--- title: Transcoding Broadcaster Input Streams slug: zixi-broadcaster-zec-current-version/transcoding-broadcaster-input-streams docTags: createdAt: 2024-12-26T16:19:04.238Z --- Once you have created the transcoding profile, you can use it to transcode an input stream. ## To Transcode an Input Stream: :::::WorkflowBlock ::::WorkflowBlockItem On the **Inputs** page of Zixi Broadcaster, click the desired row of the input stream that you want to transcode. :::hint{type="info"} Note: Multiplex inputs can be transcoded, but the output will be only the first program transcoded. ::: :::: :::WorkflowBlockItem Click the **Actions **(⚙️) button on the right end of the selected row and then click **Transcode**. ::Image[]{src="https://api.archbee.com/api/optimize/mzxtTQEvCNIdUNgF2kuwJ/I-w2E30eHkdreUAle9tAH-20260602-100433.png" size="36" width="336" height="662" darkWidth="336" darkHeight="662" position="center" alt="Transcode from Action Menu" showCaption="false"} The **Transcode \ **window with the settings of the selected input stream is displayed. ::Image[]{src="https://api.archbee.com/api/optimize/mzxtTQEvCNIdUNgF2kuwJ/qGon1d62V-DD7OFJq4yA4-20260602-100710.png" size="84" width="840" height="1240" darkWidth="840" darkHeight="1240" position="center" alt="Transcode Input Options" showCaption="false"} ::: :::WorkflowBlockItem Enter the unique **Stream ID** for the new transcoded input stream. ::: :::WorkflowBlockItem Under **Stream Parameters**, in the Video profile and Audio profile fields, do one of the following: - Select the desired Video Profile and/or Audio Profile that you have configured. - Select **Keep original stream** - if you have not configured a video or audio profile, or do not want it transcoded, or you want to set specific transcoding parameters for the specific stream. In this case, the video or audio input will not be transcoded. - Select **Remove stream** – you can use the transcoder to remove the video or audio track from the stream. ::: ::::WorkflowBlockItem If you want to merge an HTML overlay into the video stream, insert the URL for the HTML overlay into the **Dynamic Overlay URL** field. You can also select **Use HTML Audio** to merge audio from the HTML Overlay into the video stream. See the [Parameters Table](docId\:Mc8lVokobD_91PdoUU14E) below for more details. :::hint{type="warning"} Note: these fields will appear only if you have the [HTML Overlay (CEF)](docId\:NLU62V8AKjBsDCvnI63yH) plugin installed. ::: ::Image[]{src="https://api.archbee.com/api/optimize/mzxtTQEvCNIdUNgF2kuwJ/V8kjDCvPK1mH48tQGLQve-20260602-101219.png" size="90" width="840" height="1292" darkWidth="840" darkHeight="1292" position="center" alt="HTML Overlay Plugin Fields" showCaption="false"} :::: :::WorkflowBlockItem Fill in additional fields (see table below for additional parameters). ::: :::WorkflowBlockItem Click **OK**. The transcoded input stream is created and appears in an embedded window labeled Transcoded sources under the original input stream from which it was created. ::: ::::: ### Parameters Table | **Parameter** | **Description** | | -------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Stream Parameters** | | | **Force software decoding** | If the input video source comes in a 4:2:2 format, which is not supported by the Nvidia GPU decoder, select this option so the decoding will be performed on the CPU (software decoding) and the encoding will be performed on the Nvidia GPU. | | **Video Profile** | Select an existing profile, select **Keep original stream **if you do not wish to transcode the video stream, or select **Remove stream** if you want to remove the video track. | | **Audio Profile** | Select an existing profile, select **Keep original stream **if you do not wish to transcode the audio stream, or select **Remove stream** if you want to remove the audio track. | | **Apply audio profile for all audio PIDs** | Select this option if you want to re-encode all audio tracks using the same audio profile, instead of just the first audio track that is detected. | | **Output Type** | Select one of the following output types. The outputs are configured as part of the transcoding process, so there is no need to create the Output from the Zixi Broadcaster Outputs screen:
* MPEG-TS – the output will be available as MPEG Transport Stream. * NDI – the output will be available as NDI. When selecting NDI output, you can select the following video/audio profiles: - Video profile – remove stream or a Raw profile. - Audio profile - remove stream or a Raw profile. * WebRTC – the output will be available as WebRTC. When selecting NDI output, you can select the following video/audio profiles: - Video profile – remove stream, keep original stream, Raw video profile, or if the input stream is not WebRTC compliant, a transcode to WebRTC compliant profile (e.g., H.264 codec with Baseline or Main profile and no B frames). - Audio profile - remove stream, keep original stream, Raw audio profile, or if the input stream is non-Opus, transcode to Opus. | | **Transport Stream Bitrate (Kbps)** | Specify the bitrate of the transport stream. This parameter is optional. If you do not specify a TS Bitrate, the stream will be VBR. If you specify a bitrate, the stream will be CBR.
