Changeset 3083 for pjproject/trunk/pjmedia/include/pjmedia-codec/ipp_codecs.h

Timestamp:

Jan 29, 2010 3:51:09 PM (14 years ago)

Author:

nanang

Message:

Ticket #1028:

• Updated codecs docs, more detail info about codec settings.

File:

• pjproject/trunk/pjmedia/include/pjmedia-codec/ipp_codecs.h (modified) (1 diff)

pjproject/trunk/pjmedia/include/pjmedia-codec/ipp_codecs.h

@@ -34 +34 @@
  * @{
  *
- * This section describes functions to register and register IPP codec
+ * This section describes functions to initialize and register IPP codec
  * factory to the codec manager. After the codec factory has been registered,
  * application can use @ref PJMEDIA_CODEC API to manipulate the codec.
- * This codec factory contains various codecs, e.g: G.729, G.723.1, G.726, 
- * G.728, G.722.1, AMR.
+ *
+ * This codec factory contains various codecs, i.e: G.729, G.723.1, G.726, 
+ * G.728, G.722.1, AMR, and AMR-WB.
+ *
+ *
+ * \section pjmedia_codec_ipp_g729 IPP G.729
+ *
+ * IPP G.729 is compliant with ITU-T G.729 and Annexes A, B, C, C+, D, 
+ * E, I specifications. However, currently the pjmedia implementation is
+ * using Annexes A and B only.
+ *
+ * IPP G.729 supports 16-bit PCM audio signal with sampling rate 8000Hz, 
+ * frame length 10ms, and resulting in bitrate 8000bps (annexes D and E
+ * introduce bitrates 6400bps and 11800bps).
+ *
+ * \subsection codec_setting Codec Settings
+ *
+ * General codec settings for this codec such as VAD and PLC can be 
+ * manipulated through the <tt>setting</tt> field in #pjmedia_codec_param. 
+ * Please see the documentation of #pjmedia_codec_param for more info.
+ *
+ * Note that G.729 VAD status should be signalled in SDP, see more
+ * description below.
+ *
+ * \subsubsection annexb Annex B
+ *
+ * The capability of VAD/DTX is specified in Annex B.
+ *
+ * By default, Annex B is enabled. This default setting of Annex B can 
+ * be modified using #pjmedia_codec_mgr_set_default_param().
+ *
+ * In #pjmedia_codec_param, Annex B is configured via VAD setting and
+ * format parameter "annexb" in the SDP "a=fmtp" attribute in
+ * decoding fmtp field. Valid values are "yes" and "no",
+ * the implementation default is "yes". When this parameter is omitted
+ * in the SDP, the value will be "yes" (RFC 4856 Section 2.1.9).
+ *
+ * Here is an example of modifying default setting of Annex B to
+ * be disabled using #pjmedia_codec_mgr_set_default_param():
+ \code
+    pjmedia_codec_param param;
+
+    pjmedia_codec_mgr_get_default_param(.., &param);
+    ...
+    // Set VAD
+    param.setting.vad = 0;
+    // Set SDP format parameter
+    param.setting.dec_fmtp.cnt = 1;
+    param.setting.dec_fmtp.param[0].name = pj_str("annexb");
+    param.setting.dec_fmtp.param[0].val  = pj_str("no");
+    ...
+    pjmedia_codec_mgr_set_default_param(.., &param);
+ \endcode
+ *
+ * \note
+ * The difference of Annex B status in SDP offer/answer may be considered as 
+ * incompatible codec in SDP negotiation.
+ *
+ * 
+ * \section pjmedia_codec_ipp_g7231 IPP G.723.1
+ *
+ * IPP G.723.1 speech codec is compliant with ITU-T G.723.1 and Annex A
+ * specifications.
+ *
+ * IPP G.723.1 supports 16-bit PCM audio signal with sampling rate 8000Hz, 
+ * frame length 30ms, and resulting in bitrates 5300bps and 6300bps.
+ *
+ * By default, pjmedia implementation uses encoding bitrate of 6300bps.
+ * The bitrate is signalled in-band in G.723.1 frames and interoperable.
+ *
+ * \subsection codec_setting Codec Settings
+ *
+ * General codec settings for this codec such as VAD and PLC can be 
+ * manipulated through the <tt>setting</tt> field in #pjmedia_codec_param. 
+ * Please see the documentation of #pjmedia_codec_param for more info.
