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+/*
+ * 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>
+
+#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>
+
+#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;
+
+ /* pts of the next frame that will be generated */
+ int64_t next_pts;
+
+ AVFrame *frame;
+ AVFrame *tmp_frame;
+
+ float t, tincr, tincr2;
+
+ struct SwsContext *sws_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;
+
+ /* 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, *codec);
+ if (!ost->st) {
+ fprintf(stderr, "Could not allocate stream\n");
+ exit(1);
+ }
+ ost->st->id = oc->nb_streams-1;
+ c = ost->st->codec;
+
+ 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;
+ c->channels = 2;
+ c->channel_layout = AV_CH_LAYOUT_STEREO;
+ 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. */
+ c->time_base.den = STREAM_FRAME_RATE;
+ c->time_base.num = 1;
+ 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 |= CODEC_FLAG_GLOBAL_HEADER;
+}
+
+/**************************************************************/
+/* audio output */
+
+int samples_count;
+
+struct SwrContext *swr_ctx = NULL;
+
+static void open_audio(AVFormatContext *oc, AVCodec *codec, OutputStream *ost)
+{
+ AVCodecContext *c;
+ int ret;
+
+ c = ost->st->codec;
+
+ /* open it */
+ ret = avcodec_open2(c, codec, NULL);
+ 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;
+
+ ost->frame = av_frame_alloc();
+ if (!ost->frame)
+ exit(1);
+
+ ost->frame->sample_rate = c->sample_rate;
+ ost->frame->format = AV_SAMPLE_FMT_S16;
+ ost->frame->channel_layout = c->channel_layout;
+
+ if (c->codec->capabilities & CODEC_CAP_VARIABLE_FRAME_SIZE)
+ ost->frame->nb_samples = 10000;
+ else
+ ost->frame->nb_samples = c->frame_size;
+
+ ost->tmp_frame = av_frame_alloc();
+ if (!ost->frame)
+ exit(1);
+
+ ost->tmp_frame->sample_rate = c->sample_rate;
+ ost->tmp_frame->format = c->sample_fmt;
+ ost->tmp_frame->channel_layout = c->channel_layout;
+ ost->tmp_frame->nb_samples = ost->frame->nb_samples;
+
+ /* create resampler context */
+ if (c->sample_fmt != AV_SAMPLE_FMT_S16) {
+ swr_ctx = swr_alloc();
+ if (!swr_ctx) {
+ fprintf(stderr, "Could not allocate resampler context\n");
+ exit(1);
+ }
+
+ /* set options */
+ av_opt_set_int (swr_ctx, "in_channel_count", c->channels, 0);
+ av_opt_set_int (swr_ctx, "in_sample_rate", c->sample_rate, 0);
+ av_opt_set_sample_fmt(swr_ctx, "in_sample_fmt", AV_SAMPLE_FMT_S16, 0);
+ av_opt_set_int (swr_ctx, "out_channel_count", c->channels, 0);
+ av_opt_set_int (swr_ctx, "out_sample_rate", c->sample_rate, 0);
+ av_opt_set_sample_fmt(swr_ctx, "out_sample_fmt", c->sample_fmt, 0);
+
+ /* initialize the resampling context */
+ if ((ret = swr_init(swr_ctx)) < 0) {
+ fprintf(stderr, "Failed to initialize the resampling context\n");
+ exit(1);
+ }
+ }
+
+ ret = av_frame_get_buffer(ost->frame, 0);
+ if (ret < 0) {
+ fprintf(stderr, "Could not allocate an audio frame.\n");
+ exit(1);
+ }
+ ret = av_frame_get_buffer(ost->tmp_frame, 0);
+ if (ret < 0) {
+ fprintf(stderr, "Could not allocate an audio frame.\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)
+{
+ int j, i, v, ret;
+ int16_t *q = (int16_t*)ost->frame->data[0];
+
+ /* check if we want to generate more frames */
+ if (av_compare_ts(ost->next_pts, ost->st->codec->time_base,
+ STREAM_DURATION, (AVRational){ 1, 1 }) >= 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
+ */
+ ret = av_frame_make_writable(ost->frame);
+ if (ret < 0)
+ exit(1);
+
+ for (j = 0; j < ost->frame->nb_samples; j++) {
+ v = (int)(sin(ost->t) * 10000);
+ for (i = 0; i < ost->st->codec->channels; i++)
+ *q++ = v;
+ ost->t += ost->tincr;
+ ost->tincr += ost->tincr2;
+ }
+
+ ost->frame->pts = ost->next_pts;
+ ost->next_pts += ost->frame->nb_samples;
