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authorStefano Sabatini <stefano.sabatini-lala@poste.it>2011-05-29 14:47:40 +0400
committerStefano Sabatini <stefano.sabatini-lala@poste.it>2011-05-30 11:20:06 +0400
commit9362b5094114bd2f0cea74691ad900b19dac64f8 (patch)
treeb086f7827b6ec71ab965fe48df268d6c6b7b4a0e /doc
parentf712f6c8a4bd14bae3c41118af642b5dae7f6e2b (diff)
examples: move API examples to a dedicated dir in doc
Diffstat (limited to 'doc')
-rw-r--r--doc/examples/Makefile21
-rw-r--r--doc/examples/api-example.c467
-rw-r--r--doc/examples/output-example.c538
3 files changed, 1026 insertions, 0 deletions
diff --git a/doc/examples/Makefile b/doc/examples/Makefile
new file mode 100644
index 0000000000..facbd7e178
--- /dev/null
+++ b/doc/examples/Makefile
@@ -0,0 +1,21 @@
+# use pkg-config for getting CFLAGS abd LDFLAGS
+FFMPEG_LIBS=libavdevice libavformat libavfilter libavcodec libswscale libavutil
+CFLAGS+=$(shell pkg-config --cflags $(FFMPEG_LIBS))
+LDFLAGS+=$(shell pkg-config --libs $(FFMPEG_LIBS))
+
+EXAMPLES=api-example output-example
+
+OBJS=$(addsuffix .o,$(EXAMPLES))
+
+%: %.o
+ $(CC) $< $(LDFLAGS) -o $@
+
+%.o: %.c
+ $(CC) $< $(CFLAGS) -c -o $@
+
+.phony: all clean
+
+all: $(OBJS) $(EXAMPLES)
+
+clean:
+ rm -rf $(EXAMPLES) $(OBJS)
diff --git a/doc/examples/api-example.c b/doc/examples/api-example.c
new file mode 100644
index 0000000000..f34075e666
--- /dev/null
+++ b/doc/examples/api-example.c
@@ -0,0 +1,467 @@
+/*
+ * copyright (c) 2001 Fabrice Bellard
+ *
+ * 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
+ * avcodec API use example.
+ *
+ * Note that this library only handles codecs (mpeg, mpeg4, etc...),
+ * not file formats (avi, vob, etc...). See library 'libavformat' for the
+ * format handling
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#ifdef HAVE_AV_CONFIG_H
+#undef HAVE_AV_CONFIG_H
+#endif
+
+#include "libavcodec/avcodec.h"
+#include "libavutil/mathematics.h"
+
+#define INBUF_SIZE 4096
+#define AUDIO_INBUF_SIZE 20480
+#define AUDIO_REFILL_THRESH 4096
+
+/*
+ * Audio encoding example
+ */
+static void audio_encode_example(const char *filename)
+{
+ AVCodec *codec;
+ AVCodecContext *c= NULL;
+ int frame_size, i, j, out_size, outbuf_size;
+ FILE *f;
+ short *samples;
+ float t, tincr;
+ uint8_t *outbuf;
+
+ printf("Audio encoding\n");
+
+ /* find the MP2 encoder */
+ codec = avcodec_find_encoder(CODEC_ID_MP2);
+ if (!codec) {
+ fprintf(stderr, "codec not found\n");
+ exit(1);
+ }
+
+ c= avcodec_alloc_context();
+
+ /* put sample parameters */
+ c->bit_rate = 64000;
+ c->sample_rate = 44100;
+ c->channels = 2;
+
+ /* open it */
+ if (avcodec_open(c, codec) < 0) {
+ fprintf(stderr, "could not open codec\n");
+ exit(1);
+ }
+
+ /* the codec gives us the frame size, in samples */
+ frame_size = c->frame_size;
+ samples = malloc(frame_size * 2 * c->channels);
+ outbuf_size = 10000;
+ outbuf = malloc(outbuf_size);
+
+ f = fopen(filename, "wb");
+ if (!f) {
+ fprintf(stderr, "could not open %s\n", filename);
+ exit(1);
+ }
+
+ /* encode a single tone sound */
+ t = 0;
+ tincr = 2 * M_PI * 440.0 / c->sample_rate;
+ for(i=0;i<200;i++) {
+ for(j=0;j<frame_size;j++) {
+ samples[2*j] = (int)(sin(t) * 10000);
+ samples[2*j+1] = samples[2*j];
+ t += tincr;
+ }
+ /* encode the samples */
+ out_size = avcodec_encode_audio(c, outbuf, outbuf_size, samples);
+ fwrite(outbuf, 1, out_size, f);
+ }
+ fclose(f);
+ free(outbuf);
+ free(samples);
+
+ avcodec_close(c);
+ av_free(c);
+}
+
+/*
+ * Audio decoding.
