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HLS multi audio with Wowza

In this example, we are going to use Wowza to stream HLS.

You can get mode information in Wowza documentation:

If you don’t want to use Wowza, you can encode to HLS directly with ffmpeg. Please read Using ffmpeg to generate an HLS with multiple audio tracks.

As in the ffmpeg example, we will encode a video example with three audio tracks.

Our example files are:

  • video_1080p.mp4 (video source, 1920x1080)
  • audio.en.mp3 (audio file, language: english)
  • audio.es.mp3 (audio file, language: spanish)
  • audio.de.mp3 (audio file, language: german)

We will generate three video tracks with different qualities and three audio tracks. Finally we will write a smil file to use with wowza streaming server

Basic Steps

Section titled “Basic Steps”

Okay, let’s see the fundamental steps to packaging a VOD file.

  1. Create the video/audio files (with ffmpeg)

    1. read an input video and audio files from the disk.
    2. scale/resize the video to the multiple resolutions required.
    3. transcode each of the scaled videos to the required bitrates
    4. transcode the audio to the required bitrates.

  2. create a smil file that points to each of the audio/video tracks.

Now, let’s tackle this step by step, shall we?

Create the video/audio files

Section titled “Create the video/audio files”

Okay, Step 1 involves reading a video/audio file from a disk and scaling it to multiple resolutions. This can be done in a single command as follows:

ffmpeg -i video_1080p.mp4 \
-i audio.en.mp3 -i audio.es.mp3 -i audio.de.mp3 \
-filter_complex \
"[0:v]split=3[v1][v2][v3]; \
[v1]copy[v1out]; [v2]scale=w=1280:h=720[v2out]; [v3]scale=w=640:h=360[v3out]" \
-map [v1out] -c:v:0 libx264 -x264-params "nal-hrd=cbr:force-cfr=1" -b:v:0 5M -maxrate:v:0 5M -minrate:v:0 5M -bufsize:v:0 10M -preset slow -g 48 -sc_threshold 0 -keyint_min 48 hls-multiaudio-1/1080.mp4 \
-map [v2out] -c:v:1 libx264 -x264-params "nal-hrd=cbr:force-cfr=1" -b:v:1 3M -maxrate:v:1 3M -minrate:v:1 3M -bufsize:v:1 3M -preset slow -g 48 -sc_threshold 0 -keyint_min 48 hls-multiaudio-1/720.mp4 \
-map [v3out] -c:v:2 libx264 -x264-params "nal-hrd=cbr:force-cfr=1" -b:v:2 1M -maxrate:v:2 1M -minrate:v:2 1M -bufsize:v:2 1M -preset slow -g 48 -sc_threshold 0 -keyint_min 48 hls-multiaudio-1/360.mp4 \
-map 1:a:0 -c:a:0 aac -b:a:0 96k -ac 2 hls-multiaudio-1/en.mp4 \
-map 2:a:0 -c:a:1 aac -b:a:1 96k -ac 2 hls-multiaudio-1/es.mp4 \
-map 3:a:0 -c:a:2 aac -b:a:2 48k -ac 2 hls-multiaudio-1/de.mp4

This command will generate six files:

Our example files are:

  • 1080.mp4 (video source, 1920x1080)
  • 720.mp4 (video source, 1280x720)
  • 360.mp4 (video source, 640x360)
  • en.mp4 (audio file, language: english)
  • es.mp4 (audio file, language: spanish)
  • de.mp4 (audio file, language: german)

Create a smil file

Section titled “Create a smil file”

Then you need to create a smil file that points to each of the audio/video tracks.

smil file (engage-player_hls-multiaoudio-1.smil):

<?xml version="1.0" encoding="UTF-8"?>
<smil>
    <head/>
    <body>
        <switch>
                <video height="1080" src="mp4:engage-player/hls-multiaudio-1/1080" video-bitrate="5114880" width="1920">
                        <param name="videoCodecId" value="avc1.66.30" valuetype="data"/>
                        <param name="videoOnly" value="TRUE" valuetype="data"/>
                        <param name="cupertinoTag.AUDIO" value="aac" valuetype="data"/>
                        <param name="audioCodecId" value="mp4a.40.2" valuetype="data"/>
                </video>
                <video height="720" src="mp4:engage-player/hls-multiaudio-1/720" video-bitrate="332800" width="1280">
                        <param name="videoCodecId" value="avc1.66.30" valuetype="data"/>
                        <param name="videoOnly" value="TRUE" valuetype="data"/>
                        <param name="cupertinoTag.AUDIO" value="aac" valuetype="data"/>
                        <param name="audioCodecId" value="mp4a.40.2" valuetype="data"/>
                </video>
                <video height="360" src="mp4:engage-player/hls-multiaudio-1/360" video-bitrate="128000" width="640">
                        <param name="videoCodecId" value="avc1.66.30" valuetype="data"/>
                        <param name="videoOnly" value="TRUE" valuetype="data"/>
                        <param name="cupertinoTag.AUDIO" value="aac" valuetype="data"/>
                        <param name="audioCodecId" value="mp4a.40.2" valuetype="data"/>
                </video>
                <video src="mp4:engage-player/hls-multiaudio-1/en" system-language="en" title="English" audio-bitrate="99328">
                        <param name="audioOnly" value="TRUE" valuetype="data"/>
                        <param name="cupertinoTag" value="EXT-X-MEDIA" valuetype="data"/>
                        <param name="cupertinoTag.GROUP-ID" value="aac" valuetype="data"/>
                        <param name="cupertinoTag.DEFAULT" value="YES" valuetype="data"/>
                        <param name="cupertinoTag.AUTOSELECT" value="YES" valuetype="data"/>
                </video>
                <video src="mp4:engage-player/hls-multiaudio-1/es" system-language="es" title="Español" audio-bitrate="99328">
                        <param name="audioOnly" value="TRUE" valuetype="data"/>
                        <param name="cupertinoTag" value="EXT-X-MEDIA" valuetype="data"/>
                        <param name="cupertinoTag.GROUP-ID" value="aac" valuetype="data"/>
                        <param name="cupertinoTag.DEFAULT" value="NO" valuetype="data"/>
                        <param name="cupertinoTag.AUTOSELECT" value="YES" valuetype="data"/>
                </video>
                <video src="mp4:engage-player/hls-multiaudio-1/de" system-language="de" title="Deutsch" audio-bitrate="99328">
                        <param name="audioOnly" value="TRUE" valuetype="data"/>
                        <param name="cupertinoTag" value="EXT-X-MEDIA" valuetype="data"/>
                        <param name="cupertinoTag.GROUP-ID" value="aac" valuetype="data"/>
                        <param name="cupertinoTag.DEFAULT" value="NO" valuetype="data"/>
                        <param name="cupertinoTag.AUTOSELECT" value="YES" valuetype="data"/>
                </video>


        </switch>
    </body>
</smil>

Copy the files to your Wowza installation

Section titled “Copy the files to your Wowza installation”

You will need to copy those files to your Wowza installation to play your videos.

This is the folder structure in the example. Yours can be different.

\  (wowza root app)
|- engage-player_hls-multiaoudio-1.smil
|- engage-player\
   |- hls-multiaudio-1\
      |- 1080.mp4
      |- 720.mp4
      |- 360.mp4
      |- en.mp4
      |- es.mp4
      |- de.mp4

Now, You can point to your m3u8 file using the URL: https://<wowza.server>/<your_app_name>/smil:engage-player_hls-multiaoudio-1.smil/playlist.m3u8