[SCM] libav/experimental: long awaited simple libavformat output API example
siretart at users.alioth.debian.org
siretart at users.alioth.debian.org
Sun Jun 30 15:36:54 UTC 2013
The following commit has been merged in the experimental branch:
commit 8de65d4f1170e81da42060689bba8fedc184ddf5
Author: Fabrice Bellard <fabrice at bellard.org>
Date: Tue Jul 22 12:46:15 2003 +0000
long awaited simple libavformat output API example
Originally committed as revision 2069 to svn://svn.ffmpeg.org/ffmpeg/trunk
diff --git a/Makefile b/Makefile
index eb09916..35155bc 100644
--- a/Makefile
+++ b/Makefile
@@ -25,6 +25,7 @@ endif
endif
PROG=ffmpeg$(EXE)
+PROGTEST=output_example$(EXE)
ifeq ($(CONFIG_FFSERVER),yes)
PROG+=ffserver$(EXE)
@@ -75,7 +76,7 @@ OBJS = ffmpeg.o ffserver.o cmdutils.o ffplay.o
SRCS = $(OBJS:.o=.c) $(ASM_OBJS:.o=.s)
FFLIBS = -L./libavformat -lavformat -L./libavcodec -lavcodec
-all: lib $(PROG) $(VHOOK)
+all: lib $(PROG) $(PROGTEST) $(VHOOK)
lib: $(AMRLIBS)
$(MAKE) -C libavcodec all
@@ -98,6 +99,9 @@ ffplay$(EXE): ffplay_g$(EXE)
cp -p $< $@
$(STRIP) $@
+output_example$(EXE): output_example.o .libs
+ $(CC) $(LDFLAGS) -o $@ output_example.o $(FFLIBS) $(EXTRALIBS)
+
ffplay.o: ffplay.c
$(CC) $(CFLAGS) $(SDL_CFLAGS) -c -o $@ $<
diff --git a/output_example.c b/output_example.c
new file mode 100644
index 0000000..0786949
--- /dev/null
+++ b/output_example.c
@@ -0,0 +1,350 @@
+/*
+ * 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 <math.h>
+
+#include "avformat.h"
+
+/* 5 seconds stream duration */
+#define STREAM_DURATION 5.0
+
+
+/**************************************************************/
+/* audio output */
+
+float t, tincr;
+int16_t *samples;
+uint8_t *audio_outbuf;
+int audio_outbuf_size;
+int audio_input_frame_size;
+
+/*
+ * add an audio output stream
+ */
+AVStream *add_audio_stream(AVFormatContext *oc, int codec_id)
+{
+ AVCodec *codec;
+ AVCodecContext *c;
+ AVStream *st;
+
+ st = av_new_stream(oc, 1);
+ if (!st) {
+ fprintf(stderr, "Could not alloc stream\n");
+ exit(1);
+ }
+
+ /* find the MP2 encoder */
+ codec = avcodec_find_encoder(codec_id);
+ if (!codec) {
+ fprintf(stderr, "codec not found\n");
+ exit(1);
+ }
+ c = &st->codec;
+
+ avcodec_get_context_defaults(c);
+
+ c->codec_type = CODEC_TYPE_AUDIO;
+
+ /* 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);
+ }
+
+ /* init signal generator */
+ t = 0;
+ tincr = 2 * M_PI * 440.0 / c->sample_rate;
+
+ audio_outbuf_size = 10000;
+ audio_outbuf = 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 = malloc(audio_input_frame_size * 2 * c->channels);
+
+ return st;
+}
+
+void write_audio_frame(AVFormatContext *oc, AVStream *st)
+{
+ int j, out_size;
+ AVCodecContext *c;
+
+
+ c = &st->codec;
+
+ for(j=0;j<audio_input_frame_size;j++) {
+ samples[2*j] = (int)(sin(t) * 10000);
+ samples[2*j+1] = samples[2*j];
+ t += tincr;
+ }
+
+ out_size = avcodec_encode_audio(c, audio_outbuf, audio_outbuf_size, samples);
+
+ /* write the compressed frame in the media file */
+ if (av_write_frame(oc, st->index, audio_outbuf, out_size) != 0) {
+ fprintf(stderr, "Error while writing audio frame\n");
+ exit(1);
+ }
+}
+
+/**************************************************************/
+/* video output */
+
+AVFrame *picture;
+uint8_t *video_outbuf;
+int frame_count, video_outbuf_size;
+
+/* add a video output stream */
+AVStream *add_video_stream(AVFormatContext *oc, int codec_id)
+{
+ AVCodec *codec;
+ AVCodecContext *c;
+ AVStream *st;
+ uint8_t *picture_buf;
+ int size;
+
+ st = av_new_stream(oc, 0);
+ if (!st) {
+ fprintf(stderr, "Could not alloc stream\n");
+ exit(1);