+ */
+static void audio_decode_example(const char *outfilename, const char *filename)
+{
+ AVCodec *codec;
+ AVCodecContext *c= NULL;
+ int out_size, len;
+ FILE *f, *outfile;
+ uint8_t *outbuf;
+ uint8_t inbuf[AUDIO_INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE];
+ AVPacket avpkt;
+
+ av_init_packet(&avpkt);
+
+ printf("Audio decoding\n");
+
+ /* find the mpeg audio decoder */
+ codec = avcodec_find_decoder(CODEC_ID_MP2);
+ if (!codec) {
+ fprintf(stderr, "codec not found\n");
+ exit(1);
+ }
+
+ c= avcodec_alloc_context();
+
+ /* open it */
+ if (avcodec_open(c, codec) < 0) {
+ fprintf(stderr, "could not open codec\n");
+ exit(1);
+ }
+
+ outbuf = malloc(AVCODEC_MAX_AUDIO_FRAME_SIZE);
+
+ f = fopen(filename, "rb");
+ if (!f) {
+ fprintf(stderr, "could not open %s\n", filename);
+ exit(1);
+ }
+ outfile = fopen(outfilename, "wb");
+ if (!outfile) {
+ av_free(c);
+ exit(1);
+ }
+
+ /* decode until eof */
+ avpkt.data = inbuf;
+ avpkt.size = fread(inbuf, 1, AUDIO_INBUF_SIZE, f);
+
+ while (avpkt.size > 0) {
+ out_size = AVCODEC_MAX_AUDIO_FRAME_SIZE;
+ len = avcodec_decode_audio3(c, (short *)outbuf, &out_size, &avpkt);
+ if (len < 0) {
+ fprintf(stderr, "Error while decoding\n");
+ exit(1);
+ }
+ if (out_size > 0) {
+ /* if a frame has been decoded, output it */
+ fwrite(outbuf, 1, out_size, outfile);
+ }
+ avpkt.size -= len;
+ avpkt.data += len;
+ if (avpkt.size < AUDIO_REFILL_THRESH) {
+ /* Refill the input buffer, to avoid trying to decode
+ * incomplete frames. Instead of this, one could also use
+ * a parser, or use a proper container format through
+ * libavformat. */
+ memmove(inbuf, avpkt.data, avpkt.size);
+ avpkt.data = inbuf;
+ len = fread(avpkt.data + avpkt.size, 1,
+ AUDIO_INBUF_SIZE - avpkt.size, f);
+ if (len > 0)
+ avpkt.size += len;
+ }
+ }
+
+ fclose(outfile);
+ fclose(f);
+ free(outbuf);
+
+ avcodec_close(c);
+ av_free(c);
+}
+
+/*
+ * Video encoding example
+ */
+static void video_encode_example(const char *filename)
+{
+ AVCodec *codec;
+ AVCodecContext *c= NULL;
+ int i, out_size, size, x, y, outbuf_size;
+ FILE *f;
+ AVFrame *picture;
+ uint8_t *outbuf, *picture_buf;
+
+ printf("Video encoding\n");
+
+ /* find the mpeg1 video encoder */
+ codec = avcodec_find_encoder(CODEC_ID_MPEG1VIDEO);
+ if (!codec) {
+ fprintf(stderr, "codec not found\n");
+ exit(1);
+ }
+
+ c= avcodec_alloc_context();
+ picture= avcodec_alloc_frame();
+
+ /* put sample parameters */
+ c->bit_rate = 400000;
+ /* resolution must be a multiple of two */
+ c->width = 352;
+ c->height = 288;
+ /* frames per second */
+ c->time_base= (AVRational){1,25};
+ c->gop_size = 10; /* emit one intra frame every ten frames */
+ c->max_b_frames=1;
+ c->pix_fmt = PIX_FMT_YUV420P;
+
+ /* open it */
+ if (avcodec_open(c, codec) < 0) {
+ fprintf(stderr, "could not open codec\n");
+ exit(1);
+ }
+
+ f = fopen(filename, "wb");
+ if (!f) {
+ fprintf(stderr, "could not open %s\n", filename);
+ exit(1);
+ }
+
+ /* alloc image and output buffer */
+ outbuf_size = 100000;
