修改output-example，将H.264,AAC帧保存到mp4容器中

URL:http://blog.csdn.net/ajaxhe/article/details/7603333

2012/11/26更新 根据网友反馈，原来的下载链接编译有问题，原因是头文件和库文件的路径没有设置好，已经修改。 下载链接： http://download.csdn.net/detail/ajaxhe/4810984

2012/10/25更新 在add_video_stream()中添加 c->cqp = 32;//很关键的参数，不设置的话会导致马赛克，而且它的大小决定着编码的速度和编码后帧的大小

ffmpeg版本：0.8
开发环境：VS2008

遇到的错误：
1. Specified sample_fmt is not supported.

[aac @ 000E6E60] Specified sample_fmt is not supported. could not open audio codec

设置***CodecContext *c的sample_fmt位，如：

c ->sample_fmt = ***_SAMPLE_FMT_S16 ;
2. Too many bits per frame requested

[aac @ 004D6E60] Too many bits per frame requested could not open audio codec

设置***CodecContext *c的bit_rate位，bit_rate = sample_rate
* channels * 2，其中的“2”指的是sample_fmt为16位的缘故，相应的设置如下：
c ->sample_rate = 8000;
c-> channels = 1;
c-> bit_rate = 16000;
遇到的warning:
1. [mp4 @ 006C3580] Codec for stream 1 does not use global headers but container format requires global
headers
因为保存的文件时mp4格式，需要设置c->flags的CODEC_FLAG_GLOBAL_HEADER，如下：

// some formats want stream headers to be separate
if(! strcmp( oc-> oformat-> name, "mp4" )
|| !strcmp (oc ->oformat ->name , "mov" )
|| !strcmp (oc ->oformat ->name , "3gp" ))
c-> flags |= CODEC_FLAG_GLOBAL_HEADER ;
其他情况下可能遇到的错误:
使用这个程序，主要是为了做一个测试，之前是为了将一个RTP音视频H.264+AAC流保存为mp4文件，在保存AAC文件时，执行
if ( av_write_frame( oc, & pkt)
!= 0) {
fprintf( stderr, "Error
while writing audio frame\n" );
exit(1);
}
总是出错，原因就是因为RTP过来的AAC帧包括的七个字节的AAC Header，而这里写av_write_frame()中pkt.data必须为AAC裸数据（不包括AAC Header）,这个需要特别注意.
工程文件：http://download.csdn.net/detail/ajaxhe/4330294
根据网友反馈，原来的下载链接编译有问题，是头文件和库文件的路径问题，已经修改。

下载链接：http://download.csdn.net/detail/ajaxhe/4810984

源文件：
[cpp] view
plaincopy

/*

* 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 <string.h>

#include <math.h>

//#include <time.h>

#include <Windows.h>



#ifndef M_PI

#define M_PI 3.14159265358979323846

#endif



extern "C" {

#include <libavformat/avformat.h>

#include <libswscale/swscale.h>

};



#undef exit



/* 5 seconds stream duration */

#define STREAM_DURATION 5.0

#define STREAM_FRAME_RATE 25 /* 25 images/s */

#define STREAM_NB_FRAMES ((int )(STREAM_DURATION * STREAM_FRAME_RATE ))

#define STREAM_PIX_FMT PIX_FMT_YUV420P /* default pix_fmt */



static int sws_flags = SWS_BICUBIC ;



/**************************************************************/

/* audio output */



float t , tincr , tincr2 ;

int16_t *samples ;

uint8_t *audio_outbuf ;

int audio_outbuf_size ;

int audio_input_frame_size ;



/*

* add an audio output stream

*/

static ***Stream *add_audio_stream (***FormatContext *oc , int codec_id )

{

***CodecContext * c;

***Stream * st;



st = av_new_stream (oc , 1);

if (! st) {

fprintf( stderr, "Could not alloc stream\n" );

exit(1);

}



c = st-> codec;

c-> codec_id = ( CodecID) codec_id;

c-> codec_type = ***MEDIA_TYPE_AUDIO ;



/* put sample parameters */

c-> sample_fmt = ***_SAMPLE_FMT_S16 ;

c-> sample_rate = 8000;

c-> channels = 1;

c-> bit_rate = 16000;



// some formats want stream headers to be separate

if(! strcmp( oc-> oformat-> name, "mp4" ) || !strcmp (oc ->oformat ->name , "mov" ) || !strcmp (oc ->oformat ->name , "3gp" ))

c-> flags |= CODEC_FLAG_GLOBAL_HEADER ;



return st;

}



static void open_audio (***FormatContext *oc , ***Stream *st )

{

***CodecContext * c;

***Codec * codec;



c = st-> codec;