+ *
+ *
+ * \section pjmedia_codec_ipp_g726 IPP G.726
+ *
+ * IPP G.726 is compliant with ITU-T G.726 and G.726 Annex A specifications.
+ *
+ * IPP G.726 supports 16-bit PCM audio signal with sampling rate 8000Hz,
+ * 10ms frame length and producing 16kbps, 24kbps, 32kbps, 48kbps bitrates.
+ * The bitrate is specified explicitly in its encoding name, i.e: G726-16,
+ * G726-24, G726-32, G726-48.
+ *
+ * \subsection codec_setting Codec Settings
+ *
+ * General codec settings for this codec such as VAD and PLC can be 
+ * manipulated through the <tt>setting</tt> field in #pjmedia_codec_param. 
+ * Please see the documentation of #pjmedia_codec_param for more info.
+ *
+ *
+ * \section pjmedia_codec_ipp_g728 IPP G.728
+ *
+ * IPP G.728 is compliant with ITU-T G.728 with I, G, H Appendixes 
+ * specifications for Low-Delay CELP coder.
+ * 
+ * IPP G.728 supports 16-bit PCM audio signal with sampling rate 8000Hz,
+ * 20ms frame length and producing 9.6kbps, 12.8kbps, and 16kbps bitrates.
+ *
+ * The pjmedia implementation currently uses 16kbps bitrate only.
+ *
+ * \subsection codec_setting Codec Settings
+ *
+ * General codec settings for this codec such as VAD and PLC can be 
+ * manipulated through the <tt>setting</tt> field in #pjmedia_codec_param. 
+ * Please see the documentation of #pjmedia_codec_param for more info.
+ *
+ *
+ * \section pjmedia_codec_ipp_g7221 IPP G.722.1
+ *
+ * The pjmedia implementation of IPP G.722.1 supports 16-bit PCM audio 
+ * signal with sampling rate 16000Hz, 20ms frame length and producing 
+ * 16kbps, 24kbps, and 32kbps bitrates.
+ *
+ * \subsection codec_setting Codec Settings
+ *
+ * General codec settings for this codec such as VAD and PLC can be 
+ * manipulated through the <tt>setting</tt> field in #pjmedia_codec_param. 
+ * Please see the documentation of #pjmedia_codec_param for more info.
+ *
+ * \subsubsection bitrate Bitrate
+ *
+ * The codec implementation supports only standard bitrates, i.e:
+ * 24kbps and 32kbps. Both are enabled by default.
+ *
+ * \remark
+ * There is a flaw in the codec manager as currently it could not 
+ * differentiate G.722.1 codecs by bitrates, hence invoking 
+ * #pjmedia_codec_mgr_set_default_param() may only affect a G.722.1 codec
+ * with the highest priority (or first index found in codec enumeration 
+ * when they have same priority) and invoking
+ * #pjmedia_codec_mgr_set_codec_priority() will set priority of all G.722.1
+ * codecs with sampling rate as specified.
+ *
+ *
+ * \section pjmedia_codec_ipp_amr IPP AMR
+ *
+ * The IPP AMR is compliant with GSM06.90-94 specifications for GSM Adaptive
+ * Multi-Rate codec.
+ *
+ * IPP AMR supports 16-bit PCM audio signal with sampling rate 8000Hz,
+ * 20ms frame length and producing various bitrates that ranges from 4.75kbps
+ * to 12.2kbps.
+ *
+ * \subsection codec_setting Codec Settings
+ *
+ * General codec settings for this codec such as VAD and PLC can be 
+ * manipulated through the <tt>setting</tt> field in #pjmedia_codec_param. 
+ * Please see the documentation of #pjmedia_codec_param for more info.
+ *
+ * \subsubsection bitrate Bitrate
+ *
+ * By default, encoding bitrate is 7400bps. This default setting can be 
+ * modified using #pjmedia_codec_mgr_set_default_param() by specifying 
+ * prefered AMR bitrate in field <tt>info::avg_bps</tt> of 
+ * #pjmedia_codec_param. Valid bitrates could be seen in 
+ * #pjmedia_codec_amrnb_bitrates.
+ *
+ * \subsubsection payload_format Payload Format
+ *
+ * There are two AMR payload format types, bandwidth-efficient and
+ * octet-aligned. Default setting is using octet-aligned. This default payload
+ * format can be modified using #pjmedia_codec_mgr_set_default_param().
