/*
* 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
* simple audio converter
*
* @example transcode_aac.c
* Convert an input audio file to AAC in an MP4 container using FFmpeg.
* @author Andreas Unterweger (dustsigns@gmail.com)
*/
#include <stdio.h>
#include "libavformat/avformat.h"
#include "libavformat/avio.h"
#include "libavcodec/avcodec.h"
#include "libavutil/audio_fifo.h"
#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/frame.h"
#include "libavutil/opt.h"
#include "libswresample/swresample.h"
/** The output bit rate in kbit/s */
#define OUTPUT_BIT_RATE 96000
/** The number of output channels */
#define OUTPUT_CHANNELS 2
/** Open an input file and the required decoder. */
static int open_input_file(const char *filename,
AVFormatContext **input_format_context,
AVCodecContext **input_codec_context)
{
AVCodecContext *avctx;
AVCodec *input_codec;
int error;
/** Open the input file to read from it. */
if ((error = avformat_open_input(input_format_context, filename, NULL,
NULL)) < 0) {
fprintf(stderr, "Could not open input file '%s' (error '%s')\n",
filename, av_err2str(error));
*input_format_context = NULL;
return error;
}
/** Get information on the input file (number of streams etc.). */
if ((error = avformat_find_stream_info(*input_format_context, NULL)) < 0) {
fprintf(stderr, "Could not open find stream info (error '%s')\n",
av_err2str(error));
avformat_close_input(input_format_context);
return error;
}
/** Make sure that there is only one stream in the input file. */
if ((*input_format_context)->nb_streams != 1) {
fprintf(stderr, "Expected one audio input stream, but found %d\n",
(*input_format_context)->nb_streams);
avformat_close_input(input_format_context);
return AVERROR_EXIT;
}
/** Find a decoder for the audio stream. */
if (!(input_codec = avcodec_find_decoder((*input_format_context)->streams[0]->codecpar->codec_id))) {
fprintf(stderr, "Could not find input codec\n");
avformat_close_input(input_format_context);
return AVERROR_EXIT;
}
/** allocate a new decoding context */
avctx = avcodec_alloc_context3(input_codec);
if (!avctx) {
fprintf(stderr, "Could not allocate a decoding context\n");
avformat_close_input(input_format_context);
return AVERROR(ENOMEM);
}
/** initialize the stream parameters with demuxer information */
error = avcodec_parameters_to_context(avctx, (*input_format_context)->streams[0]->codecpar);
if (error < 0) {
avformat_close_input(input_format_context);
avcodec_free_context(&avctx);
return error;
}
/** Open the decoder for the audio stream to use it later. */
if ((error = avcodec_open2(avctx, input_codec, NULL)) < 0) {
fprintf(stderr, "Could not open input codec (error '%s')\n",
av_err2str(error));
avcodec_free_context(&avctx);
avformat_close_input(input_format_context);
return error;
}
/** Save the decoder context for easier access later. */
*input_codec_context = avctx;
return 0;
}
/**
* Open an output file and the required encoder.
* Also set some basic encoder parameters.
* Some of these parameters are based on the input file's parameters.
*/
static int open_output_file(const char *filename,
AVCodecContext *input_codec_context,
AVFormatContext **output_format_context,
AVCodecContext **output_codec_context)
{
AVCodecContext *avctx = NULL;
AVIOContext *output_io_context = NULL;
AVStream *stream = NULL;
AVCodec *output_codec = NULL;
int error;
/** Open the output file to write to it. */
if ((error = avio_open(&output_io_context, filename,
AVIO_FLAG_WRITE)) < 0) {
fprintf(stderr, "Could not open output file '%s' (error '%s')\n",
filename, av_err2str(error));
return error;
}
/** Create a new format context for the output container format. */
if (!(*output_format_context = avformat_alloc_context())) {
fprintf(stderr, "Could not allocate output format context\n");
return AVERROR(ENOMEM);
}
/** Associate the output file (pointer) with the container format context. */
(*output_format_context)->pb = output_io_context;
/** Guess the desired container format based on the file extension. */
if (!((*output_format_context)->oformat = av_guess_format(NULL, filename,
NULL))) {
fprintf(stderr, "Could not find output file format\n");
goto cleanup;
}
av_strlcpy((*output_format_context)->filename, filename,
sizeof((*output_format_context)->filename));
/** Find the encoder to be used by its name. */
if (!(output_codec = avcodec_find_encoder(AV_CODEC_ID_AAC))) {
fprintf(stderr, "Could not find an AAC encoder.\n");
goto cleanup;
}
/** Create a new audio stream in the output file container. */
if (!(stream = avformat_new_stream(*output_format_context, NULL))) {
fprintf(stderr, "Could not create new stream\n");
error = AVERROR(ENOMEM);
goto cleanup;
}
avctx = avcodec_alloc_context3(output_codec);
if (!avctx) {
fprintf(stderr, "Could not allocate an encoding context\n");
error = AVERROR(ENOMEM);
goto cleanup;
}
/**
* Set the basic encoder parameters.
