/*
* Copyright (c) 2013-2018 Andreas Unterweger
*
* 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.
* Formats other than MP4 are supported based on the output file extension.
* @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 bit/s */
#define OUTPUT_BIT_RATE 96000
/* The number of output channels */
#define OUTPUT_CHANNELS 2
/**
* Open an input file and the required decoder.
* @param filename File to be opened
* @param[out] input_format_context Format context of opened file
* @param[out] input_codec_context Codec context of opened file
* @return Error code (0 if successful)
*/
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.
* @param filename File to be opened
* @param input_codec_context Codec context of input file
* @param[out] output_format_context Format context of output file
* @param[out] output_codec_context Codec context of output file
* @return Error code (0 if successful)
*/
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;
}
if (!((*output_format_context)->url = av_strdup(filename))) {
fprintf(stderr, "Could not allocate url.\n");
error = AVERROR(ENOMEM);
goto cleanup;
}
/* 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.
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window平台FFmpeg开发实例
共1095个文件
h:738个
c:69个
dll:64个
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window平台FFmpeg开发实例 (1095个子文件)
ffprobe-all.1 1.13MB
ffmpeg-filters.1 824KB
ffmpeg-codecs.1 181KB
ffmpeg-formats.1 164KB
ffmpeg-devices.1 73KB
ffmpeg-protocols.1 70KB
ffprobe.1 41KB
ffmpeg-utils.1 36KB
ffmpeg-bitstream-filters.1 31KB
ffmpeg-resampler.1 14KB
ffmpeg-scaler.1 9KB
libswresample.3 6KB
libswscale.3 5KB
libavutil.3 5KB
libavcodec.3 5KB
libavformat.3 5KB
libavdevice.3 5KB
libavfilter.3 5KB
libavutil.dll.a 347KB
libavutil.dll.a 347KB
libavutil.dll.a 338KB
libavutil.dll.a 338KB
libavutil.dll.a 338KB
libavcodec.dll.a 153KB
libavcodec.dll.a 153KB
libavcodec.dll.a 152KB
libavcodec.dll.a 150KB
libavcodec.dll.a 150KB
libavformat.dll.a 114KB
libavformat.dll.a 114KB
libavformat.dll.a 111KB
libavformat.dll.a 111KB
libavformat.dll.a 111KB
libavfilter.dll.a 46KB
libavfilter.dll.a 46KB
libavfilter.dll.a 45KB
libavfilter.dll.a 45KB
libavfilter.dll.a 45KB
libswscale.dll.a 22KB
libswscale.dll.a 22KB
libswscale.dll.a 22KB
libswscale.dll.a 22KB
libswscale.dll.a 22KB
libswresample.dll.a 15KB
libswresample.dll.a 15KB
libswresample.dll.a 15KB
libswresample.dll.a 15KB
libswresample.dll.a 15KB
libavdevice.dll.a 13KB
libavdevice.dll.a 13KB
libavdevice.dll.a 13KB
libavdevice.dll.a 13KB
libavdevice.dll.a 13KB
transcode_aac.c 34KB
transcode_aac.c 34KB
transcode_aac.c 34KB
transcoding.c 22KB
transcoding.c 22KB
transcoding.c 22KB
muxing.c 21KB
muxing.c 21KB
muxing.c 21KB
demuxing_decoding.c 13KB
demuxing_decoding.c 13KB
demuxing_decoding.c 13KB
filter_audio.c 12KB
filter_audio.c 12KB
filter_audio.c 12KB
filtering_audio.c 10KB
filtering_audio.c 10KB
filtering_audio.c 10KB
vaapi_transcode.c 10KB
vaapi_transcode.c 10KB
vaapi_transcode.c 10KB
filtering_video.c 9KB
filtering_video.c 9KB
filtering_video.c 9KB
qsvdec.c 8KB
qsvdec.c 8KB
qsvdec.c 8KB
resampling_audio.c 8KB
resampling_audio.c 8KB
resampling_audio.c 8KB
hw_decode.c 8KB
hw_decode.c 8KB
hw_decode.c 8KB
decode_audio.c 7KB
decode_audio.c 7KB
decode_audio.c 7KB
vaapi_encode.c 7KB
vaapi_encode.c 7KB
vaapi_encode.c 7KB
encode_audio.c 6KB
encode_audio.c 6KB
encode_audio.c 6KB
remuxing.c 6KB
remuxing.c 6KB
remuxing.c 6KB
extract_mvs.c 6KB
extract_mvs.c 6KB
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