diff options
Diffstat (limited to 'modules/mpa/mpa.c')
| -rw-r--r-- | modules/mpa/mpa.c | 111 |
1 files changed, 59 insertions, 52 deletions
diff --git a/modules/mpa/mpa.c b/modules/mpa/mpa.c index 04a6a8c..88ebfbe 100644 --- a/modules/mpa/mpa.c +++ b/modules/mpa/mpa.c @@ -16,7 +16,7 @@ * * The mpa audio codec * - * Supported version: + * Supported version: * libmpg123 1.16.0 or later * libtwolame 0.3.13 or later * @@ -36,35 +36,35 @@ Required parameters: None Optional parameters: - layer: which layer of MPEG audio encoding; permissible values - are 1, 2, 3. + layer: which layer of MPEG audio encoding; permissible values + are 1, 2, 3. - samplerate: the rate at which audio is sampled. MPEG-1 audio - supports sampling rates of 32, 44.1, and 48 kHz; MPEG-2 - supports sampling rates of 16, 22.05 and 24 kHz. This parameter - is separate from the RTP timestamp clock rate which is always - 90000 Hz for MPA. + samplerate: the rate at which audio is sampled. MPEG-1 audio + supports sampling rates of 32, 44.1, and 48 kHz; MPEG-2 + supports sampling rates of 16, 22.05 and 24 kHz. This parameter + is separate from the RTP timestamp clock rate which is always + 90000 Hz for MPA. - mode: permissible values are "stereo", "joint_stereo", - "single_channel", "dual_channel". The "channels" parameter - does not apply to MPA. It is undefined to put a number of - channels in the SDP rtpmap attribute for MPA. + mode: permissible values are "stereo", "joint_stereo", + "single_channel", "dual_channel". The "channels" parameter + does not apply to MPA. It is undefined to put a number of + channels in the SDP rtpmap attribute for MPA. - bitrate: the data rate for the audio bit stream. + bitrate: the data rate for the audio bit stream. - ptime: RECOMMENDED duration of each packet in milliseconds. + ptime: RECOMMENDED duration of each packet in milliseconds. - maxptime: maximum duration of each packet in milliseconds. + maxptime: maximum duration of each packet in milliseconds. - Parameters which are omitted are left to the encoder to choose - based on the session bandwidth, configuration information, or - other constraints. The selected layer as well as the sampling - rate and mode are indicated in the payload so receivers can - process the data without these parameters being specified - externally. + Parameters which are omitted are left to the encoder to choose + based on the session bandwidth, configuration information, or + other constraints. The selected layer as well as the sampling + rate and mode are indicated in the payload so receivers can + process the data without these parameters being specified + externally. Encoding considerations: - This type is only defined for transfer via RTP [RFC 3550]. + This type is only defined for transfer via RTP [RFC 3550]. Security considerations: See Section 5 of RFC 3555 @@ -73,16 +73,17 @@ Published specification: RFC 3551 Applications which use this media type: - Audio and video streaming and conferencing tools. + Audio and video streaming and conferencing tools. */ static struct aucodec mpa = { - .pt = NULL, + .pt = NULL, /* for the time being, to cope +with AVT AC1 interop problems, we do not use "14" here */ .name = "MPA", .srate = 90000, - .ch = 1, + .ch = 1, .fmtp = "", .encupdh = mpa_encode_update, .ench = mpa_encode_frm, @@ -100,30 +101,31 @@ static int module_init(void) int res; /** generate fmtp string based on config file */ - + strcpy(mode,mpa.fmtp); if (0 == conf_get_u32(conf, "mpa_bitrate", &value)) { - if(value<8000 || value>384000) { - error("MPA bitrate between 8000 and 384000 are allowed."); + if (value<8000 || value>384000) { + error("MPA bitrate between 8000 and " + "384000 are allowed."); return -1; } - (void)re_snprintf(fmtp+strlen(fmtp), sizeof(fmtp)-strlen(fmtp), - "; bitrate=%d", - value); + (void)re_snprintf(fmtp+strlen(fmtp), + sizeof(fmtp)-strlen(fmtp), + "; bitrate=%d", value); } if (0 == conf_get_u32(conf, "mpa_layer", &value)) { - if(value<1 || value>4) { + if (value<1 || value>4) { error("MPA layer 1, 2 or 3 are allowed."); return -1; } - (void)re_snprintf(fmtp+strlen(fmtp), sizeof(fmtp)-strlen(fmtp), - "; layer=%d", - value); + (void)re_snprintf(fmtp+strlen(fmtp), + sizeof(fmtp)-strlen(fmtp), + "; layer=%d", value); } if (0 == conf_get_u32(conf, "mpa_samplerate", &value)) { - switch(value) { + switch (value) { case 32000: case 44100: case 48000: @@ -132,40 +134,45 @@ static int module_init(void) case 24000: break; default: - error("MPA samplerates of 16, 22.05, 24, 32, 44.1, and 48 kHz are allowed."); + error("MPA samplerates of 16, 22.05, 24, 32, " + "44.1, and 48 kHz are allowed."); return -1; } - (void)re_snprintf(fmtp+strlen(fmtp), sizeof(fmtp)-strlen(fmtp), - "; samplerate=%d", - value); + (void)re_snprintf(fmtp+strlen(fmtp), + sizeof(fmtp)-strlen(fmtp), + "; samplerate=%d", value); } if (0 == conf_get_str(conf, "mpa_mode", mode, sizeof(mode))) { char *p = mode; - while(*p) { + while (*p) { *p = tolower(*p); - p++; + ++p; } - - if(strcmp(mode,"stereo") && strcmp(mode,"joint_stereo") && strcmp(mode,"single_channel") && strcmp(mode,"dual_channel")) { - error("MPA mode: Permissible values are stereo, joint_stereo, single_channel, dual_channel"); + + if (strcmp(mode,"stereo") + && strcmp(mode,"joint_stereo") + && strcmp(mode,"single_channel") + && strcmp(mode,"dual_channel")) { + error("MPA mode: Permissible values are stereo, " + "joint_stereo, single_channel, dual_channel"); return -1; } - - (void)re_snprintf(fmtp+strlen(fmtp), sizeof(fmtp)-strlen(fmtp), - "; mode=%s", - mode); + (void)re_snprintf(fmtp+strlen(fmtp), + sizeof(fmtp)-strlen(fmtp), + "; mode=%s", mode); } - if(fmtp[0]==';' && fmtp[1]==' ') + if (fmtp[0]==';' && fmtp[1]==' ') mpa.fmtp = fmtp+2; else mpa.fmtp = fmtp; /* init decoder library */ res = mpg123_init(); - if(res != MPG123_OK) { - error("MPA libmpg123 init error %s", mpg123_plain_strerror(res)); + if (res != MPG123_OK) { + error("MPA libmpg123 init error %s", + mpg123_plain_strerror(res)); return -1; } |