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app_mp3: Use correct buffer size and the same sample rate as the channel

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Previously, the buffer used for MP3 streamed from HTTP servers had a size of
1 MB. For 8 kHz mono audio at 16 bit resolution, such a buffer covers about 1
minute. Only when the buffer is full does audio start to play.
For MP3 files streamed from a server, that is usually not a big deal as long as
the connection to the server is fast enough to supply that much data within a
second or two. For MP3 live streams however, it takes 1 minute to download 1
minute of audio, so without this change, app_mp3 wasn't really usable for MP3
live streams.
This commit changes the buffer size so that it covers 6 seconds of an MP3 file
streamed from a server and 0.5 seconds of an MP3 live stream. The latter is
identified by the use of a .m3u file extension.

app_mp3 so far only supported 8 kHz audio.
Now it always runs at the sample rate of the channel.

ASTERISK-26085 #close

Change-Id: Id1ee274733cd804a0edecf7450329b72f1235af0
changes/40/3740/3
Michael Kuron 10 years ago
parent 27989f22f3
commit a002a4d2db
1 changed files with 37 additions and 15 deletions
Show Stats Download Patch File Download Diff File

52
apps/app_mp3.c
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@ -77,9 +77,10 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
***/
static char *app = "MP3Player";
static int mp3play(const char *filename, int fd)
static int mp3play(const char *filename, unsigned int sampling_rate, int fd)
{
int res;
char sampling_rate_str[8];
res = ast_safe_fork(0);
if (res < 0)
@ -93,30 +94,44 @@ static int mp3play(const char *filename, int fd)
dup2(fd, STDOUT_FILENO);
ast_close_fds_above_n(STDERR_FILENO);
snprintf(sampling_rate_str, 8, "%u", sampling_rate);
/* Execute mpg123, but buffer if it's a net connection */
if (!strncasecmp(filename, "http://", 7)) {
if (!strncasecmp(filename, "http://", 7) && strstr(filename, ".m3u")) {
char buffer_size_str[8];
snprintf(buffer_size_str, 8, "%u", (int) 0.5*2*sampling_rate/1000); // 0.5 seconds for a live stream
/* Most commonly installed in /usr/local/bin */
execl(LOCAL_MPG_123, "mpg123", "-q", "-s", "-b", buffer_size_str, "-f", "8192", "--mono", "-r", sampling_rate_str, "-@", filename, (char *)NULL);
/* But many places has it in /usr/bin */
execl(MPG_123, "mpg123", "-q", "-s", "-b", buffer_size_str, "-f", "8192", "--mono", "-r", sampling_rate_str, "-@", filename, (char *)NULL);
/* As a last-ditch effort, try to use PATH */
execlp("mpg123", "mpg123", "-q", "-s", "-b", buffer_size_str, "-f", "8192", "--mono", "-r", sampling_rate_str, "-@", filename, (char *)NULL);
}
else if (!strncasecmp(filename, "http://", 7)) {
char buffer_size_str[8];
snprintf(buffer_size_str, 8, "%u", 6*2*sampling_rate/1000); // 6 seconds for a remote MP3 file
/* Most commonly installed in /usr/local/bin */
execl(LOCAL_MPG_123, "mpg123", "-q", "-s", "-b", "1024", "-f", "8192", "--mono", "-r", "8000", filename, (char *)NULL);
execl(LOCAL_MPG_123, "mpg123", "-q", "-s", "-b", buffer_size_str, "-f", "8192", "--mono", "-r", sampling_rate_str, filename, (char *)NULL);
/* But many places has it in /usr/bin */
execl(MPG_123, "mpg123", "-q", "-s", "-b", "1024","-f", "8192", "--mono", "-r", "8000", filename, (char *)NULL);
execl(MPG_123, "mpg123", "-q", "-s", "-b", buffer_size_str, "-f", "8192", "--mono", "-r", sampling_rate_str, filename, (char *)NULL);
/* As a last-ditch effort, try to use PATH */
execlp("mpg123", "mpg123", "-q", "-s", "-b", "1024", "-f", "8192", "--mono", "-r", "8000", filename, (char *)NULL);
