H.264 Codec

Once the codec is selected in the Video Profile object the individual supported parameters of that codec can be configured. These parameters will be displayed in the SDP that is offered when negotiating the codec of a video call. Below are the parameters within the H.264 Codec that are supported on the IMG 2020. Use the H.264 Codec object to configure each of the parameters.

Web GUI Page

Dialogic > Profiles > IP Profiles > IP Profile > Video Profile (H.264) > New H.264 Codec

Maximum Objects

One H.264 codec object can be created under each Video Profile that has the Codec Type set to H264.

Field Descriptions

Payload Type (Default = 100, Range 99 - 127)

The Payload Type field displays the payload types (dynamic) ranging from 99 to 127. The payload type defines the format of the data that is passed between the IMG 2020 and the far end gateway. Select from the drop down menu the payload type of the packet being offered in the SDP from the IMG 2020 during the negotiation process. Since the payload types are all above 96 they are all dynamic payload types and are negotiated through the SDP negotiation process. Select from the drop down menu the payload type that will be offered when the H.264 codec is being negotiated with. After the negotiation process, the payload type being offered from the IMG 2020 and the payload type being offered from the far end must match in order for the call to be processed. Refer to RFC 3555 information on the payload type field.

Profile Level

The Profile Level specifies the maximum picture resolution, frame rate, and bit rate that a codec is capable of. The codec that conforms to each of the levels below is required to be capable of decoding all bitstreams encoded for that level as well as all bit streams below that level. The IMG 2020 supports the four levels displayed below. Select from drop down menu one of the required Profile Levels displayed in the table below.

Level	Max macroblock processing rate. Mbps	Max frame size Mbps	Max decoded picture size Mbps	Max video bit rate kbits/s
1.0	1485	99	396	64
1b	1485	99	396	128
1.1	3000	396	900	192
1.2	6000	396	2376	384

Profile 1.1 Resolution

The Profile 1.1 Resolution field gives the user the ability to modify the horizontal and vertical resolutions in pixels in the video signals when Profile Level 1.1 is selected from the Profile Level field above. The resolution can be modified to either CIF (Common Intermediate Format) or QCIF (Quarter CIF) at 15 frames per second. Select either QCIF or CIF from the drop down menu when the Profile Level field above is configured for Level 1.1.

CIF-15 fps (frames per second) - The CIF-15 fps selection utilizes CIF (Common Intermediate Format) which is used to standardize the horizontal and vertical resolutions in video signals (size of frame) has a resolution of 352 x 288 pixels at 15 fps.

QCIF-15 fps (frames per second) - The QCIF-15 fps selection utilizes QCIF (Quarter Common Intermediate Format) which is used to standardize the horizontal and vertical resolutions in video signals (size of frame) has a resolution of 176 x 144 pixels at 15 fps.

When Profile Level 1.0 or 1b from the Profile Level field above is selected, the resolution defaults to QCIF at 15 frames per second.

Profile 1.2 Resolution

The Profile 1.2 Resolution field gives the user the ability to modify the horizontal and vertical resolutions in pixels in the video signals when Profile Level 1.2 is selected from the Profile Level field above. The resolution can be modified to either CIF (Common Intermediate Format) at 30 frames per second or QCIF (Quarter CIF) at 15 frames per second. Select either QCIF or CIF from the drop down menu when the Profile Level field above is configured for Level 1.2.

CIF-30 fps (frames per second) - The CIF-30 fps selection utilizes CIF (Common Intermediate Format) which is used to standardize the horizontal and vertical resolutions in video signals (size of frame) has a resolution of 352 x 288 pixels at 30 fps.

CIF-15 fps (frames per second) - The CIF-15 fps selection utilizes CIF (Common Intermediate Format) which is used to standardize the horizontal and vertical resolutions in video signals (size of frame) has a resolution of 352 x 288 pixels at 15 fps.