+ outbuf = malloc(outbuf_size);
+ size = c->width * c->height;
+ picture_buf = malloc((size * 3) / 2); /* size for YUV 420 */
+
+ picture->data[0] = picture_buf;
+ picture->data[1] = picture->data[0] + size;
+ picture->data[2] = picture->data[1] + size / 4;
+ picture->linesize[0] = c->width;
+ picture->linesize[1] = c->width / 2;
+ picture->linesize[2] = c->width / 2;
+
+ /* encode 1 second of video */
+ for(i=0;i<25;i++) {
+ fflush(stdout);
+ /* prepare a dummy image */
+ /* Y */
+ for(y=0;y<c->height;y++) {
+ for(x=0;x<c->width;x++) {
+ picture->data[0][y * picture->linesize[0] + x] = x + y + i * 3;
+ }
+ }
+
+ /* Cb and Cr */
+ for(y=0;y<c->height/2;y++) {
+ for(x=0;x<c->width/2;x++) {
+ picture->data[1][y * picture->linesize[1] + x] = 128 + y + i * 2;
+ picture->data[2][y * picture->linesize[2] + x] = 64 + x + i * 5;
+ }
+ }
+
+ /* encode the image */
+ out_size = avcodec_encode_video(c, outbuf, outbuf_size, picture);
+ printf("encoding frame %3d (size=%5d)\n", i, out_size);
+ fwrite(outbuf, 1, out_size, f);
+ }
+
+ /* get the delayed frames */
+ for(; out_size; i++) {
+ fflush(stdout);
+
+ out_size = avcodec_encode_video(c, outbuf, outbuf_size, NULL);
+ printf("write frame %3d (size=%5d)\n", i, out_size);
+ fwrite(outbuf, 1, out_size, f);
+ }
+
+ /* add sequence end code to have a real mpeg file */
+ outbuf[0] = 0x00;
+ outbuf[1] = 0x00;
+ outbuf[2] = 0x01;
+ outbuf[3] = 0xb7;
+ fwrite(outbuf, 1, 4, f);
+ fclose(f);
+ free(picture_buf);
+ free(outbuf);
+
+ avcodec_close(c);
+ av_free(c);
+ av_free(picture);
+ printf("\n");
+}
+
+/*
+ * Video decoding example
+ */
+
+static void pgm_save(unsigned char *buf, int wrap, int xsize, int ysize,
+ char *filename)
+{
+ FILE *f;
+ int i;
+
+ f=fopen(filename,"w");
+ fprintf(f,"P5\n%d %d\n%d\n",xsize,ysize,255);
+ for(i=0;i<ysize;i++)
+ fwrite(buf + i * wrap,1,xsize,f);
+ fclose(f);
+}
+
+static void video_decode_example(const char *outfilename, const char *filename)
+{
+ AVCodec *codec;
+ AVCodecContext *c= NULL;
+ int frame, got_picture, len;
+ FILE *f;
+ AVFrame *picture;
+ uint8_t inbuf[INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE];
+ char buf[1024];
+ AVPacket avpkt;
+
+ av_init_packet(&avpkt);
+
+ /* set end of buffer to 0 (this ensures that no overreading happens for damaged mpeg streams) */
+ memset(inbuf + INBUF_SIZE, 0, FF_INPUT_BUFFER_PADDING_SIZE);
+
+ printf("Video decoding\n");
+
+ /* find the mpeg1 video decoder */
+ codec = avcodec_find_decoder(CODEC_ID_MPEG1VIDEO);
+ if (!codec) {
+ fprintf(stderr, "codec not found\n");
+ exit(1);
+ }
+
+ c= avcodec_alloc_context();
+ picture= avcodec_alloc_frame();
+
+ if(codec->capabilities&CODEC_CAP_TRUNCATED)
+ c->flags|= CODEC_FLAG_TRUNCATED; /* we do not send complete frames */
+
+ /* For some codecs, such as msmpeg4 and mpeg4, width and height
+ MUST be initialized there because this information is not
+ available in the bitstream. */
+
+ /* open it */
+ if (avcodec_open(c, codec) < 0) {
+ fprintf(stderr, "could not open codec\n");
+ exit(1);
+ }
+
