Multibitrate HLS

[vintagefilm]

I am working on the demo version for now. Trying to figure out how to do multi-bitrate HLS. I can't really find anything in the manual that helps. Can someone point me to a tutorial or post here some kind of help getting started.

I have made a nice start and have a single stream figured out. Thankds for your help!

--Grace McKay

[Frank Schoenberger]

Hello Grace, 

You are right, there is unfortunately, no tutorial yet that shows how to create multi-bitrate HLS. I will try to draft something up for this that we can post on the MainConcept website. Here is some basic description that hopefully allows you to already start with it now.

You can create multi-bitrate by using the Batch List option in TotalCode Studio:

1. Open the input file and drag it to the Output section in TotalCode Studio.
   
2. Then select the HLS preset for the first layer
   
3. Configure the encoding settings as needed 
   
4. Select the location for the output and give it a proper name
   
5. Click the "Add job from GUI to the batch job list" button
   
6. Repeat the steps 2 - 5 for any further layers
   
7. Once you are done, click the "Show Batch Jobs" button
   
8. In the Batch List dialog, click the "Start" button so that TotalCode Studio starts transcoding all HLS layers
   
9. When the transcoding is done, you can create the master playlist for the HLS layers. Go to "Tools > Create master playlist/manifest… > Create Apple HLS Master Playlist".     
   
10. In the dialog you can select the HLS media segment metadata (“meta”) files created by TotalCode Studio to create a master playlist file. Click the "Add" button to browse for the corresponding meta files.
    
11. Click "Create" to generate the manifest or master playlist file.
    

Now you have a complete HLS layer set, including a master playlist file.

[vintagefilm]

thank you. I am trying this and cannot get past this message "There exists a job with this output file name. Please select a different output file"

so the question is - How do I do that?

[Hiroyuki Komatsu]

Hello Grace,

When you repeat step 2-5, you are repeating for the each layers you want to produce in the result.
You need to give identical output filename to the each layer. Output filename can be set in the edit box located at the bottom of the application window.
   
For example, you can name the each output file with individual levels as _low, _mid, _high or _level1, _level2 etc..

Hiroyuki Komatsu
App Support
MainConcept

[vintagefilm]

Thank you. That helped a lot. I was able to get through the encoding. I am now uploading the files created to see if my player can access and play them back. I am surprised to find all of the different bitrate files in the same folder. The other options I have seen separate them into there own folders, say a 720 folder and a 1080 folder.

[Hiroyuki Komatsu]

Hello Grace,

Yes, technically it's possible to put each layer into different folder.

For example:
D:/hls_output/low/stream.m3u8
D:/hls_output/med/stream.m3u8
D:/hls_output/high/stream.m3u8
And refer to them in the master playlist D:/hls_output/master.m3u8

However, this is currently not supported in TotalCodeStudio. The master playlist will not have reference to the stream.m3u8 placed in subfolders.
If you are familiar with M3U8 metadata, there is a temporary workaround modifying the master.m3u8 as below:

Assuming you have HLS sub folders as above example.
1. Open master.m3u8 file with a text editor.
2. Modify the reference to the metadata as below:
*The texts in bold were inserted.
#EXT-X-STREAM-INF:BANDWIDTH=1365300,AVERAGE-BANDWIDTH=1322303,FRAME-RATE=29.97,CODECS="mp4a.40.2,avc1.64001e",RESOLUTION=768x432,VIDEO="video_group"
low/stream.ts.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=2281488,AVERAGE-BANDWIDTH=2251631,FRAME-RATE=29.97,CODECS="mp4a.40.2,avc1.64001f",RESOLUTION=960x540,VIDEO="video_group"
med/stream.ts.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=8221741,AVERAGE-BANDWIDTH=8163533,FRAME-RATE=29.97,CODECS="mp4a.40.2,avc1.640028",RESOLUTION=1920x1080,VIDEO="video_group"
high/stream.ts.m3u8

Now the master play list has reference to stream.m3u8 placed in each subfolder. 

Usage of subfolders must be useful for other customers too. I’ll pitch it to the team and see what they think about adding this ability.

Hiroyuki Komatsu
App Support
MainConcept