/* find the audio encoder */

codec = avcodec_find_encoder (c ->codec_id );

if (! codec) {

fprintf( stderr, "codec not found\n" );

exit(1);

}



/* open it */

if ( avcodec_open( c, codec) < 0) {

fprintf( stderr, "could not open audio codec\n" );

exit(1);

}



/* init signal generator */

t = 0;

tincr = 2 * M_PI * 110.0 / c-> sample_rate ;

/* increment frequency by 110 Hz per second */

tincr2 = 2 * M_PI * 110.0 / c-> sample_rate / c ->sample_rate ;



audio_outbuf_size = 10000;

audio_outbuf = ( uint8_t *) av_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 = ( int16_t *) av_malloc( audio_input_frame_size * 2 * c ->channels );

}



/* prepare a 16 bit dummy audio frame of 'frame_size' samples and

'nb_channels' channels */

static void get_audio_frame (int16_t *samples , int frame_size , int nb_channels )

{

int j, i, v;

int16_t * q;



q = samples;

for( j=0; j< frame_size; j++) {

v = ( int)( sin( t) * 10000);

for( i = 0; i < nb_channels ; i ++)

* q++ = v;

t += tincr;

tincr += tincr2;

}

}



static void write_audio_frame (***FormatContext *oc , ***Stream *st )

{

***CodecContext * c;

***Packet pkt;

av_init_packet(& pkt);



c = st-> codec;



get_audio_frame( samples, audio_input_frame_size , c ->channels );



pkt. size = avcodec_encode_audio (c , audio_outbuf , audio_outbuf_size , samples );

printf( "[audio] AAC frame len=%d\n" , pkt .size );



//pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);



//pkt.flags |= ***_PKT_FLAG_KEY;

pkt. stream_index= st-> index;

pkt. data= audio_outbuf ;



/* write the compressed frame in the media file */

if ( av_write_frame( oc, & pkt) != 0) {

fprintf( stderr, "Error while writing audio frame\n" );

exit(1);

}

}



static void close_audio (***FormatContext *oc , ***Stream *st )

{

avcodec_close( st-> codec);



av_free( samples);

av_free( audio_outbuf );

}



/**************************************************************/

/* video output */



***Frame *picture , *tmp_picture ;

uint8_t *video_outbuf ;

int frame_count , video_outbuf_size ;



/* add a video output stream */

static ***Stream *add_video_stream (***FormatContext *oc , int codec_id )

{

***CodecContext * c;

***Stream * st;



st = av_new_stream (oc , 0);

if (! st) {

fprintf( stderr, "Could not alloc stream\n" );

exit(1);

}



c = st-> codec;

c-> codec_id = ( CodecID) codec_id;

c-> codec_type = ***MEDIA_TYPE_VIDEO ;



c-> me_range = 16;

c-> max_qdiff = 4;

c-> qmin = 10;

c-> qmax = 51;

c-> qcompress = 0.6;



/* put sample parameters */

c-> bit_rate = 400000;

/* resolution must be a multiple of two */

c-> width = 352;

c-> height = 288;

/* time base: this is the fundamental unit of time (in seconds) in terms

of which frame timestamps are represented. for fixed-fps content,

timebase should be 1/framerate and timestamp increments should be

identically 1. */

c-> time_base. den = STREAM_FRAME_RATE ;

c-> time_base. num = 1;

c-> gop_size = 12; /* emit one intra frame every twelve frames at most */

c-> pix_fmt = STREAM_PIX_FMT ;

if ( c-> codec_id == CODEC_ID_MPEG2VIDEO ) {

/* just for testing, we also add B frames */

c-> max_b_frames = 2;

}

if ( c-> codec_id == CODEC_ID_MPEG1VIDEO ){

/* Needed to avoid using macroblocks in which some coeffs overflow.

This does not happen with normal video, it just happens here as

the motion of the chroma plane does not match the luma plane. */

c-> mb_decision =2;

}



// some formats want stream headers to be separate

if(! strcmp( oc-> oformat-> name, "mp4" ) || !strcmp (oc ->oformat ->name , "mov" ) || !strcmp (oc ->oformat ->name , "3gp" ))

c-> flags |= CODEC_FLAG_GLOBAL_HEADER ;



return st;

}



static ***Frame *alloc_picture (int pix_fmt , int width , int height )

{

***Frame * picture;

uint8_t * picture_buf ;

int size;



picture = avcodec_alloc_frame ();

if (! picture)

return NULL;

size = avpicture_get_size ((PixelFormat )pix_fmt , width , height );

picture_buf = ( uint8_t *) av_malloc( size);

if (! picture_buf ) {

av_free( picture);

return NULL;