+ /* the codec gives us the frame size, in samples */
+
+ f = fopen(filename, "rb");
+ if (!f) {
+ fprintf(stderr, "could not open %s\n", filename);
+ exit(1);
+ }
+
+ frame = 0;
+ for(;;) {
+ avpkt.size = fread(inbuf, 1, INBUF_SIZE, f);
+ if (avpkt.size == 0)
+ break;
+
+ /* NOTE1: some codecs are stream based (mpegvideo, mpegaudio)
+ and this is the only method to use them because you cannot
+ know the compressed data size before analysing it.
+
+ BUT some other codecs (msmpeg4, mpeg4) are inherently frame
+ based, so you must call them with all the data for one
+ frame exactly. You must also initialize 'width' and
+ 'height' before initializing them. */
+
+ /* NOTE2: some codecs allow the raw parameters (frame size,
+ sample rate) to be changed at any frame. We handle this, so
+ you should also take care of it */
+
+ /* here, we use a stream based decoder (mpeg1video), so we
+ feed decoder and see if it could decode a frame */
+ avpkt.data = inbuf;
+ while (avpkt.size > 0) {
+ len = avcodec_decode_video2(c, picture, &got_picture, &avpkt);
+ if (len < 0) {
+ fprintf(stderr, "Error while decoding frame %d\n", frame);
+ exit(1);
+ }
+ if (got_picture) {
+ printf("saving frame %3d\n", frame);
+ fflush(stdout);
+
+ /* the picture is allocated by the decoder. no need to
+ free it */
+ snprintf(buf, sizeof(buf), outfilename, frame);
+ pgm_save(picture->data[0], picture->linesize[0],
+ c->width, c->height, buf);
+ frame++;
+ }
+ avpkt.size -= len;
+ avpkt.data += len;
+ }
+ }
+
+ /* some codecs, such as MPEG, transmit the I and P frame with a
+ latency of one frame. You must do the following to have a
+ chance to get the last frame of the video */
+ avpkt.data = NULL;
+ avpkt.size = 0;
+ len = avcodec_decode_video2(c, picture, &got_picture, &avpkt);
+ if (got_picture) {
+ printf("saving last frame %3d\n", frame);
+ fflush(stdout);
+
+ /* the picture is allocated by the decoder. no need to
+ free it */
+ snprintf(buf, sizeof(buf), outfilename, frame);
+ pgm_save(picture->data[0], picture->linesize[0],
+ c->width, c->height, buf);
+ frame++;
+ }
+
+ fclose(f);
+
+ avcodec_close(c);
+ av_free(c);
+ av_free(picture);
+ printf("\n");
+}
+
+int main(int argc, char **argv)
+{
+ const char *filename;
+
+ /* must be called before using avcodec lib */
+ avcodec_init();
+
+ /* register all the codecs */
+ avcodec_register_all();
+
+ if (argc <= 1) {
+ audio_encode_example("/tmp/test.mp2");
+ audio_decode_example("/tmp/test.sw", "/tmp/test.mp2");
+
+ video_encode_example("/tmp/test.mpg");
+ filename = "/tmp/test.mpg";
+ } else {
+ filename = argv[1];
+ }
+
+ // audio_decode_example("/tmp/test.sw", filename);
+ video_decode_example("/tmp/test%d.pgm", filename);
+
+ return 0;
+}
diff --git a/doc/examples/output-example.c b/doc/examples/output-example.c
new file mode 100644
index 0000000000..f174305fe6
--- /dev/null
+++ b/doc/examples/output-example.c
@@ -0,0 +1,538 @@
+/*
+ * Libavformat API example: Output a media file in any supported
+ * libavformat format. The default codecs are used.
