直接编译tutorial03.c是会报错的

 

 

 

root@ubuntu:/home/zhangbin/code# gcc -o tutorial03 tutorial03.c -lavformat -lavcodec -lz -lm `sdl-config --cflags --libs` 

 

tutorial03.c:1:28: error: ffmpeg/avcodec.h: No such file or directory

tutorial03.c:2:29: error: ffmpeg/avformat.h: No such file or directory

tutorial03.c:16: error: expected specifier-qualifier-list before ‘AVPacketList’

tutorial03.c: In function ‘packet_queue_init’:

tutorial03.c:29: error: ‘PacketQueue’ has no member named ‘mutex’

tutorial03.c:30: error: ‘PacketQueue’ has no member named ‘cond’

tutorial03.c: At top level:

tutorial03.c:32: error: expected declaration specifiers or ‘...’ before ‘AVPacket’

tutorial03.c: In function ‘packet_queue_put’:

tutorial03.c:34: error: ‘AVPacketList’ undeclared (first use in this function)

tutorial03.c:34: error: (Each undeclared identifier is reported only once

tutorial03.c:34: error: for each function it appears in.)

tutorial03.c:34: error: ‘pkt1’ undeclared (first use in this function)

tutorial03.c:35: error: ‘pkt’ undeclared (first use in this function)

tutorial03.c:45: error: ‘PacketQueue’ has no member named ‘mutex’

tutorial03.c:47: error: ‘PacketQueue’ has no member named ‘last_pkt’

tutorial03.c:48: error: ‘PacketQueue’ has no member named ‘first_pkt’

tutorial03.c:50: error: ‘PacketQueue’ has no member named ‘last_pkt’

tutorial03.c:51: error: ‘PacketQueue’ has no member named ‘last_pkt’

tutorial03.c:52: error: ‘PacketQueue’ has no member named ‘nb_packets’

tutorial03.c:53: error: ‘PacketQueue’ has no member named ‘size’

tutorial03.c:54: error: ‘PacketQueue’ has no member named ‘cond’

tutorial03.c:56: error: ‘PacketQueue’ has no member named ‘mutex’

tutorial03.c: At top level:

tutorial03.c:59: error: expected declaration specifiers or ‘...’ before ‘AVPacket’

tutorial03.c: In function ‘packet_queue_get’:

tutorial03.c:61: error: ‘AVPacketList’ undeclared (first use in this function)

tutorial03.c:61: error: ‘pkt1’ undeclared (first use in this function)

tutorial03.c:64: error: ‘PacketQueue’ has no member named ‘mutex’

tutorial03.c:73: error: ‘PacketQueue’ has no member named ‘first_pkt’

tutorial03.c:75: error: ‘PacketQueue’ has no member named ‘first_pkt’

tutorial03.c:76: error: ‘PacketQueue’ has no member named ‘first_pkt’

tutorial03.c:77: error: ‘PacketQueue’ has no member named ‘last_pkt’

tutorial03.c:78: error: ‘PacketQueue’ has no member named ‘nb_packets’

tutorial03.c:79: error: ‘PacketQueue’ has no member named ‘size’

tutorial03.c:80: error: ‘pkt’ undeclared (first use in this function)

tutorial03.c:88: error: ‘PacketQueue’ has no member named ‘cond’

tutorial03.c:88: error: ‘PacketQueue’ has no member named ‘mutex’

tutorial03.c:91: error: ‘PacketQueue’ has no member named ‘mutex’

tutorial03.c: At top level:

tutorial03.c:95: error: expected ‘)’ before ‘*’ token

tutorial03.c: In function ‘audio_callback’:

tutorial03.c:139: error: ‘AVCodecContext’ undeclared (first use in this function)

tutorial03.c:139: error: ‘aCodecCtx’ undeclared (first use in this function)

tutorial03.c:139: error: expected expression before ‘)’ token

tutorial03.c:142: error: ‘AVCODEC_MAX_AUDIO_FRAME_SIZE’ undeclared (first use in this function)

tutorial03.c: In function ‘main’:

tutorial03.c:170: error: ‘AVFormatContext’ undeclared (first use in this function)

tutorial03.c:170: error: ‘pFormatCtx’ undeclared (first use in this function)

tutorial03.c:172: error: ‘AVCodecContext’ undeclared (first use in this function)

tutorial03.c:172: error: ‘pCodecCtx’ undeclared (first use in this function)

tutorial03.c:173: error: ‘AVCodec’ undeclared (first use in this function)

tutorial03.c:173: error: ‘pCodec’ undeclared (first use in this function)