+
+ return ost->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->st->codec;
+
+ frame = get_audio_frame(ost);
+
+ if (frame) {
+ /* convert samples from native format to destination codec format, using the resampler */
+ if (swr_ctx) {
+ /* compute destination number of samples */
+ dst_nb_samples = av_rescale_rnd(swr_get_delay(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);
+
+ /* convert to destination format */
+ ret = swr_convert(swr_ctx,
+ ost->tmp_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->tmp_frame;
+ } else {
+ dst_nb_samples = frame->nb_samples;
+ }
+
+ frame->pts = av_rescale_q(samples_count, (AVRational){1, c->sample_rate}, c->time_base);
+ 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)
+{
+ int ret;
+ AVCodecContext *c = ost->st->codec;
+
+ /* open the codec */
+ ret = avcodec_open2(c, codec, NULL);
+ 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);
+ }
+ }
+}
+
+/* Prepare a dummy image. */
+static void fill_yuv_image(AVFrame *pict, int frame_index,
+ int width, int height)
+{
+ int x, y, i, ret;
+
+ /* 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(pict);
+ if (ret < 0)
+ exit(1);
+
+ 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->st->codec;
+
+ /* check if we want to generate more frames */
+ if (av_compare_ts(ost->next_pts, ost->st->codec->time_base,
+ STREAM_DURATION, (AVRational){ 1, 1 }) >= 0)
+ return NULL;
+
+ 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;
+
+ c = ost->st->codec;
+
+ frame = get_video_frame(ost);
+
+ if (oc->oformat->flags & AVFMT_RAWPICTURE) {
+ /* a hack to avoid data copy with some raw video muxers */
+ AVPacket pkt;
+ av_init_packet(&pkt);
+
+ if (!frame)
+ return 1;
+
+ pkt.flags |= AV_PKT_FLAG_KEY;
+ pkt.stream_index = ost->st->index;
+ pkt.data = (uint8_t *)frame;
+ pkt.size = sizeof(AVPicture);
+
+ pkt.pts = pkt.dts = frame->pts;
+ av_packet_rescale_ts(&pkt, c->time_base, ost->st->time_base);
+
+ ret = av_interleaved_write_frame(oc, &pkt);
+ } else {
+ AVPacket pkt = { 0 };
+ 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_close(ost->st->codec);
+ av_frame_free(&ost->frame);
+ av_frame_free(&ost->tmp_frame);
+ sws_freeContext(ost->sws_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;
+
+ /* Initialize libavcodec, and register all codecs and formats. */
+ av_register_all();
+
+ 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];
+
+ /* allocate the output media context */
+ avformat_alloc_output_context2(&oc, NULL, NULL, filename);
+ if (!oc) {
+ 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;
+
+ /* Add the audio and video streams using the default format codecs
+ * and initialize the codecs. */
+ if (fmt->video_codec != AV_CODEC_ID_NONE) {
+ add_stream(&video_st, oc, &video_codec, fmt->video_codec);
+ have_video = 1;
+ encode_video = 1;
+ }
+ if (fmt->audio_codec != AV_CODEC_ID_NONE) {
+ 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);
+
+ if (have_audio)
+ open_audio(oc, audio_codec, &audio_st);
+
+ 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, NULL);
+ if (ret < 0) {
+ fprintf(stderr, "Error occurred when opening output file: %s\n",
+ av_err2str(ret));
+ return 1;
+ }
+
+ while (encode_video || encode_audio) {
+ /* select the stream to encode */
+ if (encode_video &&
+ (!encode_audio || av_compare_ts(video_st.next_pts, video_st.st->codec->time_base,
+ audio_st.next_pts, audio_st.st->codec->time_base) <= 0)) {
+ encode_video = !write_video_frame(oc, &video_st);
+ } else {
+ encode_audio = !write_audio_frame(oc, &audio_st);
+ }
+ }
+
+ /* 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_close(oc->pb);
+
+ /* free the stream */
+ avformat_free_context(oc);
+
+ return 0;
+}
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