[FFmpeg-cvslog] examples/avcodec: split audio decoding into a separate example
Anton Khirnov
git at videolan.org
Wed Mar 29 14:44:28 EEST 2017
ffmpeg | branch: master | Anton Khirnov <anton at khirnov.net> | Wed Oct 19 21:05:22 2016 +0200| [f5df897c4b61985e3afc89ba1290649712ff438e] | committer: Anton Khirnov
examples/avcodec: split audio decoding into a separate example
The four examples (audio/video encoding/decoding) are completely
independent so it makes little sense to have them all in one file.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f5df897c4b61985e3afc89ba1290649712ff438e
---
configure | 2 +
doc/Makefile | 4 +-
doc/examples/avcodec.c | 97 -------------------------------
doc/examples/decode_audio.c | 137 ++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 142 insertions(+), 98 deletions(-)
diff --git a/configure b/configure
index 28567bb..b19e3e1 100755
--- a/configure
+++ b/configure
@@ -1210,6 +1210,7 @@ COMPONENT_LIST="
EXAMPLE_LIST="
avcodec_example
+ decode_audio_example
encode_audio_example
filter_audio_example
metadata_example
@@ -2436,6 +2437,7 @@ scale_vaapi_filter_deps="vaapi VAProcPipelineParameterBuffer"
# examples
avcodec_example_deps="avcodec avutil"
+decode_audio_example_deps="avcodec avutil"
encode_audio_example_deps="avcodec avutil"
filter_audio_example_deps="avfilter avutil"
metadata_example_deps="avformat avutil"
diff --git a/doc/Makefile b/doc/Makefile
index 738e601..326bb12 100644
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -17,13 +17,15 @@ DOCS-$(CONFIG_TEXI2HTML) += $(HTMLPAGES)
DOCS = $(DOCS-yes)
DOC_EXAMPLES-$(CONFIG_AVCODEC_EXAMPLE) += avcodec
+DOC_EXAMPLES-$(CONFIG_DECODE_AUDIO_EXAMPLE) += decode_audio
DOC_EXAMPLES-$(CONFIG_ENCODE_AUDIO_EXAMPLE) += encode_audio
DOC_EXAMPLES-$(CONFIG_FILTER_AUDIO_EXAMPLE) += filter_audio
DOC_EXAMPLES-$(CONFIG_METADATA_EXAMPLE) += metadata
DOC_EXAMPLES-$(CONFIG_OUTPUT_EXAMPLE) += output
DOC_EXAMPLES-$(CONFIG_QSVDEC_EXAMPLE) += qsvdec
DOC_EXAMPLES-$(CONFIG_TRANSCODE_AAC_EXAMPLE) += transcode_aac
-ALL_DOC_EXAMPLES = avcodec encode_audio filter_audio metadata output transcode_aac
+ALL_DOC_EXAMPLES = avcodec decode_audio encode_audio filter_audio metadata \
+ output transcode_aac
DOC_EXAMPLES := $(DOC_EXAMPLES-yes:%=doc/examples/%$(EXESUF))
ALL_DOC_EXAMPLES := $(ALL_DOC_EXAMPLES:%=doc/examples/%$(EXESUF))
diff --git a/doc/examples/avcodec.c b/doc/examples/avcodec.c
index 63812d9..4f7dc8b 100644
--- a/doc/examples/avcodec.c
+++ b/doc/examples/avcodec.c
@@ -44,100 +44,6 @@
#include "libavutil/samplefmt.h"
#define INBUF_SIZE 4096
-#define AUDIO_INBUF_SIZE 20480
-#define AUDIO_REFILL_THRESH 4096
-
-/*
- * Audio decoding.