tutorial03.c:174: error: ‘AVFrame’ undeclared (first use in this function)

tutorial03.c:174: error: ‘pFrame’ undeclared (first use in this function)

tutorial03.c:175: error: ‘AVPacket’ undeclared (first use in this function)

tutorial03.c:175: error: expected ‘;’ before ‘packet’

tutorial03.c:179: error: ‘aCodecCtx’ undeclared (first use in this function)

tutorial03.c:180: error: ‘aCodec’ undeclared (first use in this function)

tutorial03.c:215: error: ‘CODEC_TYPE_VIDEO’ undeclared (first use in this function)

tutorial03.c:219: error: ‘CODEC_TYPE_AUDIO’ undeclared (first use in this function)

tutorial03.c:291: error: ‘packet’ undeclared (first use in this function)

tutorial03.c:302: error: ‘AVPicture’ undeclared (first use in this function)

tutorial03.c:302: error: expected ‘;’ before ‘pict’

tutorial03.c:303: error: ‘pict’ undeclared (first use in this function)

tutorial03.c:312: error: ‘PIX_FMT_YUV420P’ undeclared (first use in this function)

tutorial03.c:313: error: expected expression before ‘)’ token

tutorial03.c:326: error: too many arguments to function ‘packet_queue_put’

root@ubuntu:/home/zhangbin/code# 

 

 

改了一下头文件

 

#include "libavcodec/avcodec.h"

#include "libavformat/avformat.h"

 

会去/usr/local/include/libavcodec/avcodec.h寻找。

 

 

 

 

root@ubuntu:/home/zhangbin/code# vi tutorial03.c

root@ubuntu:/home/zhangbin/code# gcc -o tutorial03 tutorial03.c -lavformat -lavcodec -lz -lm `sdl-config --cflags --libs` 

tutorial03.c: In function ‘audio_decode_frame’:

tutorial03.c:106: warning: ‘avcodec_decode_audio2’ is deprecated (declared at /usr/local/include/libavcodec/avcodec.h:3593)

tutorial03.c: In function ‘main’:

tutorial03.c:295: warning: ‘avcodec_decode_video’ is deprecated (declared at /usr/local/include/libavcodec/avcodec.h:3655)

/tmp/cc6TCXLI.o: In function `main':

tutorial03.c:(.text+0xa23): undefined reference to `img_convert'

collect2: ld returned 1 exit status

===============================================================================

参考 http://blog.sina.com.cn/s/blog_5c4dd3330100mr01.html

牛人的：

undefined reference to 'img_convert'，sws_scale替换了img_convert

早期的ffmpeg库中，采用img_convert图像格式转换，而较新的ffmpeg库中去掉了该函数，加入了swscale库，用该库中的sws_scale函数可以替代img_convert，两个函数原型如下：

int img_convert(AVPicture *dst, int dst_pix_fmt, const AVPicture *src, int src_pix_fmt, int src_width, int src_height) int sws_scale(struct SwsContext *ctx, uint8_t* src[], int srcStride[], int srcSliceY, int srcSliceH, uint8_t* dst[], int dstStride[]) 

为了方便，可以自己写一个img_convert函数，然后函数内部用sws_scale来实现，只是对于一些错误的处理及返回值处理不太严格，但基本能用，代码如下：

int img_convert(AVPicture *dst, int dst_pix_fmt, const AVPicture *src, int src_pix_fmt, int src_width, int src_height) { int w; int h; SwsContext *pSwsCtx; w = src_width; h = src_height; pSwsCtx = sws_getContext(w, h, src_pix_fmt, w, h, dst_pix_fmt, SWS_BICUBIC, NULL, NULL, NULL); sws_scale(pSwsCtx, src->data, src->linesize, 0, h, dst->data, dst->linesize); return 0; }  

同时，有位网友说：

sws_scale结束后，pSwsCtx要注意释放内存，否则，会导致程序会不断地吞吃内存的。

================================================================================

还有另一位牛人的：

大家好，我的问题已经解决，
问题出现在我下载的ffmpeg的版本不一样，我是用svn下载了最新的版本，在这个版本的函数库里没有img_convert函数，在0.4.8以前的版本中还有这个函数，新版本中用sws_getContext和sws_scale代替了。简单说明如下：

