我正在尝试写一篇短片＆＃39; C＆＃39;使用FFMPEG读取音频文件的程序，使用＆＃39; C＆＃39;程序，然后通过FFMEPG输出文件，FFMEPG使用FFMPEG showwaves过滤器将新的，修改过的音频与视频表示相结合。
目前该计划尝试执行以下操作： -
i）使用pipein thorugh FFMPEG读入音频文件 ii）使用“C＆＃39;”的一部分处理音频文件。程序 iii）将修改后的音频输出到FFMPEG，并使用“showwaves”生成文件。在FFMEPG中过滤以创建带有音频和视频的MP4文件。
以下代码从FFMPEG中的ommand行运行生成我想要创建的音频/视频MP4： -
ffmpeg -y -f s16le -ar 44100 -ac 1 -i 12345678.wav -i 12345678.wav -filter_complex "[0:a]showwaves=s=1280x720:mode=line:rate=25,format=yuv420p[v]" -map "[v]" -map 1:a:0 -codec:v libx264 -crf 21 -bf 2 -flags +cgop -pix_fmt yuv420p -codec:a aac -strict -2 -b:a 384k -r:a 48000 -movflags faststart 12345678.mp4
＆＃34;
此代码生成已处理的音频文件，并根据需要将其输出到.wav文件： -
#include <stdio.h>
#include <stdint.h>
#include <math.h>
void main()
{
// Launch two instances of FFmpeg, one to read the original WAV
// file and another to write the modified WAV file. In each case,
// data passes between this program and FFmpeg through a pipe.
FILE *pipein;
FILE *pipeout;
pipein = popen("ffmpeg -i 12345678.wav -f s16le -ac 1 -", "r");
pipeout = popen("ffmpeg -y -f s16le -ar 44100 -ac 1 -i - out.wav", "w");
// Read, modify and write one sample at a time
int16_t sample;
int count, n=0;
while(1)
{
count = fread(&sample, 2, 1, pipein); // read one 2-byte sample
if (count != 1) break;
++n;
sample = sample * sin(n * 5.0 * 2*M_PI / 44100.0);
fwrite(&sample, 2, 1, pipeout);
}
// Close input and output pipes
pclose(pipein);
pclose(pipeout);
}
（此代码借鉴了特德伯克的优秀帖子here）
我已尝试如下所示，但这不起作用： -
#include <stdio.h>
#include <stdint.h>
#include <math.h>
void main()
{
// Launch two instances of FFmpeg, one to read the original WAV
// file and another to write the modified WAV file. In each case,
// data passes between this program and FFmpeg through a pipe.
FILE *pipein;
FILE *pipeout;
pipein = popen("ffmpeg -i 12345678.wav -f s16le -ac 1 -", "r");
pipeout = popen("ffmpeg -y -f s16le -ar 44100 -ac 1 -i 12345678.wav -i
12345678.wav -filter_complex "
[0:a]showwaves=s=1280x720:mode=line:rate=25,format=yuv420p[v]" -map "[v]"
-map 1:a:0 -codec:v libx264 -crf 21 -bf 2 -flags +cgop -pix_fmt yuv420p -
codec:a aac -strict -2 -b:a 384k -r:a 48000 -movflags faststart
12345678.mp4
", "w");
// Read, modify and write one sample at a time
int16_t sample;
int count, n=0;
while(1)
{
count = fread(&sample, 2, 1, pipein); // read one 2-byte sample
if (count != 1) break;
++n;
sample = sample * sin(n * 5.0 * 2*M_PI / 44100.0);
fwrite(&sample, 2, 1, pipeout);
}
// Close input and output pipes
pclose(pipein);
pclose(pipeout);
}
理想情况下，有人可以建议上面的管道输出命令的改进版本 - 另外另一个实现此目的的过程将是有趣的
*编辑*
感谢@Mulvya，修改后的管道输出线现在是： -
pipeout = popen("ffmpeg -y -f s16le -ar 44100 -ac 1 -i - -filter_complex "[0:a]showwaves=s=1280x720:mode=line:rate=25,format=yuv420p[v]" -map "[v]" -map 1:a:0 -codec:v libx264 -crf 21 -bf 2 -flags +cgop -pix_fmt yuv420p -codec:a aac -strict -2 -b:a 384k -r:a 48000 -movflags faststart 12345678.mp4
＆＃34;，＆＃34; w＆＃34;）;
在使用gcc编译时，我收到以下错误消息： -
avtovid2.c: In function \u2018main\u2019:
wavtovid2.c:13:83: error: expected \u2018]\u2019 before \u2018:\u2019
token
pipeout = popen("ffmpeg -y -f s16le -ar 44100 -ac 1 -i - -
filter_complex "
[0:a]showwaves=s=1280x720:mode=line:rate=25,format=yuv420p[v]" -map "[v]"
-map 1:a:0 -codec:v libx264 -crf 21 -bf 2 -flags +cgop -pix_fmt yuv420p -
codec:a aac -strict -2 -b:a 384k -r:a 48000 -movflags faststart
12345678.mp4
^
wavtovid2.c:13:86: error: expected \u2018)\u2019 before
\u2018showwaves\u2019
pipeout = popen("ffmpeg -y -f s16le -ar 44100 -ac 1 -i - -
filter_complex "
[0:a]showwaves=s=1280x720:mode=line:rate=25,format=yuv420p[v]" -map "[v]"
-map 1:a:0 -codec:v libx264 -crf 21 -bf 2 -flags +cgop -pix_fmt yuv420p -
codec:a aac -strict -2 -b:a 384k -r:a 48000 -movflags faststart
