->sws_ctx);
	swr_free(&ost->swr_ctx);
}

/**************************************************************/
/* media file output */

int main(int argc, char **argv)
{
	OutputStream video_st = { 0 }, audio_st = { 0 };
	const char *filename;
	AVOutputFormat *fmt;
	AVFormatContext *oc;
	AVCodec *audio_codec, *video_codec;
	int ret;
	int have_video = 0, have_audio = 0;
	int encode_video = 0, encode_audio = 0;
	AVDictionary *opt = NULL;
	int i;

#if 0
	if (argc < 2) {
		printf("usage: %s output_file\n"
			"API example program to output a media file with libavformat.\n"
			"This program generates a synthetic audio and video stream, encodes and\n"
			"muxes them into a file named output_file.\n"
			"The output format is automatically guessed according to the file extension.\n"
			"Raw images can also be output by using '%%d' in the filename.\n"
			"\n", argv[0]);
		return 1;
}

	filename = argv[1];
#endif // 0



	filename = "C:\\VLC\\output.mp4";
	for (i = 2; i + 1 < argc; i += 2) 
	{
		if (!strcmp(argv[i], "-flags") || !strcmp(argv[i], "-fflags"))
		{
			printf("[NOTE]FUNCTION: %s LINE:%d\n", __FUNCTION__, __LINE__);
			av_dict_set(&opt, argv[i] + 1, argv[i + 1], 0);
		}
	}

	/* allocate the output media context */
	avformat_alloc_output_context2(&oc, NULL, NULL, filename);
	if (!oc) 
	{
		printf("[NOTE]FUNCTION: %s LINE:%d\n", __FUNCTION__, __LINE__);
		printf("Could not deduce output format from file extension: using MPEG.\n");
		avformat_alloc_output_context2(&oc, NULL, "mpeg", filename);
	}
	if (!oc)
		return 1;

	fmt = oc->oformat;
	printf("[NOTE]FUNCTION: %s LINE:%d\n", __FUNCTION__, __LINE__);
	printf("oc->oformat->name: %s\n", oc->oformat->name);


	/* Add the audio and video streams using the default format codecs
	* and initialize the codecs. */
	if (fmt->video_codec != AV_CODEC_ID_NONE) 
	{
		printf("fmt->video_codec: %d\n", fmt->video_codec); //AV_CODEC_ID_H264
		add_stream(&video_st, oc, &video_codec, fmt->video_codec);
		have_video = 1;
		encode_video = 1;
	}
	if (fmt->audio_codec != AV_CODEC_ID_NONE) 
	{
		printf("fmt->audio_codec: %d\n", fmt->audio_codec); //AV_CODEC_ID_AAC
		add_stream(&audio_st, oc, &audio_codec, fmt->audio_codec);
		have_audio = 1;
		encode_audio = 1;
	}




	/* Now that all the parameters are set, we can open the audio and
	* video codecs and allocate the necessary encode buffers. */
	if (have_video)
	{
		open_video(oc, video_codec, &video_st, opt);
	}

	if (have_audio)
	{
		open_audio(oc, audio_codec, &audio_st, opt);
	}


	av_dump_format(oc, 0, filename, 1);


	/* open the output file, if needed */
	if (!(fmt->flags & AVFMT_NOFILE)) 
	{

		ret = avio_open(&oc->pb, filename, AVIO_FLAG_WRITE);
		if (ret < 0) 
		{
			fprintf(stderr, "Could not open '%s': %s\n", filename,
				av_err2str(ret));
			return 1;
		}
	}




	/* Write the stream header, if any. */
	ret = avformat_write_header(oc, &opt);
	if (ret < 0) 
	{
		fprintf(stderr, "Error occurred when opening output file: %s\n",av_err2str(ret));
		return 1;
	}


	while (encode_video || encode_audio) 
	{
		printf("encode_video:%d encode_audio:%d\n", encode_video, encode_audio);
		/* select the stream to encode */
		if (encode_video &&
			(!encode_audio || av_compare_ts(video_st.next_pts, video_st.enc->time_base,
				audio_st.next_pts, audio_st.enc->time_base) <= 0)) 
		{
			printf("[NOTE]FUNCTION: %s LINE:%d\n", __FUNCTION__, __LINE__);

			encode_video = !write_video_frame(oc, &video_st);
		}
		else 
		{
			printf("[NOTE]FUNCTION: %s LINE:%d\n", __FUNCTION__, __LINE__);

			encode_audio = !write_audio_frame(oc, &audio_st);
		}
		//getchar();
	}



	/* Write the trailer, if any. The trailer must be written before you
	* close the CodecContexts open when you wrote the header; otherwise
	* av_write_trailer() may try to use memory that was freed on
	* av_codec_close(). */
	av_write_trailer(oc);

	/* Close each codec. */
	if (have_video)
		close_stream(oc, &video_st);
	if (have_audio)
		close_stream(oc, &audio_st);

	if (!(fmt->flags & AVFMT_NOFILE))
		/* Close the output file. */
		avio_closep(&oc->pb);

	/* free the stream */
	avformat_free_context(oc);

	return 0;
}