Note – CBR is recommended for downstream satellite workflows. | | **Add RTP headers** | Select this option to add RTP headers to the MPEG-TS packets. | | **Use Hardware Acceleration (if available)** | Select this checkbox to use the hardware acceleration component (e.g., NVIDIA) if it has been installed. | | **Pass all PIDs** | Select this checkbox to pass-through all non-transcoded PIDs. | | **Force I-Frames on SCTE-35 markers ** | Selecting this option will do the following:
* If an SCTE35 marker is detected and it contains a specific video timestamp (PTS), the encoder will generate an IDR-frame on the video frame with the closest or equal timestamp. * If there is no timestamp in the SCTE35 marker, the transcoder will generate an IDR frame as soon as it can. | | **Copy Closed Captions** | If the video source contains closed captions, select this option to copy the CC to the encoded video streams; otherwise, it will be dropped. This option is relevant for HEVC, H.264, and MPGV sources. Captions will be copied to HEVC and H.265 outputs, but not MPGV outputs. | | **Dynamic Overlay URL** | The URL of the HTML overlay feed. This field will be displayed **only if the CEF software was installed**.
The **HTML overlay **feature overlays a dynamic HTML page on the video stream during the transcoding process. As part of this process, the images from the HTML page are “burned” into the video.  The process uses **Chromium Embedded Framework (CEF)** to render the HTML page, and then the image is passed on to the transcoder to overlay on top of the raw video frame, which is then encoded. 
For more information, see [HTML Overlay Installation Guide](docId:6SNc7FcKnryvMtgzr06kB). | | **Use HTML Audio** | This field will be displayed **only if the HTML Overlay (CEF) software was installed**.
Select this option to merge audio from the HTML overlay into the video stream. When this option is selected, an additional **Audio PID** field will appear. The PID number you should enter depends on your intention:
* **Replace the program's audio with the overlay audio** — set the **Audio PID to the same PID the original audio uses**. The overlay audio then occupies that slot in the PMT, so any downstream receiver locked to the original audio PID gets the overlay audio instead. * **Add the overlay audio as an extra audio track alongside the original** — **pick an *unused* PID that doesn't collide with the video PID, the PCR PID, the existing audio PID(s), or the PMT PID**. Here, "arbitrary" is fine, as long as it's unique within the stream and a legal value.
To identify either the original Audio PID or an unused PID, see [Identifying the Audio PID and Other Used PIDs below](docId\:Mc8lVokobD_91PdoUU14E). | | **Smoothing Buffer (ms)** | Specify how much of the transcoded stream (in milliseconds) to store before transmitting it back to the server in order to prevent bursts.
If the **Transport stream bitrate \[kbps]** field is empty, the smoothing buffer is disabled.
If the **Transport stream bitrate \[kbps]** field is NOT empty, it is recommended to enter around 200ms, which should be enough to prevent bursts. | | ***Crop Parameters*** | Select this checkbox to set the cropping parameters. | | **Cropping Mode** | Set the units used for defining the crop. Options are: *Pixels* or *Percentages*.
Note: Depending on the type of content, in some cases, using different crop values for low-resolution outputs might be appropriate. For example, if the content includes both video content and textual content, the text would not be readable at lower resolutions and thus might be better to exclude. Another use case for using different crop values for each output would be to slice a 360 or VR input video. | | **Left, Top** | Specify the left and top positions for the crop. | | **Width x Height** | Specify the width and height values for the crop. | | ***Billing Codes*** | Billing codes are used to identify and differentiate traffic on a Zixi Broadcaster for billing purposes. When a billing code is added to a Source or Target, Zixi can track the traffic on that Broadcaster input or output separately from other inputs and outputs on the same Broadcaster. Billing codes are created by Zixi personnel on the Zixi Customer Portal for a particular organization. | | **Billing Code** | Enter the billing code that corresponds to this stream. The relevant billing can be obtained from the organization that received the billing code from Zixi. | | **Billing Password** | Enter the password that corresponds to this billing code. | | ***Enable time shift*** | | | **Maximum delay \[hh\:mm\:ss]** | Specify the time of the delayed transmission of this stream. Maximum: 24 hours. | | ***Enable multicast on pull outputs*** | Selecting this checkbox enables the transmission of this stream’s outputs as multicast. A Zixi receiver that will pull the stream will receive it in multicast. By default, Zixi Broadcaster is configured to allow transparent fallback to unicast if it is out of the LAN. Requires enabling Multicast Pull in the Settings. This setting requires enabling Multicast Pool (Settings > Multicast Pull Outputs). | | **Multicast Only** | Selecting this checkbox will force the transmission of this stream only in multicast. FEC parameters are taken from the global multicast pull outputs settings. | | ***Enable Encryption*** | Select this checkbox to encrypt the Input stream. For more information, see [Encrypting an Input Stream in Zixi Broadcaster](docId\:V3RYrBN08r4CojWl-wVoQ). | | **Encryption type (for Encryption enabled)** | Specify the type of Encryption (AES 128/192/256). | | **Encryption key (for encryption enabled)** | Click **Generate** to generate an encryption key. The generated encryption key must be sent to the end-user to decipher the received encoded stream. | | ***Recording parameters*** | Select this checkbox to customize the recording parameters. | | ***Destination Type*** | **Select the radio button for the desired storage type** and then fill in the relevant parameters**.**
* **Record to disk – **the recording is saved on the local disk. * **Record to S3** – the file is saved to your AWS S3 Bucket. | | ***Record to Disk Parameters*** | | | **File Name Template** | Specify the file name pattern that Zixi will use to generate when saving the recorded content. A separate file will be generated for each recording up to the time specified in the Max recorded file duration parameter (see above). After this duration, a new file will be generated.