12345678.mp4
^
wavtovid2.c:13:98: error: invalid suffix "x720" on integer constant
pipeout = popen("ffmpeg -y -f s16le -ar 44100 -ac 1 -i - -
filter_complex "
[0:a]showwaves=s=1280x720:mode=line:rate=25,format=yuv420p[v]" -map "[v]"
-map 1:a:0 -codec:v libx264 -crf 21 -bf 2 -flags +cgop -pix_fmt yuv420p -
codec:a aac -strict -2 -b:a 384k -r:a 48000 -movflags faststart
12345678.mp4
^
wavtovid2.c:13:153: warning: missing terminating " character
pipeout = popen("ffmpeg -y -f s16le -ar 44100 -ac 1 -i - -
filter_complex "
[0:a]showwaves=s=1280x720:mode=line:rate=25,format=yuv420p[v]" -map "[v]"
-map 1:a:0 -codec:v libx264 -crf 21 -bf 2 -flags +cgop -pix_fmt yuv420p -
codec:a aac -strict -2 -b:a 384k -r:a 48000 -movflags faststart
12345678.mp4
^
wavtovid2.c:13:86: error: missing terminating " character
pipeout = popen("ffmpeg -y -f s16le -ar 44100 -ac 1 -i - -
filter_complex "
[0:a]showwaves=s=1280x720:mode=line:rate=25,format=yuv420p[v]" -map "[v]"
-map 1:a:0 -codec:v libx264 -crf 21 -bf 2 -flags +cgop -pix_fmt yuv420p -
codec:a aac -strict -2 -b:a 384k -r:a 48000 -movflags faststart
12345678.mp4
^
wavtovid2.c:14:6: warning: missing terminating " character
", "w");
^
wavtovid2.c:14:1: error: missing terminating " character
", "w");
^
wavtovid2.c:13:21: warning: passing argument 1 of \u2018popen\u2019 makes
pointer from integer without a cast
pipeout = popen("ffmpeg -y -f s16le -ar 44100 -ac 1 -i - -
filter_complex "
[0:a]showwaves=s=1280x720:mode=line:rate=25,format=yuv420p[v]" -map "[v]"
-map 1:a:0 -codec:v libx264 -crf 21 -bf 2 -flags +cgop -pix_fmt yuv420p -
codec:a aac -strict -2 -b:a 384k -r:a 48000 -movflags faststart
12345678.mp4
^
In file included from wavtovid2.c:1:0:
/usr/include/stdio.h:872:14: note: expected \u2018const char *\u2019 but
argument is of type \u2018char\u2019
extern FILE *popen (const char *__command, const char *__modes) __wur;
^
wavtovid2.c:13:15: error: too few arguments to function \u2018popen\u2019
pipeout = popen("ffmpeg -y -f s16le -ar 44100 -ac 1 -i - -
filter_complex "
[0:a]showwaves=s=1280x720:mode=line:rate=25,format=yuv420p[v]" -map "[v]"
-map 1:a:0 -codec:v libx264 -crf 21 -bf 2 -flags +cgop -pix_fmt yuv420p -
codec:a aac -strict -2 -b:a 384k -r:a 48000 -movflags faststart
12345678.mp4
^
In file included from wavtovid2.c:1:0:
/usr/include/stdio.h:872:14: note: declared here
extern FILE *popen (const char *__command, const char *__modes) __wur;
^
wavtovid2.c:32:1: error: expected \u2018;\u2019 before \u2018}\u2019
token
}
答案 0 :(得分：0)
这是一个工作版本 - 感谢@Mulvya的帮助，感谢Ted Burke的原始代码。
该程序将通过FFMPEG读入名为12345678.wav的文件，并在＆＃39; C＆＃39;中处理该文件。产生颤音效果，然后将音频输出到名为12345678.mp4的视频文件中，并使用FFMEPG＆lt; showwaves＆＃39;生成视频。过滤器： -
#include <stdio.h>
#include <stdint.h>
#include <math.h>
void main()
{
// Launch two instances of FFmpeg, one to read the original WAV
// file and another to write the modified WAV file. In each case,
// data passes between this program and FFmpeg through a pipe.
FILE *pipein;
FILE *pipeout;
pipein = popen("ffmpeg -i 12345678.wav -f s16le -ac 1 -", "r");
pipeout = popen("ffmpeg -y -f s16le -ar 44100 -ac 1 -i - -filter_complex
[0:a]showwaves=s=1280x720:mode=line:rate=25,format=yuv420p[v] -map [v] -
map 0:a -codec:a aac -strict -2 12345678.mp4", "w");
// Read, modify and write one sample at a time
int16_t sample;
int count, n=0;
while(1)
{
count = fread(&sample, 2, 1, pipein); // read one 2-byte sample
if (count != 1) break;
++n;
sample = sample * sin(n * 5.0 * 2*M_PI / 44100.0);
fwrite(&sample, 2, 1, pipeout);
}
// Close input and output pipes
pclose(pipein);
pclose(pipeout);
}
这仍然需要一些工作来理解FFMPEG管道限制，并改进输出文件规范。
该程序的目的是作为开发程序的第一步，该程序可以接受和处理C＆＃39;中的音频文件，并使用FFMPEG生成组合的音频和视频输出。