+ }
+
+ /* find the mpeg1 video encoder */
+ codec = avcodec_find_encoder(codec_id);
+ if (!codec) {
+ fprintf(stderr, "codec not found\n");
+ exit(1);
+ }
+
+ c = &st->codec;
+
+ avcodec_get_context_defaults(c);
+
+ c->codec_type = CODEC_TYPE_VIDEO;
+
+ /* put sample parameters */
+ c->bit_rate = 400000;
+ /* resolution must be a multiple of two */
+ c->width = 352;
+ c->height = 288;
+ /* frames per second */
+ c->frame_rate = 25;
+ c->frame_rate_base= 1;
+ c->gop_size = 12; /* emit one intra frame every twelve frames */
+
+ /* open it */
+ if (avcodec_open(c, codec) < 0) {
+ fprintf(stderr, "could not open codec\n");
+ exit(1);
+ }
+
+ /* alloc various buffers */
+ picture= avcodec_alloc_frame();
+ video_outbuf_size = 100000;
+ video_outbuf = malloc(video_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;
+
+ return st;
+}
+
+void write_video_frame(AVFormatContext *oc, AVStream *st)
+{
+ int x, y, i, out_size;
+ AVCodecContext *c;
+
+ c = &st->codec;
+
+ /* prepare a dummy image */
+ /* Y */
+ i = frame_count++;
+ 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, video_outbuf, video_outbuf_size, picture);
+
+ /* write the compressed frame in the media file */
+ if (av_write_frame(oc, st->index, video_outbuf, out_size) != 0) {
+ fprintf(stderr, "Error while writing video frame\n");
+ exit(1);
+ }
+}
+
+/**************************************************************/
+/* media file output */
+
+int main(int argc, char **argv)
+{
+ const char *filename;
+ AVOutputFormat *fmt;
+ AVFormatContext *oc;
+ AVStream *st, *audio_st, *video_st;
+ int i;
+ double audio_pts, video_pts;
+
+ /* initialize libavcodec, and register all codecs and formats */
+ av_register_all();
+
+ if (argc != 2) {
+ printf("usage: %s output_file\n"
+ "API example program for to output media file with libavformat\n"
+ "\n", argv[0]);
+ exit(1);
+ }
+
+ filename = argv[1];
+
+ /* auto detect the output format from the name. default is
+ mpeg. */
+ fmt = guess_format(NULL, filename, NULL);
+ if (!fmt) {
+ printf("Could not deduce output format from file extension: using MPEG.\n");
+ fmt = guess_format("mpeg", NULL, NULL);
+ }
+ if (!fmt) {
+ fprintf(stderr, "Could not find suitable output format\n");
+ exit(1);
+ }
+
+ /* allocate the output media context */
+ oc = av_mallocz(sizeof(AVFormatContext));
+ if (!oc) {
+ fprintf(stderr, "Memory error\n");
+ exit(1);
+ }
+ oc->oformat = fmt;
+
+ /* 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);
+ }
+
+ dump_format(oc, 0, filename, 1);
+
+ /* open the output file, if needed */
+ if (!(fmt->flags & AVFMT_NOFILE)) {
+ if (url_fopen(&oc->pb, filename, URL_WRONLY) < 0) {
+ fprintf(stderr, "Could not open '%s'\n", filename);
+ exit(1);
+ }
+ }
+
+ /* set the output parameters (must be done even if no parameters) */
+ av_set_parameters(oc, NULL);
+
+ /* 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 * oc->pts_num / oc->pts_den;
+ else
+ audio_pts = 0.0;
+
+ if (video_st)
+ video_pts = (double)video_st->pts.val * oc->pts_num / oc->pts_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_pts < video_pts)) {
+ write_audio_frame(oc, audio_st);
+ } else {
+ write_video_frame(oc, video_st);
+ }
+ }
+
+ /* close each codec */
+ for(i = 0;i < oc->nb_streams; i++) {
+ st = oc->streams[i];
+ avcodec_close(&st->codec);
+ }
+
+ /* write the trailer, if any */
+ av_write_trailer(oc);
+
+ if (!(fmt->flags & AVFMT_NOFILE)) {
+ /* close the output file */
+ url_fclose(&oc->pb);
+ }
+
+ /* free the stream */
+ av_free(oc);
+
+ return 0;
+}
--
Libav/FFmpeg packaging
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