104 lines
2.8 KiB
C
104 lines
2.8 KiB
C
/*
|
|
extract_frams: utlize the framebyframe API and mpg123_framedata to extract the MPEG frames out of a stream (strip off anything else).
|
|
|
|
This is example code only sensible to be considered in the public domain.
|
|
Initially written by Thomas Orgis.
|
|
*/
|
|
|
|
#include <mpg123.h>
|
|
|
|
/* unistd.h is not available under MSVC,
|
|
io.h defines the read and write functions */
|
|
#ifndef _MSC_VER
|
|
#include <unistd.h>
|
|
#else
|
|
#include <io.h>
|
|
#endif
|
|
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
|
|
/** The actual work on the existing handle. */
|
|
int do_work(mpg123_handle *m);
|
|
|
|
/** The main program. */
|
|
int main(int argc, char **argv)
|
|
{
|
|
int ret = 0;
|
|
mpg123_handle *m;
|
|
|
|
#if MPG123_API_VERSION < 46
|
|
// Newer versions of the library don't need that anymore, but it is safe
|
|
// to have the no-op call present for compatibility with old versions.
|
|
mpg123_init();
|
|
#endif
|
|
m = mpg123_new(NULL, &ret);
|
|
|
|
if(m == NULL)
|
|
{
|
|
fprintf(stderr, "Cannot create handle: %s", mpg123_plain_strerror(ret));
|
|
}
|
|
else
|
|
{
|
|
fprintf(stderr, "I'll take your dirty MPEG audio from standard input and will write the extracted pure MPEG data to standard output.\n");
|
|
if(argc > 1 && strcmp(argv[1], "--noinfo") == 0)
|
|
{
|
|
fprintf(stderr, "Enabling parsing/consuming of the Info frame so that it will not appear in output.\n");
|
|
ret = mpg123_param(m, MPG123_REMOVE_FLAGS, MPG123_IGNORE_INFOFRAME, 0.);
|
|
}
|
|
else
|
|
{
|
|
fprintf(stderr, "If you'd have given --noinfo as argument, I would omit a LAME/Xing info frame.\n");
|
|
ret = mpg123_param(m, MPG123_ADD_FLAGS, MPG123_IGNORE_INFOFRAME, 0.);
|
|
}
|
|
if(ret == 0) ret = do_work(m);
|
|
|
|
if(ret != 0) fprintf(stderr, "Some error occured: %s\n", mpg123_strerror(m));
|
|
|
|
|
|
mpg123_delete(m); /* Closes, too. */
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
int do_work(mpg123_handle *m)
|
|
{
|
|
int ret;
|
|
size_t count = 0;
|
|
ret = mpg123_open_fd(m, STDIN_FILENO);
|
|
if(ret != MPG123_OK) return ret;
|
|
|
|
ssize_t wret = 0;
|
|
while( !wret && (ret = mpg123_framebyframe_next(m)) == MPG123_OK || ret == MPG123_NEW_FORMAT )
|
|
{
|
|
unsigned long header;
|
|
unsigned char *bodydata;
|
|
size_t bodybytes;
|
|
if(mpg123_framedata(m, &header, &bodydata, &bodybytes) == MPG123_OK)
|
|
{
|
|
/* Need to extract the 4 header bytes from the native storage in the correct order. */
|
|
unsigned char hbuf[4];
|
|
int i;
|
|
for(i=0; i<4; ++i) hbuf[i] = (unsigned char) ((header >> ((3-i)*8)) & 0xff);
|
|
|
|
/* Now write out both header and data, fire and forget. */
|
|
wret = write(STDOUT_FILENO, hbuf, 4);
|
|
if(!wret)
|
|
wret = write(STDOUT_FILENO, bodydata, bodybytes);
|
|
fprintf(stderr, "%zu: header 0x%08lx, %zu body bytes\n", ++count, header, bodybytes);
|
|
}
|
|
}
|
|
|
|
if(ret != MPG123_DONE)
|
|
fprintf(stderr, "Some error occured (non-fatal?): %s\n", mpg123_strerror(m));
|
|
if(wret)
|
|
{
|
|
fprintf(stderr, "Write error.\n");
|
|
ret = MPG123_ERR;
|
|
}
|
|
|
|
fprintf(stderr, "Done with %zu MPEG frames.\n", count);
|
|
|
|
return 0;
|
|
}
|