execlp("mpg123", "mpg123", "-q", "-s", "-b", buffer_size_str, "-f", "8192", "--mono", "-r", sampling_rate_str, filename, (char *)NULL);
}
else if (strstr(filename, ".m3u")) {
/* Most commonly installed in /usr/local/bin */
execl(LOCAL_MPG_123, "mpg123", "-q", "-z", "-s", "-b", "1024", "-f", "8192", "--mono", "-r", "8000", "-@", filename, (char *)NULL);
execl(LOCAL_MPG_123, "mpg123", "-q", "-z", "-s", "-f", "8192", "--mono", "-r", sampling_rate_str, "-@", filename, (char *)NULL);
/* But many places has it in /usr/bin */
execl(MPG_123, "mpg123", "-q", "-z", "-s", "-b", "1024","-f", "8192", "--mono", "-r", "8000", "-@", filename, (char *)NULL);
execl(MPG_123, "mpg123", "-q", "-z", "-s", "-f", "8192", "--mono", "-r", sampling_rate_str, "-@", filename, (char *)NULL);
/* As a last-ditch effort, try to use PATH */
execlp("mpg123", "mpg123", "-q", "-z", "-s", "-b", "1024", "-f", "8192", "--mono", "-r", "8000", "-@", filename, (char *)NULL);
execlp("mpg123", "mpg123", "-q", "-z", "-s", "-f", "8192", "--mono", "-r", sampling_rate_str, "-@", filename, (char *)NULL);
}
else {
/* Most commonly installed in /usr/local/bin */
execl(MPG_123, "mpg123", "-q", "-s", "-f", "8192", "--mono", "-r", "8000", filename, (char *)NULL);
execl(MPG_123, "mpg123", "-q", "-s", "-f", "8192", "--mono", "-r", sampling_rate_str, filename, (char *)NULL);
/* But many places has it in /usr/bin */
execl(LOCAL_MPG_123, "mpg123", "-q", "-s", "-f", "8192", "--mono", "-r", "8000", filename, (char *)NULL);
execl(LOCAL_MPG_123, "mpg123", "-q", "-s", "-f", "8192", "--mono", "-r", sampling_rate_str, filename, (char *)NULL);
/* As a last-ditch effort, try to use PATH */
execlp("mpg123", "mpg123", "-q", "-s", "-f", "8192", "--mono", "-r", "8000", filename, (char *)NULL);
execlp("mpg123", "mpg123", "-q", "-s", "-f", "8192", "--mono", "-r", sampling_rate_str, filename, (char *)NULL);
}
/* Can't use ast_log since FD's are closed */
fprintf(stderr, "Execute of mpg123 failed\n");
@ -155,6 +170,9 @@ static int mp3_exec(struct ast_channel *chan, const char *data)
} myf = {
.f = { 0, },
};
struct ast_format * native_format;
unsigned int sampling_rate;
struct ast_format * write_format;
if (ast_strlen_zero(data)) {
ast_log(LOG_WARNING, "MP3 Playback requires an argument (filename)\n");
@ -168,15 +186,19 @@ static int mp3_exec(struct ast_channel *chan, const char *data)
ast_stopstream(chan);
native_format = ast_format_cap_get_format(ast_channel_nativeformats(chan), 0);
sampling_rate = ast_format_get_sample_rate(native_format);
write_format = ast_format_cache_get_slin_by_rate(sampling_rate);
owriteformat = ao2_bump(ast_channel_writeformat(chan));
res = ast_set_write_format(chan, ast_format_slin);
res = ast_set_write_format(chan, write_format);
if (res < 0) {
ast_log(LOG_WARNING, "Unable to set write format to signed linear\n");
return -1;
}
myf.f.frametype = AST_FRAME_VOICE;
myf.f.subclass.format = ast_format_slin;
myf.f.subclass.format = write_format;
myf.f.mallocd = 0;
myf.f.offset = AST_FRIENDLY_OFFSET;
myf.f.src = __PRETTY_FUNCTION__;
@ -184,7 +206,7 @@ static int mp3_exec(struct ast_channel *chan, const char *data)
myf.f.delivery.tv_usec = 0;
myf.f.data.ptr = myf.frdata;
res = mp3play(data, fds[1]);
res = mp3play(data, sampling_rate, fds[1]);
if (!strncasecmp(data, "http://", 7)) {
timeout = 10000;
}
@ -211,7 +233,7 @@ static int mp3_exec(struct ast_channel *chan, const char *data)
res = 0;
break;
}
next = ast_tvadd(next, ast_samp2tv(myf.f.samples, 8000));
next = ast_tvadd(next, ast_samp2tv(myf.f.samples, sampling_rate));
} else {
ms = ast_waitfor(chan, ms);
if (ms < 0) {

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