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-rw-r--r--doc/examples/avcodec.c339
1 files changed, 204 insertions, 135 deletions
diff --git a/doc/examples/avcodec.c b/doc/examples/avcodec.c
index 1478881c25..86727a7b48 100644
--- a/doc/examples/avcodec.c
+++ b/doc/examples/avcodec.c
@@ -1,21 +1,23 @@
/*
- * copyright (c) 2001 Fabrice Bellard
+ * Copyright (c) 2001 Fabrice Bellard
*
- * This file is part of Libav.
+ * 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:
*
- * Libav 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.
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
*
- * Libav 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 Libav; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ * 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.
*/
/**
@@ -23,25 +25,20 @@
* libavcodec API use example.
*
* @example avcodec.c
- * Note that this library only handles codecs (mpeg, mpeg4, etc...),
- * not file formats (avi, vob, etc...). See library 'libavformat' for the
+ * Note that libavcodec only handles codecs (mpeg, mpeg4, etc...),
+ * not file formats (avi, vob, mp4, mov, mkv, mxf, flv, mpegts, mpegps, 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 <math.h>
-#include "libavcodec/avcodec.h"
-#include "libavutil/channel_layout.h"
-#include "libavutil/common.h"
-#include "libavutil/imgutils.h"
-#include "libavutil/mathematics.h"
-#include "libavutil/samplefmt.h"
+#include <libavutil/opt.h>
+#include <libavcodec/avcodec.h>
+#include <libavutil/channel_layout.h>
+#include <libavutil/common.h>
+#include <libavutil/imgutils.h>
+#include <libavutil/mathematics.h>
+#include <libavutil/samplefmt.h>
#define INBUF_SIZE 4096
#define AUDIO_INBUF_SIZE 20480
@@ -115,16 +112,20 @@ static void audio_encode_example(const char *filename)
uint16_t *samples;
float t, tincr;
- printf("Audio encoding\n");
+ printf("Encode audio file %s\n", filename);
/* find the MP2 encoder */
codec = avcodec_find_encoder(AV_CODEC_ID_MP2);
if (!codec) {
- fprintf(stderr, "codec not found\n");
+ fprintf(stderr, "Codec not found\n");
exit(1);
}
c = avcodec_alloc_context3(codec);
+ if (!c) {
+ fprintf(stderr, "Could not allocate audio codec context\n");
+ exit(1);
+ }
/* put sample parameters */
c->bit_rate = 64000;
@@ -132,7 +133,7 @@ static void audio_encode_example(const char *filename)
/* check that the encoder supports s16 pcm input */
c->sample_fmt = AV_SAMPLE_FMT_S16;
if (!check_sample_fmt(codec, c->sample_fmt)) {
- fprintf(stderr, "encoder does not support %s",
+ fprintf(stderr, "Encoder does not support sample format %s",
av_get_sample_fmt_name(c->sample_fmt));
exit(1);
}
@@ -144,20 +145,20 @@ static void audio_encode_example(const char *filename)
/* open it */
if (avcodec_open2(c, codec, NULL) < 0) {
- fprintf(stderr, "could not open codec\n");
+ fprintf(stderr, "Could not open codec\n");
exit(1);
}
f = fopen(filename, "wb");
if (!f) {
- fprintf(stderr, "could not open %s\n", filename);
+ fprintf(stderr, "Could not open %s\n", filename);
exit(1);
}
/* frame containing input raw audio */
frame = av_frame_alloc();
if (!frame) {
- fprintf(stderr, "could not allocate audio frame\n");
+ fprintf(stderr, "Could not allocate audio frame\n");
exit(1);
}
@@ -169,9 +170,13 @@ static void audio_encode_example(const char *filename)
* we calculate the size of the samples buffer in bytes */
buffer_size = av_samples_get_buffer_size(NULL, c->channels, c->frame_size,
c->sample_fmt, 0);
+ if (buffer_size < 0) {
+ fprintf(stderr, "Could not get sample buffer size\n");
+ exit(1);
+ }
samples = av_malloc(buffer_size);
if (!samples) {
- fprintf(stderr, "could not allocate %d bytes for samples buffer\n",
+ fprintf(stderr, "Could not allocate %d bytes for samples buffer\n",
buffer_size);
exit(1);
}
@@ -179,14 +184,14 @@ static void audio_encode_example(const char *filename)
ret = avcodec_fill_audio_frame(frame, c->channels, c->sample_fmt,
(const uint8_t*)samples, buffer_size, 0);
