def _extract_video_preview(params):
"""
This function is used to extract a standard low quality version of the provided video,
the resulting video will be in MPEG-4 format and 5fps.
@param params: Array containing all necessary function parameters
"""
auth_params = params[0]
func_params = params[1]
# detect start and final absolute paths of video resources
file_path = os.path.join(get_media_root(), func_params['file'])
preview_path = os.path.join('/tmp', str(func_params['id']) + '_preview.mp4')
token = auth_params['token']
# execute video conversion
cmd = '/usr/bin/ffmpeg -loglevel fatal -y -i "' + file_path + '" -codec:v libx264 -preset fast -movflags +faststart -strict -2 ' + preview_path
subprocess.check_output(cmd, shell=True)
# check if the preview has been generated
if not os.path.exists(preview_path):
raise Exception("Preview not generated for video item" + str(func_params['id']))
# update data about the new generated preview file
res = set_preview(func_params['id'], preview_path, 'video/mp4', token)
# remove the preview file from the local filesystem
os.remove(preview_path)
if not res:
raise Exception("Preview not generated for video item" + str(func_params['id']))
return True
def _extract_image_preview(params):
"""
This function is used to extract a standard low quality version of the provided image,
the resulting video will be in PNG format with a scaled resolution.
@param params: Array containing all necessary function parameters.
"""
auth_params = params[0]
func_params = params[1]
# create the start and final path for the image digital items
file_path = os.path.join(get_media_root(), func_params['file'])
preview_path = os.path.join('/tmp', str(func_params['id']) + 'preview.jpeg')
token = auth_params['token']
# extract image thumbnail
cmd = '/usr/bin/ffmpeg -loglevel fatal -y -i "' + file_path + '" -vf scale=-1:600 ' + preview_path
subprocess.check_output (cmd, shell=True)
# check if the preview has been created
if not os.path.exists(preview_path):
raise Exception("Preview image not generated")
# update data about the new generated preview file
res = set_preview(func_params['id'], preview_path, 'image/jpeg', token)
# remove the preview file from the local filesystem
os.remove(preview_path)
if not res:
raise Exception("Preview not generated for image item" + str(func_params['id']))
return True
def _extract_audio_preview(params):
"""
This function is used to extract a standard low quality version of the provided audio,
the resulting audio will be in MP3 format.
@param params: Array containing all necessary function parameters.
"""
auth_params = params[0]
func_params = params[1]
# create the start and final path for the audio digital items
file_path = os.path.join(settings.MEDIA_ROOT, func_params['file'])
preview_path = os.path.join('/tmp', str(func_params['id']) + 'preview.mp3')
token = auth_params['token']
# extract audio preview
cmd = '/usr/bin/ffmpeg -loglevel fatal -y -i "' + file_path + '" -ab 128k ' + preview_path
subprocess.check_output(cmd, shell=True)
# check if the preview has been created
if not os.path.exists(preview_path):
raise Exception("Audio preview not generated for item " + str(func_params['id']))
# update data about the new generated preview file
res = set_preview(func_params['id'], preview_path, 'audio/mp3', token)
# remove the preview file from the local filesystem
os.remove(preview_path)
if not res:
raise Exception("Preview not generated for audio item" + str(func_params['id']))
return True
