Dashify tile-based adaptive 360° videos

About

This tool helps you convert a 360° videos into a tile-based, quality-adaptive, MPEG-DASH streamable video. The manifest file (MPD) uses the spatial relationship description (SRD) feature, which was introduced in the second amendment of DASH standard part 1, 23009-1:2014. Click here to read more.

Installation:

sudo apt install ffmpeg # Make sure FFMpeg is installed on your computer
sudo pip3 install pybuilder
git clone https://github.com/yang-jace-liu/dash-360
cd dash-360 && pyb install

Usage:

usage: dash-360-transcode.py [-h] config input_video output_mpd

This script transcodes source video into DASH-enabled tile-based 360 videos

positional arguments:
  config       Configuration file for transcoding
  input_video  input video path
  output_mpd   output MPD path

optional arguments:
  -h, --help   show this help message and exit

Common Errors

Conflicting stream par values in Adaptation Set

All qualities for one tile should have the same aspect ratio.

Width (or Height) not divisible by 2

FFMpeg requires video width and height are even numbers. In our case, the width and height of each resolution for each tile should be even numbers.

A working example

• Download the 360° video from here, and rename it to "origin.mp4".
• We will create a DASH-streamable video containing 8 tiles (8x1), so each tile is 45°. The original resolution is 4096x2048 (4K), and we will create 3 resolutions: origin, 1080P(2160x1080), and 720P(1440x720).
• You need to give the SRD values based on it's spatial relation. Check here and here to get the meaning of each number.
• We create the following json file based on our needs, saving it as "config .json".
• Run dash-360-transcode.py config.json origin.mp4 out.mpd
• Note that tiles here have equal sizes. You may have tiles of different sizes. You can change the string values under config["qualities"][quality_name]["resolutions"] and config["qualities"][quality_name]["bitrates"] to a list of strings, and each element is correspond to a tile. You need to make sure the length of these strings are equal to the number of tiles.

{
    "tiles": [
        {
            "left": 0,
            "top": 0,
            "width": 512,
            "height": 2048
        },
        {
            "left": 512,
            "top": 0,
            "width": 512,
            "height": 2048
        },
        {
            "left": 1024,
            "top": 0,
            "width": 512,
            "height": 2048
        },
        {
            "left": 1536,
            "top": 0,
            "width": 512,
            "height": 2048
        },
        {
            "left": 2048,
            "top": 0,
            "width": 512,
            "height": 2048
        },
        {
            "left": 2560,
            "top": 0,
            "width": 512,
            "height": 2048
        },
        {
            "left": 3072,
            "top": 0,
            "width": 512,
            "height": 2048
        },
        {
            "left": 3584,
            "top": 0,
            "width": 512,
            "height": 2048
        }
    ],
    "qualities": {
        "4k": {
            "resolutions": "512x2048",
            "bitrates": "3000k"
        },
        "1080p": {
            "resolutions": "270x1080",
            "bitrates": "1500k"
        },
        "720p": {
            "resolutions": "180x720",
            "bitrates": "600k"
        }
    },
    "srd_values": [
        "0,0,0,1,1,8,1",
        "0,1,0,1,1,8,1",
        "0,2,0,1,1,8,1",
        "0,3,0,1,1,8,1",
        "0,4,0,1,1,8,1",
        "0,5,0,1,1,8,1",
        "0,6,0,1,1,8,1",
        "0,7,0,1,1,8,1"
    ],
    "keyint": 30,
    "keyint_min": 30
}