- */
-static void audio_decode_example(const char *outfilename, const char *filename)
-{
- AVCodec *codec;
- AVCodecContext *c= NULL;
- int len;
- FILE *f, *outfile;
- uint8_t inbuf[AUDIO_INBUF_SIZE + AV_INPUT_BUFFER_PADDING_SIZE];
- AVPacket avpkt;
- AVFrame *decoded_frame = NULL;
-
- av_init_packet(&avpkt);
-
- printf("Audio decoding\n");
-
- /* find the MPEG audio decoder */
- codec = avcodec_find_decoder(AV_CODEC_ID_MP2);
- if (!codec) {
- fprintf(stderr, "codec not found\n");
- exit(1);
- }
-
- c = avcodec_alloc_context3(codec);
-
- /* open it */
- if (avcodec_open2(c, codec, NULL) < 0) {
- fprintf(stderr, "could not open codec\n");
- exit(1);
- }
-
- 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) {
- int got_frame = 0;
-
- if (!decoded_frame) {
- if (!(decoded_frame = av_frame_alloc())) {
- fprintf(stderr, "out of memory\n");
- exit(1);
- }
- }
-
- len = avcodec_decode_audio4(c, decoded_frame, &got_frame, &avpkt);
- if (len < 0) {
- fprintf(stderr, "Error while decoding\n");
- exit(1);
- }
- if (got_frame) {
- /* if a frame has been decoded, output it */
- int data_size = av_samples_get_buffer_size(NULL, c->channels,
- decoded_frame->nb_samples,
- c->sample_fmt, 1);
- fwrite(decoded_frame->data[0], 1, data_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);
-
- avcodec_free_context(&c);
- av_frame_free(&decoded_frame);
-}
/*
* Video encoding example
@@ -406,15 +312,12 @@ int main(int argc, char **argv)
avcodec_register_all();
if (argc <= 1) {
- 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/decode_audio.c b/doc/examples/decode_audio.c
new file mode 100644
index 0000000..4378281
--- /dev/null
+++ b/doc/examples/decode_audio.c
@@ -0,0 +1,137 @@
+/*
+ * copyright (c) 2001 Fabrice Bellard
+ *
+ * This file is part of Libav.
+ *
+ * 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.
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * audio decoding with libavcodec API example
+ *
+ * @example decode_audio.c
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "libavcodec/avcodec.h"
+
+#include "libavutil/frame.h"
+
+#define AUDIO_INBUF_SIZE 20480
+#define AUDIO_REFILL_THRESH 4096
+
+int main(int argc, char **argv)
+{
+ const char *outfilename, *filename;
+ AVCodec *codec;
+ AVCodecContext *c= NULL;
+ int len;
+ FILE *f, *outfile;
+ uint8_t inbuf[AUDIO_INBUF_SIZE + AV_INPUT_BUFFER_PADDING_SIZE];
+ AVPacket avpkt;
+ AVFrame *decoded_frame = NULL;
+
+ if (argc <= 2) {
+ fprintf(stderr, "Usage: %s <input file> <output file>\n", argv[0]);
+ exit(0);
+ }
+ filename = argv[1];
+ outfilename = argv[2];
+
+ /* register all the codecs */
+ avcodec_register_all();
+
+ av_init_packet(&avpkt);
+
+ /* find the MPEG audio decoder */
+ codec = avcodec_find_decoder(AV_CODEC_ID_MP2);
+ if (!codec) {
+ fprintf(stderr, "codec not found\n");
+ exit(1);
+ }
+
+ c = avcodec_alloc_context3(codec);
+
+ /* open it */
+ if (avcodec_open2(c, codec, NULL) < 0) {
+ fprintf(stderr, "could not open codec\n");
+ exit(1);
+ }
+
+ 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) {
+ int got_frame = 0;
+
+ if (!decoded_frame) {
+ if (!(decoded_frame = av_frame_alloc())) {
+ fprintf(stderr, "out of memory\n");
+ exit(1);
+ }
+ }
+
+ len = avcodec_decode_audio4(c, decoded_frame, &got_frame, &avpkt);
+ if (len < 0) {
+ fprintf(stderr, "Error while decoding\n");
+ exit(1);
+ }
+ if (got_frame) {
+ /* if a frame has been decoded, output it */
+ int data_size = av_samples_get_buffer_size(NULL, c->channels,
+ decoded_frame->nb_samples,
+ c->sample_fmt, 1);
+ fwrite(decoded_frame->data[0], 1, data_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);
+
+ avcodec_free_context(&c);
+ av_frame_free(&decoded_frame);
+
+ return 0;
+}
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