}

avpicture_fill(( ***Picture *) picture, picture_buf ,

( PixelFormat )pix_fmt , width , height );

return picture;

}



static void open_video (***FormatContext *oc , ***Stream *st )

{

***Codec * codec;

***CodecContext * c;



c = st-> codec;



/* find the video encoder */

codec = avcodec_find_encoder (c ->codec_id );

if (! codec) {

fprintf( stderr, "codec not found\n" );

exit(1);

}



/* open the codec */

if ( avcodec_open( c, codec) < 0) {

fprintf( stderr, "could not open video codec\n" );

exit(1);

}



video_outbuf = NULL;

if (!( oc-> oformat-> flags & ***FMT_RAWPICTURE )) {

/* allocate output buffer */

/* XXX: API change will be done */

/* buffers passed into lav* can be allocated any way you prefer,

as long as they're aligned enough for the architecture, and

they're freed appropriately (such as using av_free for buffers

allocated with av_malloc) */

video_outbuf_size = 200000;

video_outbuf = (uint8_t *)av_malloc (video_outbuf_size );

}



/* allocate the encoded raw picture */

picture = alloc_picture (c ->pix_fmt , c ->width , c ->height );

if (! picture) {

fprintf( stderr, "Could not allocate picture\n" );

exit(1);

}



/* if the output format is not YUV420P, then a temporary YUV420P

picture is needed too. It is then converted to the required

output format */

tmp_picture = NULL;

if ( c-> pix_fmt != PIX_FMT_YUV420P ) {

tmp_picture = alloc_picture (PIX_FMT_YUV420P , c ->width , c ->height );

if (! tmp_picture ) {

fprintf( stderr, "Could not allocate temporary picture\n" );

exit(1);

}

}

}



/* prepare a dummy image */

static void fill_yuv_image (***Frame *pict , int frame_index , int width , int height )

{

int x, y, i;



i = frame_index;



/* Y */

for( y=0; y< height; y++) {

for( x=0; x< width; x++) {

pict-> data[0][ y * pict-> linesize[0] + x] = x + y + i * 3;

}

}



/* Cb and Cr */

for( y=0; y< height/2; y++) {

for( x=0; x< width/2; x++) {

pict-> data[1][ y * pict-> linesize[1] + x] = 128 + y + i * 2;

pict-> data[2][ y * pict-> linesize[2] + x] = 64 + x + i * 5;

}

}

}



static void write_video_frame (***FormatContext *oc , ***Stream *st )

{

int out_size, ret;

***CodecContext * c;

static struct SwsContext * img_convert_ctx ;



c = st-> codec;



if ( frame_count >= STREAM_NB_FRAMES ) {

/* no more frame to compress. The codec has a latency of a few

frames if using B frames, so we get the last frames by

passing the same picture again */

} else {

if ( c-> pix_fmt != PIX_FMT_YUV420P ) {

/* as we only generate a YUV420P picture, we must convert it

to the codec pixel format if needed */

if ( img_convert_ctx == NULL ) {

img_convert_ctx = sws_getContext (c ->width , c ->height , PIX_FMT_YUV420P ,

c-> width, c-> height, c ->pix_fmt ,

sws_flags, NULL, NULL, NULL );

if ( img_convert_ctx == NULL ) {

fprintf( stderr, "Cannot initialize the conversion context\n");

exit(1);

}

}

fill_yuv_image (tmp_picture , frame_count , c ->width , c ->height );

sws_scale( img_convert_ctx , tmp_picture ->data , tmp_picture ->linesize ,

0, c-> height, picture-> data, picture-> linesize);

} else {

fill_yuv_image (picture , frame_count , c ->width , c ->height );

}

}





if ( oc-> oformat-> flags & ***FMT_RAWPICTURE ) {

/* raw video case. The API will change slightly in the near

futur for that */

***Packet pkt;

av_init_packet (&pkt );



pkt. flags |= ***_PKT_FLAG_KEY ;

pkt. stream_index = st ->index ;

pkt. data= ( uint8_t *) picture;

pkt. size= sizeof( ***Picture);



ret = av_write_frame (oc , &pkt );

}

else {

/* encode the image */

//printf("frame count %d\n", frame_count);

out_size = avcodec_encode_video (c , video_outbuf , video_outbuf_size , picture );

/* if zero size, it means the image was buffered */

if ( out_size > 0) {

***Packet pkt;

av_init_packet (&pkt );



/*

// 很关键

if (c->codec_id == CODEC_ID_H264)

pkt.pts = av_rescale_q(frame_count, c->time_base, st->time_base);

else

pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);

*/



if( c-> coded_frame ->key_frame ){

pkt. flags |= ***_PKT_FLAG_KEY ;