* The input file's sample rate is used to avoid a sample rate conversion.
*/
avctx->channels = OUTPUT_CHANNELS;
avctx->channel_layout = av_get_default_channel_layout(OUTPUT_CHANNELS);
avctx->sample_rate = input_codec_context->sample_rate;
avctx->sample_fmt = output_codec->sample_fmts[0];
avctx->bit_rate = OUTPUT_BIT_RATE;
/** Allow the use of the experimental AAC encoder */
avctx->strict_std_compliance = FF_COMPLIANCE_EXPERIMENTAL;
/** Set the sample rate for the container. */
stream->time_base.den = input_codec_context->sample_rate;
stream->time_base.num = 1;
/**
* Some container formats (like MP4) require global headers to be present
* Mark the encoder so that it behaves accordingly.
*/
if ((*output_format_context)->oformat->flags & AVFMT_GLOBALHEADER)
avctx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
/** Open the encoder for the audio stream to use it later. */
if ((error = avcodec_open2(avctx, output_codec, NULL)) < 0) {
fprintf(stderr, "Could not open output codec (error '%s')\n",
av_err2str(error));
goto cleanup;
}
error = avcodec_parameters_from_context(stream->codecpar, avctx);
if (error < 0) {
fprintf(stderr, "Could not initialize stream parameters\n");
goto cleanup;
}
/** Save the encoder context for easier access later. */
*output_codec_co
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ffmpeg-3.4.8.zip
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ffmpeg-3.4.8.zip (222个子文件)
ffmpeg-all.1 1.13MB
ffprobe-all.1 907KB
ffmpeg-filters.1 621KB
ffmpeg-codecs.1 159KB
ffmpeg-formats.1 126KB
ffmpeg.1 99KB
ffmpeg-devices.1 71KB
ffmpeg-protocols.1 52KB
ffprobe.1 42KB
ffmpeg-utils.1 36KB
ffmpeg-bitstream-filters.1 15KB
ffmpeg-resampler.1 14KB
ffmpeg-scaler.1 8KB
libswresample.3 6KB
libswscale.3 5KB
libavutil.3 5KB
libavcodec.3 5KB
libavformat.3 5KB
libavdevice.3 5KB
libavfilter.3 5KB
libavutil.dll.a 319KB
libavcodec.dll.a 155KB
libavformat.dll.a 115KB
libavfilter.dll.a 48KB
libswscale.dll.a 22KB
libswresample.dll.a 15KB
libavdevice.dll.a 13KB
libpostproc.dll.a 7KB
transcode_aac.c 28KB
transcoding.c 22KB
muxing.c 21KB
demuxing_decoding.c 14KB
filter_audio.c 12KB
filtering_audio.c 10KB
filtering_video.c 10KB
qsvdec.c 8KB
resampling_audio.c 8KB
hw_decode.c 8KB
encode_audio.c 6KB
remuxing.c 6KB
extract_mvs.c 6KB
avio_dir_cmd.c 6KB
encode_video.c 5KB
decode_audio.c 5KB
decode_video.c 5KB
http_multiclient.c 5KB
scaling_video.c 5KB
avio_reading.c 4KB
metadata.c 2KB
avutil-55.def 12KB
avcodec-57.def 6KB
avformat-57.def 4KB
avfilter-6.def 2KB
swscale-4.def 756B
avdevice-57.def 554B
swresample-2.def 478B
postproc-54.def 233B
avcodec-57.dll 13.16MB
avfilter-6.dll 2.23MB
avformat-57.dll 2.14MB
avutil-55.dll 500KB
swscale-4.dll 465KB
avdevice-57.dll 133KB
postproc-54.dll 128KB
swresample-2.dll 87KB
ffmpeg.exe 284KB
ffprobe.exe 173KB
libvpx-720p.ffpreset 227B
libvpx-1080p.ffpreset 227B
libvpx-1080p50_60.ffpreset 227B
libvpx-720p50_60.ffpreset 227B
libvpx-360p.ffpreset 219B
avcodec.h 213KB
avformat.h 113KB
avfilter.h 42KB
opt.h 35KB
pixfmt.h 34KB
avio.h 31KB
frame.h 26KB
mem.h 23KB
hwcontext.h 22KB
swresample.h 21KB
intreadwrite.h 18KB
avdevice.h 17KB
common.h 15KB
pixdesc.h 15KB
avstring.h 14KB
swscale.h 12KB
log.h 11KB
imgutils.h 11KB
buffer.h 10KB
samplefmt.h 10KB
channel_layout.h 9KB
avutil.h 9KB
hash.h 8KB
dict.h 8KB
version.h 8KB
spherical.h 8KB
mathematics.h 8KB
vdpau.h 8KB
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