+ *
+ * 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.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <math.h>
+
+#include "libavformat/avformat.h"
+#include "libswscale/swscale.h"
+
+#undef exit
+
+/* 5 seconds stream duration */
+#define STREAM_DURATION 5.0
+#define STREAM_FRAME_RATE 25 /* 25 images/s */
+#define STREAM_NB_FRAMES ((int)(STREAM_DURATION * STREAM_FRAME_RATE))
+#define STREAM_PIX_FMT PIX_FMT_YUV420P /* default pix_fmt */
+
+static int sws_flags = SWS_BICUBIC;
+
+/**************************************************************/
+/* audio output */
+
+float t, tincr, tincr2;
+int16_t *samples;
+uint8_t *audio_outbuf;
+int audio_outbuf_size;
+int audio_input_frame_size;
+
+/*
+ * add an audio output stream
+ */
+static AVStream *add_audio_stream(AVFormatContext *oc, enum CodecID codec_id)
+{
+ AVCodecContext *c;
+ AVStream *st;
+
+ st = av_new_stream(oc, 1);
+ if (!st) {
+ fprintf(stderr, "Could not alloc stream\n");
+ exit(1);
+ }
+
+ c = st->codec;
+ c->codec_id = codec_id;
+ c->codec_type = AVMEDIA_TYPE_AUDIO;
+
+ /* put sample parameters */
+ c->sample_fmt = AV_SAMPLE_FMT_S16;
+ c->bit_rate = 64000;
+ c->sample_rate = 44100;
+ c->channels = 2;
+
+ // some formats want stream headers to be separate
+ if(oc->oformat->flags & AVFMT_GLOBALHEADER)
+ c->flags |= CODEC_FLAG_GLOBAL_HEADER;
+
+ return st;
+}
+
+static void open_audio(AVFormatContext *oc, AVStream *st)
+{
+ AVCodecContext *c;
+ AVCodec *codec;
+
+ c = st->codec;
+
+ /* find the audio encoder */
+ codec = avcodec_find_encoder(c->codec_id);
+ if (!codec) {
+ fprintf(stderr, "codec not found\n");
+ exit(1);
+ }
+
+ /* open it */
+ if (avcodec_open(c, codec) < 0) {
+ fprintf(stderr, "could not open codec\n");
+ exit(1);
+ }
+
+ /* init signal generator */
+ t = 0;
+ tincr = 2 * M_PI * 110.0 / c->sample_rate;
+ /* increment frequency by 110 Hz per second */
+ tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate;
+
+ audio_outbuf_size = 10000;
+ audio_outbuf = av_malloc(audio_outbuf_size);
+
+ /* ugly hack for PCM codecs (will be removed ASAP with new PCM
+ support to compute the input frame size in samples */
+ if (c->frame_size <= 1) {
+ audio_input_frame_size = audio_outbuf_size / c->channels;
+ switch(st->codec->codec_id) {
+ case CODEC_ID_PCM_S16LE:
+ case CODEC_ID_PCM_S16BE:
+ case CODEC_ID_PCM_U16LE:
+ case CODEC_ID_PCM_U16BE:
+ audio_input_frame_size >>= 1;
+ break;
+ default:
+ break;
+ }
+ } else {
+ audio_input_frame_size = c->frame_size;
+ }
+ samples = av_malloc(audio_input_frame_size * 2 * c->channels);
+}
+
+/* prepare a 16 bit dummy audio frame of 'frame_size' samples and
+ 'nb_channels' channels */
+static void get_audio_frame(int16_t *samples, int frame_size, int nb_channels)
+{
+ int j, i, v;
+ int16_t *q;
+
+ q = samples;
+ for(j=0;j<frame_size;j++) {
+ v = (int)(sin(t) * 10000);
+ for(i = 0; i < nb_channels; i++)
+ *q++ = v;
+ t += tincr;
+ tincr += tincr2;
+ }
+}
+
