pandora_cdosea/render_mlt.py

#!/usr/bin/python
import os
import time
import sys
import json

import mlt
from PyQt5 import QtWidgets

# Avoid segfault in webvfx
app = QtWidgets.QApplication(sys.argv)

mlt.mlt_log_set_level(40) # verbose
mlt.Factory.init()


tractor = mlt.Tractor()
tractor.mark_in = -1
tractor.mark_out = -1

multitrack = tractor.multitrack()

source = sys.argv[1]
target = source.replace('.json', '.xml')

with open(source) as fd:
    data = json.load(fd)

video = mlt.Playlist()
overlay = mlt.Playlist()

fps = 60
profile = mlt.Profile("atsc_1080p_%d" % fps)
#profile.set_explicit(1)

# get profile from clip
#clip = mlt.Producer(profile, 'test.mp4')
#profile.from_producer(clip)

def add_color(playlist, color, duration):
    red = mlt.Producer(profile, 'color:' + color)
    red.set_in_and_out(0, duration)
    playlist.append(red)

def add_clip(playlist, file_, in_, duration):
    if not isinstance(file_, str):
        file_ = file_.encode('utf-8')
    clip = mlt.Producer(profile, file_)
    clip.set_in_and_out(in_, in_+duration-1)
    playlist.append(clip)

def add_blank(playlist, length):
    playlist.blank(length)

def add_text(playlist, value, length):
    if not isinstance(value, str):
        value = value.encode('utf-8')
    text = mlt.Producer(profile, 'webvfx:text.html')
    text.set('transparent', 1)
    text.set('title', value)
    text.set('length', length)
    playlist.append(text)

for clip in data['clips']:
    if clip.get('black'):
        # fixme seconds to fps! duration fame etc!!
        frames = int(clip['duration'] * fps)
        add_color(video, 'black', frames)
    else:
        #print(clip['duration'], clip['path'])
        if not os.path.exists(clip['path']):
            print(clip['path'], 'is missing')
            sys.exit(1)
        # fixme seconds to fps!
        in_ = int(clip['in'] * fps)
        frames = int(clip['duration'] * fps)
        add_clip(video, clip['path'], in_, frames)

for clip in data['text']:
    if clip.get('blank'):
        frames = int(clip['duration'] * fps)
        add_blank(overlay, frames)
    else:
        frames = int(clip['duration'] * fps)
        add_text(overlay, clip['text'].upper(), frames)

multitrack.connect(video, 0)
multitrack.connect(overlay, 1)
composite = mlt.Transition(profile, "composite")
#composite.set('fill', 1)

tractor.plant_transition(composite)

consumer = 'xml'
consumer = mlt.Consumer(profile, consumer, target)
consumer.connect(tractor)
#consumer.set("real_time", -2)
consumer.start()