if (ret < 0) {
- fprintf(stderr, "could not setup audio frame\n");
+ fprintf(stderr, "Could not setup audio frame\n");
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 (i = 0; i < 200; i++) {
av_init_packet(&pkt);
pkt.data = NULL; // packet data will be allocated by the encoder
pkt.size = 0;
@@ -201,9 +206,23 @@ static void audio_encode_example(const char *filename)
/* encode the samples */
ret = avcodec_encode_audio2(c, &pkt, frame, &got_output);
if (ret < 0) {
- fprintf(stderr, "error encoding audio frame\n");
+ fprintf(stderr, "Error encoding audio frame\n");
+ exit(1);
+ }
+ if (got_output) {
+ fwrite(pkt.data, 1, pkt.size, f);
+ av_free_packet(&pkt);
+ }
+ }
+
+ /* get the delayed frames */
+ for (got_output = 1; got_output; i++) {
+ ret = avcodec_encode_audio2(c, &pkt, NULL, &got_output);
+ if (ret < 0) {
+ fprintf(stderr, "Error encoding frame\n");
exit(1);
}
+
if (got_output) {
fwrite(pkt.data, 1, pkt.size, f);
av_free_packet(&pkt);
@@ -232,26 +251,30 @@ static void audio_decode_example(const char *outfilename, const char *filename)
av_init_packet(&avpkt);
- printf("Audio decoding\n");
+ printf("Decode audio file %s to %s\n", filename, outfilename);
/* find the mpeg audio decoder */
codec = avcodec_find_decoder(AV_CODEC_ID_MP2);
if (!codec) {
- fprintf(stderr, "codec not found\n");
+ fprintf(stderr, "Codec not found\n");
exit(1);
}
c = avcodec_alloc_context3(codec);
+ if (!c) {
+ fprintf(stderr, "Could not allocate audio codec context\n");
+ exit(1);
+ }
/* open it */
if (avcodec_open2(c, codec, NULL) < 0) {
- fprintf(stderr, "could not open codec\n");
+ fprintf(stderr, "Could not open codec\n");
exit(1);
}
f = fopen(filename, "rb");
if (!f) {
- fprintf(stderr, "could not open %s\n", filename);
+ fprintf(stderr, "Could not open %s\n", filename);
exit(1);
}
outfile = fopen(outfilename, "wb");
@@ -269,7 +292,7 @@ static void audio_decode_example(const char *outfilename, const char *filename)
if (!decoded_frame) {
if (!(decoded_frame = av_frame_alloc())) {
- fprintf(stderr, "out of memory\n");
+ fprintf(stderr, "Could not allocate audio frame\n");
exit(1);
}
}
@@ -284,10 +307,17 @@ static void audio_decode_example(const char *outfilename, const char *filename)
int data_size = av_samples_get_buffer_size(NULL, c->channels,
decoded_frame->nb_samples,
c->sample_fmt, 1);
+ if (data_size < 0) {
+ /* This should not occur, checking just for paranoia */
+ fprintf(stderr, "Failed to calculate data size\n");
+ exit(1);
+ }
fwrite(decoded_frame->data[0], 1, data_size, outfile);
}
avpkt.size -= len;
avpkt.data += len;
+ avpkt.dts =
+ avpkt.pts = AV_NOPTS_VALUE;
if (avpkt.size < AUDIO_REFILL_THRESH) {
/* Refill the input buffer, to avoid trying to decode
* incomplete frames. Instead of this, one could also use
@@ -313,27 +343,30 @@ static void audio_decode_example(const char *outfilename, const char *filename)
/*
* Video encoding example
*/
-static void video_encode_example(const char *filename)
+static void video_encode_example(const char *filename, int codec_id)
{
AVCodec *codec;
AVCodecContext *c= NULL;
int i, ret, x, y, got_output;
FILE *f;
- AVFrame *picture;
+ AVFrame *frame;
AVPacket pkt;
uint8_t endcode[] = { 0, 0, 1, 0xb7 };
- printf("Video encoding\n");
+ printf("Encode video file %s\n", filename);
/* find the mpeg1 video encoder */
- codec = avcodec_find_encoder(AV_CODEC_ID_MPEG1VIDEO);
+ codec = avcodec_find_encoder(codec_id);
if (!codec) {
- fprintf(stderr, "codec not found\n");
+ fprintf(stderr, "Codec not found\n");
exit(1);
}
c = avcodec_alloc_context3(codec);
- picture = av_frame_alloc();
+ if (!c) {
+ fprintf(stderr, "Could not allocate video codec context\n");
+ exit(1);
+ }
/* put sample parameters */
c->bit_rate = 400000;
@@ -341,35 +374,52 @@ static void video_encode_example(const char *filename)
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->time_base = (AVRational){1,25};
+ /* emit one intra frame every ten frames