+static void write_audio_frame(AVFormatContext *oc, AVStream *st)
+{
+ AVCodecContext *c;
+ AVPacket pkt;
+ av_init_packet(&pkt);
+
+ c = st->codec;
+
+ get_audio_frame(samples, audio_input_frame_size, c->channels);
+
+ pkt.size= avcodec_encode_audio(c, audio_outbuf, audio_outbuf_size, samples);
+
+ if (c->coded_frame && c->coded_frame->pts != AV_NOPTS_VALUE)
+ pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);
+ pkt.flags |= AV_PKT_FLAG_KEY;
+ pkt.stream_index= st->index;
+ pkt.data= audio_outbuf;
+
+ /* write the compressed frame in the media file */
+ if (av_interleaved_write_frame(oc, &pkt) != 0) {
+ fprintf(stderr, "Error while writing audio frame\n");
+ exit(1);
+ }
+}
+
+static void close_audio(AVFormatContext *oc, AVStream *st)
+{
+ avcodec_close(st->codec);
+
+ av_free(samples);
+ av_free(audio_outbuf);
+}
+
+/**************************************************************/
+/* video output */
+
+AVFrame *picture, *tmp_picture;
+uint8_t *video_outbuf;
+int frame_count, video_outbuf_size;
+
+/* add a video output stream */
+static AVStream *add_video_stream(AVFormatContext *oc, enum CodecID codec_id)
+{
+ AVCodecContext *c;
+ AVStream *st;
+
+ st = av_new_stream(oc, 0);
+ if (!st) {
+ fprintf(stderr, "Could not alloc stream\n");
+ exit(1);
+ }
+
+ c = st->codec;
+ c->codec_id = codec_id;
+ c->codec_type = AVMEDIA_TYPE_VIDEO;
+
+ /* put sample parameters */
+ c->bit_rate = 400000;
+ /* resolution must be a multiple of two */
+ c->width = 352;
+ c->height = 288;
+ /* time base: 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
+ identically 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 == CODEC_ID_MPEG2VIDEO) {
+ /* just for testing, we also add B frames */
+ c->max_b_frames = 2;
+ }
+ if (c->codec_id == 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;
+ }
+ // some formats want stream headers to be separate
+ if(oc->oformat->flags & AVFMT_GLOBALHEADER)
+ c->flags |= CODEC_FLAG_GLOBAL_HEADER;
+
+ return st;
+}
+
+static AVFrame *alloc_picture(enum PixelFormat pix_fmt, int width, int height)
+{
+ AVFrame *picture;
+ uint8_t *picture_buf;
+ int size;
+
+ picture = avcodec_alloc_frame();
+ if (!picture)
+ return NULL;
+ size = avpicture_get_size(pix_fmt, width, height);
+ picture_buf = av_malloc(size);
+ if (!picture_buf) {
+ av_free(picture);
+ return NULL;
+ }
+ avpicture_fill((AVPicture *)picture, picture_buf,
+ pix_fmt, width, height);
+ return picture;
+}
+
+static void open_video(AVFormatContext *oc, AVStream *st)
+{
+ AVCodec *codec;
+ AVCodecContext *c;
+
+ c = st->codec;
+
+ /* find the video encoder */
+ codec = avcodec_find_encoder(c->codec_id);
+ if (!codec) {
+ fprintf(stderr, "codec not found\n");
+ exit(1);
+ }
+
+ /* open the codec */
+ if (avcodec_open(c, codec) < 0) {
+ fprintf(stderr, "could not open codec\n");
+ exit(1);
+ }
+
+ video_outbuf = NULL;
+ if (!(oc->oformat->flags & AVFMT_RAWPICTURE)) {
+ /* allocate output buffer */
+ /* XXX: API change will be done */
