FFmpeg Map Multiple Streams to Single Stream: A Comprehensive Guide

When it comes to playing back multiple streams from a single source, having the option to select each language can be a significant advantage. One common use case is when you have a playlist of streams and want to create separate stream files for each language. In this article, we'll explore how to achieve this using FFmpeg, a powerful command-line tool for video and audio processing.

Creating Stream Files for Each Language

To begin with, let's assume you have an input file that contains multiple audio tracks. You can specify the video PID, audio PID or language, along with the URI of the stream, using the following syntax:

```bash

ffmpeg -i input -map 0:0 (encoding parameters for video) -map 0:1 (encoding parameters for audio) language=eng -map 0:2 language=fre -f mpegts udp://localhost:?

```

In this example, we're using the `-i` option to specify the input file, followed by the encoding parameters for both video and audio. The `language` option is used to specify the language of each audio track.

Combining Separate Video and Audio Streams

Another approach is to combine separate video and audio streams into a single stream for each language using FFmpeg outside of Wowza. This can be achieved using the following command:

```bash

ffmpeg -i input -map 0:0 (encoding parameters for video) -map 0:1 (encoding parameters for audio) -f mpegts udp://localhost:?

```

This command combines the separate video and audio streams into a single MPEG-TS stream, which can then be played back using Wowza.

Combining Multiple Audio Streams with FFmpeg

If you have multiple audio feeds in different languages, you can use FFmpeg to combine each audio feed with the same video feed and output three separate streams: Live Video||Live Audio 1, Live Video||Live Audio 2, and Live Video||Live Audio 3.

Here's an example command that demonstrates this:

```bash

ffmpeg -i input -map 0:0 (encoding parameters for video) -map 0:1 language=eng -map 0:2 language=fre -f mpegts udp://localhost:?

```

In this example, we're using the same syntax as before to specify the encoding parameters for both video and audio. The `language` option is used to specify the language of each audio track.

Wowza Setup

To set up Wowza to play back these multiple streams, you can create separate 'stream' files for each language, each pointing to a different audio track. You can then use these stream files to select the desired audio track when playing back the stream.

For example, if you have three audio feeds in English, French, and Spanish, you would create three separate stream files: `stream_eng`, `stream_fre`, and `stream_spa`. Each of these stream files would point to a different audio track, allowing users to select the desired language when playing back the stream.

In this article, we've explored how to use FFmpeg to map multiple streams to a single stream, creating separate stream files for each language. We've also discussed how to combine separate video and audio streams into a single MPEG-TS stream using FFmpeg outside of Wowza. By following these steps, you can create a powerful and flexible streaming solution that meets the needs of your audience.

Ffmpeg map multiple streams to single stream