+ * check frame pict_type before passing frame
+ * to encoder, if frame->pict_type is AV_PICTURE_TYPE_I
+ * then gop_size is ignored and the output of encoder
+ * will always be I frame irrespective to gop_size
+ */
+ c->gop_size = 10;
+ c->max_b_frames = 1;
c->pix_fmt = AV_PIX_FMT_YUV420P;
+ if (codec_id == AV_CODEC_ID_H264)
+ av_opt_set(c->priv_data, "preset", "slow", 0);
+
/* open it */
if (avcodec_open2(c, codec, NULL) < 0) {
- fprintf(stderr, "could not open codec\n");
+ fprintf(stderr, "Could not open codec\n");
exit(1);
}
f = fopen(filename, "wb");
if (!f) {
- fprintf(stderr, "could not open %s\n", filename);
+ fprintf(stderr, "Could not open %s\n", filename);
+ exit(1);
+ }
+
+ frame = av_frame_alloc();
+ if (!frame) {
+ fprintf(stderr, "Could not allocate video frame\n");
exit(1);
}
+ frame->format = c->pix_fmt;
+ frame->width = c->width;
+ frame->height = c->height;
- ret = av_image_alloc(picture->data, picture->linesize, c->width, c->height,
+ /* the image can be allocated by any means and av_image_alloc() is
+ * just the most convenient way if av_malloc() is to be used */
+ ret = av_image_alloc(frame->data, frame->linesize, c->width, c->height,
c->pix_fmt, 32);
if (ret < 0) {
- fprintf(stderr, "could not alloc raw picture buffer\n");
+ fprintf(stderr, "Could not allocate raw picture buffer\n");
exit(1);
}
- picture->format = c->pix_fmt;
- picture->width = c->width;
- picture->height = c->height;
/* encode 1 second of video */
- for(i=0;i<25;i++) {
+ for (i = 0; i < 25; i++) {
av_init_packet(&pkt);
pkt.data = NULL; // packet data will be allocated by the encoder
pkt.size = 0;
@@ -377,31 +427,31 @@ static void video_encode_example(const char *filename)
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;
+ for (y = 0; y < c->height; y++) {
+ for (x = 0; x < c->width; x++) {
+ frame->data[0][y * frame->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;
+ for (y = 0; y < c->height/2; y++) {
+ for (x = 0; x < c->width/2; x++) {
+ frame->data[1][y * frame->linesize[1] + x] = 128 + y + i * 2;
+ frame->data[2][y * frame->linesize[2] + x] = 64 + x + i * 5;
}
}
- picture->pts = i;
+ frame->pts = i;
/* encode the image */
- ret = avcodec_encode_video2(c, &pkt, picture, &got_output);
+ ret = avcodec_encode_video2(c, &pkt, frame, &got_output);
if (ret < 0) {
- fprintf(stderr, "error encoding frame\n");
+ fprintf(stderr, "Error encoding frame\n");
exit(1);
}
if (got_output) {
- printf("encoding frame %3d (size=%5d)\n", i, pkt.size);
+ printf("Write frame %3d (size=%5d)\n", i, pkt.size);
fwrite(pkt.data, 1, pkt.size, f);
av_free_packet(&pkt);
}
@@ -413,12 +463,12 @@ static void video_encode_example(const char *filename)
ret = avcodec_encode_video2(c, &pkt, NULL, &got_output);
if (ret < 0) {
- fprintf(stderr, "error encoding frame\n");
+ fprintf(stderr, "Error encoding frame\n");
exit(1);
}
if (got_output) {
- printf("encoding frame %3d (size=%5d)\n", i, pkt.size);
+ printf("Write frame %3d (size=%5d)\n", i, pkt.size);
fwrite(pkt.data, 1, pkt.size, f);
av_free_packet(&pkt);
}
@@ -430,8 +480,8 @@ static void video_encode_example(const char *filename)
avcodec_close(c);
av_free(c);
- av_freep(&picture->data[0]);
- av_frame_free(&picture);
+ av_freep(&frame->data[0]);
+ av_frame_free(&frame);
printf("\n");
}
@@ -445,22 +495,49 @@ static void pgm_save(unsigned char *buf, int wrap, int xsize, int ysize,
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);
+ 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 int decode_write_frame(const char *outfilename, AVCodecContext *avctx,
+ AVFrame *frame, int *frame_count, AVPacket *pkt, int last)
+{
+ int len, got_frame;
+ char buf[1024];
+
+ len = avcodec_decode_video2(avctx, frame, &got_frame, pkt);
+ if (len < 0) {
+ fprintf(stderr, "Error while decoding frame %d\n", *frame_count);
+ return len;
+ }
+ if (got_frame) {
+ printf("Saving %sframe %3d\n", last ? "last " : "", *frame_count);