+ /* buffers passed into lav* can be allocated any way you prefer,
+ as long as they're aligned enough for the architecture, and
+ they're freed appropriately (such as using av_free for buffers
+ allocated with av_malloc) */
+ video_outbuf_size = 200000;
+ video_outbuf = av_malloc(video_outbuf_size);
+ }
+
+ /* allocate the encoded raw picture */
+ picture = alloc_picture(c->pix_fmt, c->width, c->height);
+ if (!picture) {
+ fprintf(stderr, "Could not allocate picture\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 */
+ tmp_picture = NULL;
+ if (c->pix_fmt != PIX_FMT_YUV420P) {
+ tmp_picture = alloc_picture(PIX_FMT_YUV420P, c->width, c->height);
+ if (!tmp_picture) {
+ 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;
+
+ 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 void write_video_frame(AVFormatContext *oc, AVStream *st)
+{
+ int out_size, ret;
+ AVCodecContext *c;
+ static struct SwsContext *img_convert_ctx;
+
+ c = st->codec;
+
+ if (frame_count >= STREAM_NB_FRAMES) {
+ /* no more frame to compress. The codec has a latency of a few
+ frames if using B frames, so we get the last frames by
+ passing the same picture again */
+ } else {
+ if (c->pix_fmt != PIX_FMT_YUV420P) {
+ /* as we only generate a YUV420P picture, we must convert it
+ to the codec pixel format if needed */
+ if (img_convert_ctx == NULL) {
+ img_convert_ctx = sws_getContext(c->width, c->height,
+ PIX_FMT_YUV420P,
+ c->width, c->height,
+ c->pix_fmt,
+ sws_flags, NULL, NULL, NULL);
+ if (img_convert_ctx == NULL) {
+ fprintf(stderr, "Cannot initialize the conversion context\n");
+ exit(1);
+ }
+ }
+ fill_yuv_image(tmp_picture, frame_count, c->width, c->height);
+ sws_scale(img_convert_ctx, tmp_picture->data, tmp_picture->linesize,
+ 0, c->height, picture->data, picture->linesize);
+ } else {
+ fill_yuv_image(picture, frame_count, c->width, c->height);
+ }
+ }
+
+
+ if (oc->oformat->flags & AVFMT_RAWPICTURE) {
+ /* raw video case. The API will change slightly in the near
+ futur for that */
+ AVPacket pkt;
+ av_init_packet(&pkt);
+
+ pkt.flags |= AV_PKT_FLAG_KEY;
+ pkt.stream_index= st->index;
+ pkt.data= (uint8_t *)picture;
+ pkt.size= sizeof(AVPicture);
+
+ ret = av_interleaved_write_frame(oc, &pkt);
+ } else {
+ /* encode the image */
+ out_size = avcodec_encode_video(c, video_outbuf, video_outbuf_size, picture);
+ /* if zero size, it means the image was buffered */
+ if (out_size > 0) {
+ AVPacket pkt;
+ av_init_packet(&pkt);
+
+ if (c->coded_frame->pts != AV_NOPTS_VALUE)
+ pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);
+ if(c->coded_frame->key_frame)
+ pkt.flags |= AV_PKT_FLAG_KEY;
+ pkt.stream_index= st->index;
+ pkt.data= video_outbuf;
+ pkt.size= out_size;
+
+ /* write the compressed frame in the media file */
+ ret = av_interleaved_write_frame(oc, &pkt);
+ } else {
+ ret = 0;
+ }
+ }
+ if (ret != 0) {
+ fprintf(stderr, "Error while writing video frame\n");
+ exit(1);
+ }
