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fdkaacenc: Implement some automatic bitrate selection

Browse source 
Based on sample rate and channel count, see
http://wiki.hydrogenaud.io/index.php?title=Fraunhofer_FDK_AAC#Recommended_Sampling_Rate_and_Bitrate_Combinations
This commit is contained in:
Sebastian Dröge 2016-08-24 19:43:55 +03:00
parent a2c03f2b00
commit 15da533580
1 changed files with 53 additions and 4 deletions
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57
ext/fdkaac/gstfdkaacenc.c
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@ -40,7 +40,7 @@ enum
PROP_BITRATE
};
#define DEFAULT_BITRATE (128000)
#define DEFAULT_BITRATE (0)
#define SAMPLE_RATES " 8000, " \
"11025, " \
@ -255,6 +255,7 @@ gst_fdkaacenc_set_format (GstAudioEncoder * enc, GstAudioInfo * info)
gint mpegversion = 4;
CHANNEL_MODE channel_mode;
AACENC_InfoStruct enc_info = { 0 };
gint bitrate;
if (self->enc) {
/* drain */
@ -362,9 +363,56 @@ gst_fdkaacenc_set_format (GstAudioEncoder * enc, GstAudioInfo * info)
return FALSE;
}
bitrate = self->bitrate;
/* See
* http://wiki.hydrogenaud.io/index.php?title=Fraunhofer_FDK_AAC#Recommended_Sampling_Rate_and_Bitrate_Combinations
*/
if (bitrate == 0) {
if (GST_AUDIO_INFO_CHANNELS (info) == 1) {
if (GST_AUDIO_INFO_RATE (info) < 16000) {
bitrate = 8000;
} else if (GST_AUDIO_INFO_RATE (info) == 16000) {
bitrate = 16000;
} else if (GST_AUDIO_INFO_RATE (info) < 32000) {
bitrate = 24000;
} else if (GST_AUDIO_INFO_RATE (info) == 32000) {
bitrate = 32000;
} else if (GST_AUDIO_INFO_RATE (info) <= 44100) {
bitrate = 56000;
} else {
bitrate = 160000;
}
} else if (GST_AUDIO_INFO_CHANNELS (info) == 2) {
if (GST_AUDIO_INFO_RATE (info) < 16000) {
bitrate = 16000;
} else if (GST_AUDIO_INFO_RATE (info) == 16000) {
bitrate = 24000;
} else if (GST_AUDIO_INFO_RATE (info) < 22050) {
bitrate = 32000;
} else if (GST_AUDIO_INFO_RATE (info) < 32000) {
bitrate = 40000;
} else if (GST_AUDIO_INFO_RATE (info) == 32000) {
bitrate = 96000;
} else if (GST_AUDIO_INFO_RATE (info) <= 44100) {
bitrate = 112000;
} else {
bitrate = 320000;
}
} else {
/* 5, 5.1 */
if (GST_AUDIO_INFO_RATE (info) < 32000) {
bitrate = 160000;
} else if (GST_AUDIO_INFO_RATE (info) <= 44100) {
bitrate = 240000;
} else {
bitrate = 320000;
}
}
}
if ((err = aacEncoder_SetParam (self->enc, AACENC_BITRATE,
self->bitrate)) != AACENC_OK) {
GST_ERROR_OBJECT (self, "Unable to set bitrate %d: %d", self->bitrate, err);
bitrate)) != AACENC_OK) {
GST_ERROR_OBJECT (self, "Unable to set bitrate %d: %d", bitrate, err);
return FALSE;
}
@ -543,7 +591,8 @@ gst_fdkaacenc_class_init (GstFdkAacEncClass * klass)
g_object_class_install_property (object_class, PROP_BITRATE,
g_param_spec_int ("bitrate",
"Bitrate",
"Target Audio Bitrate",
"Target Audio Bitrate (0 = fixed value based on "
" sample rate and channel count)",
0, G_MAXINT, DEFAULT_BITRATE,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));