The file name pattern can include any string and up to five variables listed below. Only the %T=HH.MM.SS creation time is mandatory. You can change the order of these variables and add text as long as you maintain the legitimate structure of the file in Linux and Windows:
* %S=stream id - optional. * %Y=year - optional * %M=month - optional * %D=day - optional * %T=HH.MM.SS creation time - mandatory
For example, the following pattern %Y\_recording%T.ts will generate the following file name 2017\_recording15:32:35.ts. | | **Max recorded file duration \[hours]** | Specify the maximum time allotted for recording a video stream. Default: 2 hours | | **Keep recorded files for \[hours]** | Specify the maximum time for storing the recording. Default: 0 hours | | **Custom Path** | Optionally specify a storage location for the recorded files that is relative to the root folder. This location bypasses the location specified as the root folder in the **Settings** > **General **screen. | | ***Record to S3 Parameters*** | | | **File Name Template** | Specify the file name pattern that Zixi will use to generate when saving the recorded content. A separate file will be generated for each recording up to the time specified in the Max recorded file duration parameter (see above). After this duration, a new file will be generated.
The file name pattern can include any string and up to five variables listed below. Only the %T=HH.MM.SS creation time is mandatory. You can change the order of these variables and add text as long as you maintain the legitimate structure of the file in Linux and Windows:
* %S=stream id - optional. * %Y=year - optional * %M=month - optional * %D=day - optional * %T=HH.MM.SS creation time - mandatory
For example, the following pattern %Y\_recording%T.ts will generate the following file name 2017\_recording15:32:35.ts. | | **Max recorded file duration \[hours]** | Specify the maximum time allotted for recording a video stream. Default: 2 hours | | **URL** | Specify the URL of the S3 bucket. | | **Ignore TLS certificate errors** | TLS certificate for S3 bucket might be detected as faulty if bucket name contains dot\[s]. When this option is selected, Zixi Broadcaster will ignore the TLS certificate errors and transmit the stream to its destination. | | **Access Key** | The access key that is used for accessing the S3 bucket. | | **Secret Key** | The secret key that is used for accessing the S3 bucket. | ## Identifying the Audio PID and other Used PIDs Unless you are managing the encoding of the original stream yourself and know how the PIDs are assigned, you can find them in Broadcaster by turning on [Stream Analysis](docId\:G_lSTg1_zAD2eHapLeXy7). When you open the stream analysis, what you want to look at is the Stream Information on the left side: ::Image[]{src="https://api.archbee.com/api/optimize/mzxtTQEvCNIdUNgF2kuwJ/nU4NwfhiAg99F4t9gSoJp-20260603-062858.png" size="72" width="758" height="458" position="center" alt="Stream Information" darkWidth="758" darkHeight="458" showCaption="false"} There are two things to look at here: - Programs - Unassociated PIDS When you expand the **Programs**, you will usually find one program. Expand the program, and you will see the **PMT** and **PCR** PIDs, and also **Elementary PIDs**. Now it depends on what you want to do. ### Case 1: Replace the Video's Audio Stream with Audio from the Overlay In this case, look at the **Elementary PIDs**. Technically, the audio stream can be assigned to any PID, but in normal practice, it is usually assigned to the PID following the video PID. In any case, expand them and look at the **Type** for an audio type like **AAC** or **MPEG2\_Audio**: ::Image[]{src="https://api.archbee.com/api/optimize/mzxtTQEvCNIdUNgF2kuwJ/aCqHlvMdZpvlDODPEnaC6-20260603-102937.png" size="70" width="710" height="1000" position="center" alt="Audio PID" darkWidth="710" darkHeight="1000" showCaption="false"} Since you want to replace the video's audio, **you will specify this PID number for the Overlay audio**. ### Case 2: Add the Overlay Audio without Replacing the Video's Audio In this case, you want to specify an **unused PID,** so you will want to choose a PID number that does **not** show up anywhere in the Stream Information. In other words, **avoid** the number of any of the **Elementary PIDs**, as well as the **PMT and PCR PIDs**, and the **Unassociated PIDs:** ::Image[]{src="https://api.archbee.com/api/optimize/mzxtTQEvCNIdUNgF2kuwJ/CEOeuYg-jLe-rWFk3DYJE-20260603-104330.png" size="60" width="580" height="714" position="center" alt="PIDs already in use" darkWidth="580" darkHeight="714" showCaption="false"}