}



pkt. stream_index = st ->index ;

pkt. data= video_outbuf ;

// not the video_outbuf_size, note!

pkt. size= out_size;



/* write the compressed frame in the media file */

ret = av_write_frame (oc , &pkt );



frame_count ++;

}

else {

ret = 0;

}

}

if ( ret != 0) {

fprintf( stderr, "Error while writing video frame\n" );

exit(1);

}

}



static void close_video (***FormatContext *oc , ***Stream *st )

{

avcodec_close( st-> codec);

av_free( picture-> data[0]);

av_free( picture);

if ( tmp_picture) {

av_free( tmp_picture ->data [0]);

av_free( tmp_picture );

}

av_free( video_outbuf );

}



/**************************************************************/

/* media file output */



int main (int argc , char **argv )

{

const char filename[] = "output.mp4" ;

***OutputFormat * fmt;

***FormatContext * oc;

***Stream * audio_st;

double audio_pts;

***Stream * video_st;

double video_pts;

int i;



/* initialize libavcodec, and register all codecs and formats */

av_register_all();



/*

if (argc != 2) {

printf("usage: %s output_file\n"

"API example program to output a media file with libavformat.\n"

"The output format is automatically guessed according to the file extension.\n"

"Raw images can also be output by using '%%d' in the filename\n"

"\n", argv[0]);

exit(1);

}



filename = argv[1];

*/



/* auto detect the output format from the name. default is mpeg. */

fmt = av_guess_format (NULL , filename , NULL );

//fmt = av_guess_format("h264", NULL, NULL);



if (! fmt) {

printf( "Could not deduce output format from file extension: using MPEG.\n");

fmt = av_guess_format ("mpeg" , NULL , NULL );

}

if (! fmt) {

fprintf( stderr, "Could not find suitable output format\n" );

exit(1);

}



/* allocate the output media context */

oc = avformat_alloc_context ();



if (! oc) {

fprintf( stderr, "Memory error\n" );

exit(1);

}

oc-> oformat = fmt;



fmt-> video_codec = (CodecID ) CODEC_ID_H264 ;

fmt-> audio_codec = (CodecID ) CODEC_ID_AAC ;



_snprintf( oc-> filename, sizeof( oc-> filename), "%s" , filename );



/* add the audio and video streams using the default format codecs

and initialize the codecs */

video_st = NULL;

if ( fmt-> video_codec != CODEC_ID_NONE ) {

video_st = add_video_stream (oc , fmt ->video_codec );

}



audio_st = NULL;

if ( fmt-> audio_codec != CODEC_ID_NONE ) {

audio_st = add_audio_stream (oc , fmt ->audio_codec );

}



/* set the output parameters (must be done even if no parameters). */

if ( av_set_parameters( oc, NULL) < 0) {

fprintf( stderr, "Invalid output format parameters\n" );

exit(1);

}



dump_format( oc, 0, filename, 1);



/* now that all the parameters are set, we can open the audio and

video codecs and allocate the necessary encode buffers */

if ( video_st)

open_video( oc, video_st);

if ( audio_st)

open_audio( oc, audio_st);



/* open the output file */

if (!( fmt-> flags & ***FMT_NOFILE )) {

if ( url_fopen(& oc-> pb, filename, URL_WRONLY) < 0) {

fprintf( stderr, "Could not open '%s'\n" , filename );

exit(1);

}

}



/* write the stream header, if any */

if( av_write_header (oc ) < 0)

{

fprintf( stderr, "Could not write header for output file\n" );

return -1;

}



//long startTime = GetTickCount();



for(;;) {

// compute current audio and video time

if ( audio_st)

audio_pts = ( double) audio_st-> pts. val * audio_st ->time_base .num / audio_st ->time_base .den ;

else

audio_pts = 0.0;



if ( video_st)

video_pts = ( double) video_st-> pts. val * video_st ->time_base .num / video_st ->time_base .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_st && audio_pts < video_pts )) {

write_audio_frame (oc , audio_st );

} else {

write_video_frame (oc , video_st );

}

}



//printf("encode 250 frames, total time:%ld\n", GetTickCount()-startTime);



/* close each codec */

if ( video_st)

close_video (oc , video_st );



if ( audio_st)

close_audio (oc , audio_st );



/* write the trailer, if any */

int res = av_write_trailer (oc );



/* free the streams */

for( i = 0; i < oc-> nb_streams; i++) {

av_freep(& oc-> streams[ i]-> codec);

av_freep(& oc-> streams[ i]);

}



if (!( fmt-> flags & ***FMT_NOFILE )) {

/* close the output file */

url_fclose( oc-> pb);

}



/* free the stream */

av_free( oc);



return 0;

}