When Profile Level 1.0 or 1b from the Profile Level field above is selected, the resolution defaults to QCIF at 15 frames per second.

Packetization Mode

The Packetization Mode field is an optional parameter which determines what packetization mode will be offered on the outgoing leg. Refer to RFC 3984 for more information on the individual fields/modes.

Not Used - The Packetization mode is not negotiated in the outgoing SDP offer.

Single NAL (Network Abstraction Layer) - Contains only a Single Network Abstraction Layer unit in the payload. The single NAL unit mode is targeted for conversational systems that comply with ITU-T Recommendation H.241. When Single NAL is selected from the drop down menu, the Single NAL parameter will be present in the outgoing SDP offer.

Not Interleaved - The non-interleaved mode is targeted for conversational systems that may not comply with ITU-T Recommendation H.241. In the non-interleaved mode NAL units are transmitted in NAL unit decoding order. When Not Interleaved is selected from the drop down menu, the Not Interleaved packetization mode parameter will be present in the outgoing SDP offer.

Interleaved - The interleaved mode is targeted for systems that do not require very low end-to-end latency. The interleaved mode allows transmission of NAL units out of NAL unit decoding order. When Interleaved is selected from the drop down menu, the Interleaved packetization mode parameter will be present in the outgoing SDP offer.

max-rcmd-nalu-size (Default = 1024)

The max-rcmd-nalu-size field is an optional parameter which signals the largest NALU (Network Abstraction Layer Units) size that the receiver can handle efficiently. The max-rcmd-nalu-size parameter value is a recommendation and not a strict upper boundary. The parameter is an integer value in the range of 0 - 4294967295 and the default value is set to 1024. To modify the max-rcmd-nalu-size parameter, highlight the value in the field and enter the new value. The max-rcmd-nalu-size value will be displayed in the outgoing SDP offer. Setting this number correctly can improve IP -to- 3G connection performance.

max-br

The max-br is an optional parameter and indicates the receiver is capable of decoding video at a higher bit rate than is required by the Profile-Level parameter. The max-br parameter is an integer indicating the max video bitrate that the receiver is capable of decoding. Select from the drop down menu the selections below.

Value in max-br field	Description
Not Used	The max-br is ignored when received and is not displayed in the outgoing SDP offer.
64	Can decode video at rate of 64 kbits/sec. The integer 64 is displayed as the max-br value in the SDP of the outgoing offer.
128	Can decode video at rate of 128 kbits/sec. The integer 128 is displayed as the max-br value in the SDP of the outgoing offer.
192	Can decode video at rate of 192 kbits/sec. The integer 192 is displayed as the max-br value in the SDP of the outgoing offer.
384	Can decode video at rate of 384 kbits/sec. The integer 384 is displayed as the max-br value in the SDP of the outgoing offer.

in-band-parameter-sets

The in-band-parameter-sets is an optional parameter which contains header information for the decoding of the video sequence.

Not Used - The in-band-parameter-sets in the sprop-parameter-sets parameter received are discarded. Therefore the sender must transmit all parameter sets in-band. The sprop-parameter-sets is not displayed in the outgoing SDP offer.

In-Band/Out-of-Band - The in-band-parameter-sets in the sprop-parameter-sets parameter received is utilized. The in-band-parameter-sets will be displayed in the SDP in the outgoing offer.

sprop-parameter-sets

The sprop-parameter-sets is an optional parameter that encodes H.264 sequence parameter set (SPS) and picture parameter set (PPS) Network Adaptation Layer NAL) units. These parameter sets provide essential information necessary to decode an H.264 bitstream; encoding them in SDP ensures that they are delivered reliably.

Not Used - When the sprop-parameter-sets optional parameter is received in the incoming offer, it is discarded. The sprop-parameter-sets parameter is not displayed in the outgoing offer.

Include Out-of-band DCI - When the sprop-parameter-sets optional parameter is received it must contain only parameter sets that conform to the Profile Level set above.