+ *
+ * In #pjmedia_codec_param, payload format can be set by specifying SDP 
+ * format parameters "octet-align" in the SDP "a=fmtp" attribute for 
+ * decoding direction. Valid values are "0" (for bandwidth efficient mode)
+ * and "1" (for octet-aligned mode).
+ *
+ * \subsubsection mode_set Mode-Set
+ * 
+ * Mode-set is used for restricting AMR modes in decoding direction.
+ *
+ * By default, no mode-set restriction applied. This default setting can be 
+ * be modified using #pjmedia_codec_mgr_set_default_param().
+ *
+ * In #pjmedia_codec_param, mode-set could be specified via format parameters
+ * "mode-set" in the SDP "a=fmtp" attribute for decoding direction. Valid 
+ * value is a comma separated list of modes from the set 0 - 7, e.g: 
+ * "4,5,6,7". When this parameter is omitted, no mode-set restrictions applied.
+ *
+ * Here is an example of modifying AMR default codec param:
+ \code
+    pjmedia_codec_param param;
+
+    pjmedia_codec_mgr_get_default_param(.., &param);
+    ...
+    // set default encoding bitrate to the highest 12.2kbps
+    param.info.avg_bps = 12200;
+
+    // restrict decoding bitrate to 10.2kbps and 12.2kbps only
+    param.setting.dec_fmtp.param[0].name = pj_str("mode-set");
+    param.setting.dec_fmtp.param[0].val  = pj_str("6,7");
+
+    // also set to use bandwidth-efficient payload format
+    param.setting.dec_fmtp.param[1].name = pj_str("octet-align");
+    param.setting.dec_fmtp.param[1].val  = pj_str("0");
+
+    param.setting.dec_fmtp.cnt = 2;
+    ...
+    pjmedia_codec_mgr_set_default_param(.., &param);
+ \endcode
+ * 
+ *
+ * \section pjmedia_codec_ipp_amrwb IPP AMR-WB
+ *
+ * The IPP AMR-WB is compliant with 3GPP TS 26.190-192, 194, 201 
+ * specifications for Adaptive Multi-Rate WideBand codec.
+ *
+ * IPP AMR-WB supports 16-bit PCM audio signal with sampling rate 16000Hz,
+ * 20ms frame length and producing various bitrates. Valid bitrates could be
+ * seen in #pjmedia_codec_amrwb_bitrates. The pjmedia implementation default
+ * bitrate is 15850bps.
+ *
+ * \subsection codec_setting Codec Settings
+ *
+ * General codec settings for this codec such as VAD and PLC can be 
+ * manipulated through the <tt>setting</tt> field in #pjmedia_codec_param. 
+ * Please see the documentation of #pjmedia_codec_param for more info.
+ *
+ * \subsubsection bitrate Bitrate
+ *
+ * By default, encoding bitrate is 15850bps. This default setting can be 
+ * modified using #pjmedia_codec_mgr_set_default_param() by specifying 
+ * prefered AMR bitrate in field <tt>info::avg_bps</tt> of 
+ * #pjmedia_codec_param.
+ *
+ * \subsubsection payload_format Payload Format
+ *
+ * There are two AMR payload format types, bandwidth-efficient and
+ * octet-aligned. Default setting is using octet-aligned. This default payload
+ * format can be modified using #pjmedia_codec_mgr_set_default_param().
+ *
+ * In #pjmedia_codec_param, payload format can be set by specifying SDP 
+ * format parameters "octet-align" in the SDP "a=fmtp" attribute for 
+ * decoding direction. Valid values are "0" (for bandwidth efficient mode)
+ * and "1" (for octet-aligned mode).
+ *
+ * \subsubsection mode_set Mode-Set
+ * 
+ * Mode-set is used for restricting AMR modes in decoding direction.
+ *
+ * By default, no mode-set restriction applied. This default setting can be 
+ * be modified using #pjmedia_codec_mgr_set_default_param().
+ *
+ * In #pjmedia_codec_param, mode-set could be specified via format parameters
+ * "mode-set" in the SDP "a=fmtp" attribute for decoding direction. Valid 
+ * value is a comma separated list of modes from the set 0 - 7, e.g: 
+ * "4,5,6,7". When this parameter is omitted, no mode-set restrictions applied.
  */