+ frame_count++;
+}
+
+static void close_video(AVFormatContext *oc, AVStream *st)
+{
+ avcodec_close(st->codec);
+ av_free(picture->data[0]);
+ av_free(picture);
+ if (tmp_picture) {
+ av_free(tmp_picture->data[0]);
+ av_free(tmp_picture);
+ }
+ av_free(video_outbuf);
+}
+
+/**************************************************************/
+/* media file output */
+
+int main(int argc, char **argv)
+{
+ const char *filename;
+ AVOutputFormat *fmt;
+ AVFormatContext *oc;
+ AVStream *audio_st, *video_st;
+ double audio_pts, video_pts;
+ int i;
+
+ /* 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"
+ "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]);
+ exit(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) {
+ exit(1);
+ }
+ fmt= oc->oformat;
+
+ /* add the audio and video streams using the default format codecs
+ and initialize the codecs */
+ video_st = NULL;
+ audio_st = NULL;
+ if (fmt->video_codec != CODEC_ID_NONE) {
+ video_st = add_video_stream(oc, fmt->video_codec);
+ }
+ if (fmt->audio_codec != CODEC_ID_NONE) {
+ audio_st = add_audio_stream(oc, fmt->audio_codec);
+ }
+
+ av_dump_format(oc, 0, filename, 1);
+
+ /* now that all the parameters are set, we can open the audio and
+ video codecs and allocate the necessary encode buffers */
+ if (video_st)
+ open_video(oc, video_st);
+ if (audio_st)
+ open_audio(oc, audio_st);
+
+ /* open the output file, if needed */
+ if (!(fmt->flags & AVFMT_NOFILE)) {
+ if (avio_open(&oc->pb, filename, AVIO_FLAG_WRITE) < 0) {
+ fprintf(stderr, "Could not open '%s'\n", filename);
+ exit(1);
+ }
+ }
+
+ /* write the stream header, if any */
+ av_write_header(oc);
+
+ for(;;) {
+ /* compute current audio and video time */
+ if (audio_st)
+ audio_pts = (double)audio_st->pts.val * audio_st->time_base.num / audio_st->time_base.den;
+ else
+ audio_pts = 0.0;
+
+ if (video_st)
+ video_pts = (double)video_st->pts.val * video_st->time_base.num / video_st->time_base.den;
+ else
+ video_pts = 0.0;
+
+ if ((!audio_st || audio_pts >= STREAM_DURATION) &&
+ (!video_st || video_pts >= STREAM_DURATION))
+ break;
+
+ /* write interleaved audio and video frames */
+ if (!video_st || (video_st && audio_st && audio_pts < video_pts)) {
+ write_audio_frame(oc, audio_st);
+ } else {
+ write_video_frame(oc, video_st);
+ }
+ }
+
+ /* write the trailer, if any. the trailer must be written
+ * before you close the CodecContexts open when you wrote the
+ * header; otherwise write_trailer may try to use memory that
+ * was freed on av_codec_close() */
+ av_write_trailer(oc);
+
+ /* close each codec */
+ if (video_st)
+ close_video(oc, video_st);
+ if (audio_st)
+ close_audio(oc, audio_st);
+
+ /* free the streams */
+ for(i = 0; i < oc->nb_streams; i++) {
+ av_freep(&oc->streams[i]->codec);
+ av_freep(&oc->streams[i]);
+ }
+
+ if (!(fmt->flags & AVFMT_NOFILE)) {
+ /* close the output file */
+ avio_close(oc->pb);
+ }
+
+ /* free the stream */
+ av_free(oc);
+
+ return 0;
+}