Generate thumbnail for inmemory uploaded video file - django

Question

The client app uploaded a video file and i need to generate a thumbnail and dump it to AWS s3 and return the client the link to the thumbnail.
I searched around and found ffmpeg fit for the purpose.
The following was the code i could come up with:
from ffmpy import FFmpeg
import tempfile
def generate_thumbnails(file_name):
output_file = tempfile.NamedTemporaryFile(suffix='.jpg', delete=False, prefix=file_name)
output_file_path = output_file.name
try:
# generate the thumbnail using the first frame of the video
ff = FFmpeg(inputs={file_name: None}, outputs={output_file_path: ['-ss', '00:00:1', '-vframes', '1']})
ff.run()
# upload generated thumbnail to s3 logic
# return uploaded s3 path
except:
error = traceback.format_exc()
write_error_log(error)
finally:
os.remove(output_file_path)
return ''
I was using django and was greeted with permission error for the above.
I found out later than ffmpeg requires the file to be on the disk and doesn't just take into account the InMemory uploaded file (I may be wrong as i assumed this).
Is there a way to read in memory video file likes normal ones using ffmpeg or should i use StringIO and dump it onto a temp. file?
I prefer not to do the above as it is an overhead.
Any alternative solution with a better benchmark also would be appreciated.
Thanks.
Update:
To save the inmemory uploaded file to disk: How to copy InMemoryUploadedFile object to disk

Answer 1

One of the possible ways i got it to work were as follows:
Steps:
a) read the InMemory uploaded file onto a temp file chunk by chunk
temp_file = tempfile.NamedTemporaryFile(suffix='.mp4', delete=False)
temp_file_path = temp_file.name
with open(temp_file_path, 'wb+') as destination:
for chunk in in_memory_file_content.chunks():
destination.write(chunk)
b) generate thumbnail using ffmpeg and subprocess
ffmpeg_command = 'ffmpeg -y -i {} -ss 00:00:01 vframes 1 {}'.format(video_file_path, thumbail_file_path
subprocess.call(ffmpeg_command, shell=True)
where,
-y is to overwrite the destination if it already exists
00:00:01 is to grab the first frame
More info on ffmpeg: https://ffmpeg.org/ffmpeg.html