# Collect information about the source content
After you have assessed the source content and have identified suitable video, audio, and captions assets in that content, you must obtain information about those assets. The information you need is different for each type of source.
You don't need this information to [create the input](medialive-inputs.md) in MediaLive. But you will need this information when you [attach the input](creating-a-channel-step2.md) to the channel in MediaLive.
**Result of this step**
After you have performed the procedures in this step, you should have source content information that looks like this example.
**Example**
[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/medialive/latest/ug/planning-content-extract.html)
**Topics**
+ [Identifying content in a CDI source](extract-contents-cdi.md)
+ [Identifying content in an AWS Elemental Link source](extract-contents-link.md)
+ [Identifying content in an HLS source](extract-contents-hls.md)
+ [Identifying content in a MediaConnect source](extract-content-emx.md)
+ [Identifying content in an MP4 source](extract-contents-mp4.md)
+ [Identifying content in an RTMP source](extract-contents-rtmp.md)
+ [Identifying content in an RTP source](extract-contents-rtp.md)
+ [Identifying content in a SMPTE 2110 source](extract-contents-s2110.md)
+ [Identifying content in an SRT source](extract-contents-srt.md)
# Identifying content in a CDI source
The content in a CDI source always consists of uncompressed video, uncompressed audio, and captions.
Obtain identifying information from the content provider.
****
[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/medialive/latest/ug/extract-contents-cdi.html)
# Identifying content in an AWS Elemental Link source
The content in an AWS Elemental Link source is always a transport stream (TS) that contains one video asset, one audio pair, and optional captions.
Obtain identifying information from the content provider.
****
[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/medialive/latest/ug/extract-contents-link.html)
Also obtain the following information about the content:
+ The maximum bitrate. You will have the option to throttle this bitrate when you set up the device in MediaLive. For more information, see [Setting up AWS Elemental Link](setup-devices.md).
+ Whether the content includes an embedded timecode. If it does, you can choose to use that timecode. For more information, see [Timecode configuration](https://docs.aws.amazon.com/medialive/latest/ug/timecode.html)[Working with timecodes and timestamps](timecode.md).
+ Whether the content includes ad avail messages (SCTE-104 messages that MediaLive will automatically convert to SCTE-35 messages). For more information about ad avail messages, see [Processing SCTE 35 messages](scte-35-message-processing.md).
# Identifying content in an HLS source
The content in an HLS container is always a transport stream (TS) that contains only one video rendition (program).
Obtain identifying information from the content provider.
****
| Asset | Details | Information to obtain |
| --- | --- | --- |
| Video | You don't need identifying information. MediaLive always extracts the single video asset. | |
| Audio | The source might include multiple audio PIDs. | Obtain the PIDs or three-character language codes of the languages that you want. We recommend that you obtain the PIDs for the audio assets. They are a more reliable way of identifying an audio asset. |
| Captions | Embedded | Obtain the languages in the channel numbers. For example, "channel 1 is French" |
# Identifying content in a MediaConnect source
The content in an AWS Elemental MediaConnect source is always a transport stream (TS). The TS is made up of one program (SPTS) or multiple programs (MPTS). Each program contains a combination of video, audio, and optional captions.
Obtain identifying information from the content provider.
****
[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/medialive/latest/ug/extract-content-emx.html)
# Identifying content in an MP4 source
The content in an MP4 source always consists of one video track, one or more audio tracks, and optional captions.
Obtain identifying information from the content provider.
****
| Asset | Details | Information to obtain |
| --- | --- | --- |
| Video | You don't need identifying information. MediaLive always extracts the single video asset. | None |
| Audio | The source might include multiple audio tracks, typically, one for each language. | Obtain the track numbers or three-character language codes of the languages that you want. |
| Captions | EmbeddedThe captions might be embedded in the video track or might be embedded in an ancillary track. | Obtain the languages in the channel numbers. For example, "channel 1 is French". |
# Identifying content in an RTMP source
This procedure applies to both RTMP push and pull inputs from the internet, and to RTMP inputs from Amazon Virtual Private Cloud. The content in an RTMP input always consists of one video, one audio, and optional captions.
Obtain identifying information from the content provider.
****
| Asset | Details | Information to obtain |
| --- | --- | --- |
| Video | You don't need identifying information. MediaLive always extracts the single video asset. | None |
| Audio | You don't need identifying information. MediaLive always extracts the single audio asset | Obtain the numbers and languages of the tracks. For example, "track 1 is French". |
| Captions | EmbeddedThe captions might be embedded in the video track or might be embedded in an ancillary track. | Obtain the languages in the channel numbers. For example, "channel 1 is French". |
# Identifying content in an RTP source
This procedure applies to both RTP inputs from the internet and inputs from Amazon Virtual Private Cloud. The content in an RTP input is always a transport stream (TS). The TS is made up of one program (SPTS) or multiple programs (MPTS). Each program contains a combination of video, a combination of audio, and optional captions.
Obtain identifying information from the content provider.
****
[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/medialive/latest/ug/extract-contents-rtp.html)
# Identifying content in a SMPTE 2110 source
The content in a SMPTE 2110 source is always a set of streams consisting of one video asset, zero or more audio assets, and zero or more captions (ancillary data) assets. Each asset is in its own stream.
Obtain identifying information from the content provider.
****
[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/medialive/latest/ug/extract-contents-s2110.html)
# Identifying content in an SRT source
The content in an SRT input is always a transport stream (TS). The TS is made up of one program (SPTS) or multiple programs (MPTS). Each program contains a combination of video, a combination of audio, and optional captions.
Obtain identifying information from the content provider.
****
[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/medialive/latest/ug/extract-contents-srt.html)