+ fflush(stdout);
+
+ /* the picture is allocated by the decoder, no need to free it */
+ snprintf(buf, sizeof(buf), outfilename, *frame_count);
+ pgm_save(frame->data[0], frame->linesize[0],
+ avctx->width, avctx->height, buf);
+ (*frame_count)++;
+ }
+ if (pkt->data) {
+ pkt->size -= len;
+ pkt->data += len;
+ }
+ return 0;
+}
+
static void video_decode_example(const char *outfilename, const char *filename)
{
AVCodec *codec;
AVCodecContext *c= NULL;
- int frame, got_picture, len;
+ int frame_count;
FILE *f;
- AVFrame *picture;
+ AVFrame *frame;
uint8_t inbuf[INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE];
- char buf[1024];
AVPacket avpkt;
av_init_packet(&avpkt);
@@ -468,17 +545,20 @@ static void video_decode_example(const char *outfilename, const char *filename)
/* 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");
+ printf("Decode video file %s to %s\n", filename, outfilename);
/* find the mpeg1 video decoder */
codec = avcodec_find_decoder(AV_CODEC_ID_MPEG1VIDEO);
if (!codec) {
- fprintf(stderr, "codec not found\n");
+ fprintf(stderr, "Codec not found\n");
exit(1);
}
c = avcodec_alloc_context3(codec);
- picture = av_frame_alloc();
+ if (!c) {
+ fprintf(stderr, "Could not allocate video codec context\n");
+ exit(1);
+ }
if(codec->capabilities&CODEC_CAP_TRUNCATED)
c->flags|= CODEC_FLAG_TRUNCATED; /* we do not send complete frames */
@@ -489,20 +569,24 @@ static void video_decode_example(const char *outfilename, const char *filename)
/* open it */
if (avcodec_open2(c, codec, NULL) < 0) {
- fprintf(stderr, "could not open codec\n");
+ 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);
+ fprintf(stderr, "Could not open %s\n", filename);
exit(1);
}
- frame = 0;
- for(;;) {
+ frame = av_frame_alloc();
+ if (!frame) {
+ fprintf(stderr, "Could not allocate video frame\n");
+ exit(1);
+ }
+
+ frame_count = 0;
+ for (;;) {
avpkt.size = fread(inbuf, 1, INBUF_SIZE, f);
if (avpkt.size == 0)
break;
@@ -523,26 +607,9 @@ static void video_decode_example(const char *outfilename, const char *filename)
/* 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);
+ while (avpkt.size > 0)
+ if (decode_write_frame(outfilename, c, frame, &frame_count, &avpkt, 0) < 0)
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
@@ -550,46 +617,48 @@ static void video_decode_example(const char *outfilename, const char *filename)
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++;
- }
+ decode_write_frame(outfilename, c, frame, &frame_count, &avpkt, 1);
fclose(f);
avcodec_close(c);
av_free(c);
- av_frame_free(&picture);
+ av_frame_free(&frame);
printf("\n");
}
int main(int argc, char **argv)
{
- const char *filename;
+ const char *output_type;
/* 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";
+ if (argc < 2) {
+ printf("usage: %s output_type\n"
+ "API example program to decode/encode a media stream with libavcodec.\n"
+ "This program generates a synthetic stream and encodes it to a file\n"
+ "named test.h264, test.mp2 or test.mpg depending on output_type.\n"
+ "The encoded stream is then decoded and written to a raw data output.\n"
+ "output_type must be choosen between 'h264', 'mp2', 'mpg'.\n",
+ argv[0]);
+ return 1;
+ }
+ output_type = argv[1];
+
+ if (!strcmp(output_type, "h264")) {
+ video_encode_example("test.h264", AV_CODEC_ID_H264);
+ } else if (!strcmp(output_type, "mp2")) {
+ audio_encode_example("test.mp2");
+ audio_decode_example("test.sw", "test.mp2");
+ } else if (!strcmp(output_type, "mpg")) {
+ video_encode_example("test.mpg", AV_CODEC_ID_MPEG1VIDEO);
+ video_decode_example("test%02d.pgm", "test.mpg");
} else {
- filename = argv[1];
+ fprintf(stderr, "Invalid output type '%s', choose between 'h264', 'mp2', or 'mpg'\n",
+ output_type);
+ return 1;
}
- // audio_decode_example("/tmp/test.sw", filename);
- video_decode_example("/tmp/test%d.pgm", filename);
-
return 0;
}
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