CDRs contain two sub-fields to convey the audio encoding values used for the codecs used on the ingress and egress legs. For pass-through calls, the most preferred codec in the SDP answer is logged in the CDR, for a transcoded call, the selected codec is logged in the CDR. The following table shows details for the sub-fields. See CDR Field Descriptions for the full list of additional media stream statistics sub-fields.
Figure 1: Audio Encoding Sub-fields in Additional Media Stream Statistics
Sub-field Number | Sub-field Name | Max length in ASCII | Type | START | STOP | ATTEMPT | INTERMEDIATE |
|---|---|---|---|---|---|---|---|
| 5 | ingress codecParams1 | 32 | Character | NA | 256.5 | 202.5 | NA |
| 8 | egress codecParams1 | 32 | Character | NA | 256.8 | 202.8 | NA |
The two sub-fields include the following information:
network type(P for packet, C for circuit)codec type(numeric codec value, refer to Codec Type Descriptions)mode-set/bit rate
For most codecs the data appears in the format <packet_type>:<codec_type>:<mode-set/bit rate>. If more than one mode-set or bit rate value applies the values for the third component are separated by semi-colons.
For the EVS codec, only the primary mode rate is captured in CDRs and the following format applies for the sub-fields:
<packet_type>:<codec_type>:<bit-rate;mode set>
where bit-rate can be specified as a range (for example: 5.9-24.4) and mode set can contain multiple values separated by semi-colons (for example: 0-8).
For the SILK codec, the following format applies:
<packet_type>:<codec_type>:<maxaveragebitrate>
where maxaveragebitrate can be in the range 6000 to 40000.
Supported Codecs
The data applies to the following codecs/coding rates:
Table 1: Codec Types and Coding Rates
| (PSX) Codec Selections | Coding Rate (Kbps) |
|---|---|
| AMR-Bandwidth Efficient | Variable; mix of 4.75, 5.15, 5.90, 6.70, 7.40, 7.95, 10.20, 12.20 |
| AMR-Octet Aligned | Same for all AMR |
| EVRCB | 4.8, 5.8, 6.2, 6.6, 7.0, 7.5, 8.5, 9.3 |
| EVRCB0 | 4.8, 5.8, 6.2, 6.6, 7.0, 7.5, 8.5, 9.3 |
| EVS | 5.9, 7.2, 8, 9.6, 13.2, 16.4, 24.4, 32, 48, 64, 96, 128 |
| G.722 | 48, 56, 64 |
| G.722 with Silence Suppression | 48, 56, 64 |
| G.722.1 | 16, 24, 32 |
| G.722.1 with Silence Suppression | 16, 24, 32 |
| G.722.2 (AMRWB-Bandwidth Efficient) | 6.6, 8.85, 12.65, 14.25, 15.85, 18.25, 19.85, 23.05, or 23.85 |
| G.722.2 (AMRWB-Octet Aligned) | Same for all AMR-WB |
| G.723.1 | 5.3, 6.3 |
| G.723.1A | 5.3, 6.3 |
| iLBC | 13.3, 15.2 |
| iLBC with Silence Suppression | 13.3, 15.2 |
| Opus | 6 to 20 |
| SILK | 8, 12, 16, 24 |
| T.38 (version 0) | up to 14.4 |
| T.38 (version 3) | 33.6 |
Note
In the example, the first and the second columns are for illustration only, and not part of the actual decoded CDR.
The ";" (semicolon) character is used as a delimiter if more than one value applies.
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