新版本的ffmpeg添加了新的接口：libswscale来处理图像缩放。

以前使用img_convert来把RGB转换成YUV12，现在使用新的接口。新接口更加标准和快速，而且里面有了MMX优化代码。换句话说，它是做缩放更好的方式。

用来缩放的基本函数是sws_scale。但一开始，必需建立一个 SwsContext的概念。这将进行想要的转换，然后把它传递给 sws_scale函数。 类似于在SQL中的预备阶段或者是在Python中编译的规则表达式regexp。要准备这个上下文，使用 sws_getContext函数，它需要源的宽度和高度，我们想要的宽度和高度，源的格式和想要转换成的格式，同时还有一些其它的参数和标志。然后我们像使用img_convert一样来使用sws_scale函数，唯一不同的是我们传递给的是SwsContext。

具体说明看tutorial08.txt （在什么地方？）

还有想对woshizp说：我会发一封邮件给你，把我最近学习ffmpeg的心得给你。

最后谢谢morris88

================================================================================

最后参考

http://witmax.cn/ffmpeg-img-convert.html

解决办法是将原有的img_convert函数改为sws_scale函数，原来的函数调用为：

// Convert the image from its native format to RGB img_convert((AVPicture *)pFrameRGB, PIX_FMT_RGB24, (AVPicture*)pFrame, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height); 

现在改成了：

#include <ffmpeg/swscale.h> // other codes static struct SwsContext *img_convert_ctx; // other codes img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, PIX_FMT_RGB24, SWS_BICUBIC, NULL, NULL, NULL); // other codes // Convert the image from its native format to RGB sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameRGB->data, pFrameRGB->linesize) 

修改之后，我遇到了这样的情况：

root@ubuntu:/home/zhangbin/code# gcc -o tutorial03 tutorial03.c -lavformat -lavcodec -lz -lm `sdl-config --cflags --libs` 

tutorial03.c: In function ‘audio_decode_frame’:

tutorial03.c:107: warning: ‘avcodec_decode_audio2’ is deprecated (declared at /usr/local/include/libavcodec/avcodec.h:3593)

tutorial03.c: In function ‘main’:

tutorial03.c:296: warning: ‘avcodec_decode_video’ is deprecated (declared at /usr/local/include/libavcodec/avcodec.h:3655)

tutorial03.c:321: warning: ‘sws_getContext’ is deprecated (declared at /usr/local/include/libswscale/swscale.h:191)

tutorial03.c:326: error: ‘ pFrameRGB’ undeclared (first use in this function)

tutorial03.c:326: error: (Each undeclared identifier is reported only once

tutorial03.c:326: error: for each function it appears in.)

 

================================================

 

root@ubuntu:/etc/vim# vi vimrc

set number之后，找到326行。

==============================================

发现原文是tutorial01.c

修改tutorial01.c发现：

 

root@ubuntu:/home/zhangbin/code# vi tutorial01.c

root@ubuntu:/home/zhangbin/code# gcc -o tutorial01 tutorial01.c -lavformat -lavcodec -lz

tutorial01.c: In function ‘main’:

tutorial01.c:128: warning: ‘avcodec_decode_video’ is deprecated (declared at /usr/local/include/libavcodec/avcodec.h:3655)

tutorial01.c:141: warning: ‘sws_getContext’ is deprecated (declared at /usr/local/include/libswscale/swscale.h:191)

/tmp/ccALn29e.o: In function `main':

tutorial01.c:(.text+0x425): undefined reference to `sws_getContext'

tutorial01.c:(.text+0x47f): undefined reference to `sws_scale'

collect2: ld returned 1 exit status

=======================================================================================================

 

======================================================================

然后测试一下：

root@ubuntu:/home/zhangbin# tutorial01 oldboy.mp4

tutorial01: command not found

root@ubuntu:/home/zhangbin# ./tutorial01 oldboy.mp4

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'oldboy.mp4':

  Metadata:

    major_brand     : isom

    minor_version   : 1

    compatible_brands: isom

    creation_time   : 2010-10-31 03:36:12

  Duration: 00:42:37.76, start: 0.000000, bitrate: 506 kb/s

    Stream #0.0(und): Video: h264, yuv420p, 672x378 [PAR 1:1 DAR 16:9], 471 kb/s, 25 fps, 25 tbr, 25k tbn, 50 tbc

    Metadata:

      creation_time   : 2010-10-26 15:52:54

    Stream #0.1(und): Audio: aac, 44100 Hz, stereo, s16, 31 kb/s

    Metadata:

      creation_time   : 2010-10-31 03:36:14

然后，好像是虚拟机里头的ubuntu死机了。

然后出现了窗口主题都被变了情况，多了五个ppm文件。

然后我重启了虚拟机。

 

 

==========================

这次我选了一个305kB的mpg文件，因为作者给的参考就是mpg格式的。