WIP: Adds mediainfo sniffing and auto-thumbnailing with ffmpeg.

README.md

@@ -169,6 +169,19 @@ class BlogPageWithMedia(Page):
     ]
 ```
 
+## Sniffing media metadata and auto-thumbnails
+
+If you have `ffprobe` (via ffmpeg) installed (and specify the command path in
+settings), it can sniff the media file to auto-populate duration, height and
+width.
+
+    WAGTAILMEDIA_FFPROBE_CMD = '/usr/local/bin/ffprobe'
+
+Additionaly, `ffmpeg` can extract a frame from a video file to auto-generate a
+thumbnail. Just set the path to ffmpeg in settings.
+
+    WAGTAILMEDIA_FFMPEG_CMD = '/usr/local/bin/ffmpeg'
+
 
 ## How to run tests
 

wagtailmedia/migrations/0004_add_mediainfo.py

@@ -0,0 +1,25 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.8 on 2017-12-29 18:36
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('wagtailmedia', '0003_copy_media_permissions_to_collections'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='media',
+            name='mediainfo',
+            field=models.TextField(blank=True, null=True, verbose_name='mediainfo'),
+        ),
+        migrations.AlterField(
+            model_name='media',
+            name='duration',
+            field=models.PositiveIntegerField(blank=True, help_text='Duration in seconds', null=True, verbose_name='duration'),
+        ),
+    ]

wagtailmedia/models.py

@@ -4,9 +4,10 @@
 
 from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
+from django.core.files import File
 from django.core.urlresolvers import reverse
 from django.db import models
-from django.db.models.signals import pre_delete
+from django.db.models.signals import post_save, pre_delete
 from django.dispatch import Signal
 from django.dispatch.dispatcher import receiver
 from django.utils.encoding import python_2_unicode_compatible
@@ -18,6 +19,10 @@
 from wagtail.wagtailsearch import index
 from wagtail.wagtailsearch.queryset import SearchableQuerySetMixin
 
+from .sniffers.ffmpeg import (
+    generate_media_thumb, get_video_stream_data, sniff_media_data
+)
+
 
 class MediaQuerySet(SearchableQuerySetMixin, models.QuerySet):
     pass
@@ -34,11 +39,14 @@ class AbstractMedia(CollectionMember, index.Indexed, models.Model):
     file = models.FileField(upload_to='media', verbose_name=_('file'))
 
     type = models.CharField(choices=MEDIA_TYPES, max_length=255, blank=False, null=False)
-    duration = models.PositiveIntegerField(verbose_name=_('duration'), help_text=_('Duration in seconds'))
+    duration = models.PositiveIntegerField(blank=True, null=True, verbose_name=_('duration'),
+                                           help_text=_('Duration in seconds'))
     width = models.PositiveIntegerField(null=True, blank=True, verbose_name=_('width'))
     height = models.PositiveIntegerField(null=True, blank=True, verbose_name=_('height'))
     thumbnail = models.FileField(upload_to='media_thumbnails', blank=True, verbose_name=_('thumbnail'))
 
+    mediainfo = models.TextField(null=True, blank=True, verbose_name=_('mediainfo'))
+
     created_at = models.DateTimeField(verbose_name=_('created at'), auto_now_add=True)
     uploaded_by_user = models.ForeignKey(
         settings.AUTH_USER_MODEL,
@@ -92,6 +100,18 @@ def is_editable_by_user(self, user):
         from wagtailmedia.permissions import permission_policy
         return permission_policy.user_has_permission_for_instance(user, 'change', self)
 
+    def save(self, *args, **kwargs):
+        ''' Send changed field names through to signals. '''
+        if self.pk is not None:
+            old = self.__class__._default_manager.filter(pk=self.pk).values()[0]
+            changed = []
+            for field in old.keys():
+                if getattr(self, field) != old[field]:
+                    changed.append(field)
+            if changed:
+                kwargs['update_fields'] = changed
+        super(AbstractMedia, self).save(*args, **kwargs)
+
     class Meta:
         abstract = True
         verbose_name = _('media')
@@ -130,6 +150,31 @@ def get_media_model():
     return media_model
 
 
+# Receive the post_save signal and sniff mediainfo data if possible.
+@receiver(post_save, sender=Media)
+def media_sniff(sender, instance, created, update_fields, **kwargs):
+    if hasattr(settings, 'WAGTAILMEDIA_FFPROBE_CMD'):
+        if created or (update_fields and 'file' in update_fields):
+            data = sniff_media_data(instance.file.path)
+            if data:
+                duration = int(float(data['format']['duration']))
+                Media.objects.filter(pk=instance.pk).update(duration=duration, mediainfo=data)
+                if instance.type == 'video':
+                    video_stream = get_video_stream_data(data)
+                    if video_stream:
+                        height = int(float(video_stream['height']))
+                        width = int(float(video_stream['width']))
+                        Media.objects.filter(pk=instance.pk).update(height=height, width=width)
+
+                    # Try to scrape a thumbnail from video
+                    if hasattr(settings, 'WAGTAILMEDIA_FFMPEG_CMD')\
+                            and not instance.thumbnail:
+                        thumb_path = generate_media_thumb(instance.file.path, f'{instance.file.name}.jpg',
+                                                          skip_seconds=int(duration*1.0/2))
+                        instance.thumbnail.save(os.path.basename(thumb_path), File(open(thumb_path, 'rb')))
+                        os.remove(thumb_path)
+
+
 # Receive the pre_delete signal and delete the file associated with the model instance.
 @receiver(pre_delete, sender=Media)
 def media_delete(sender, instance, **kwargs):

wagtailmedia/sniffers/ffmpeg.py

@@ -0,0 +1,41 @@
+from __future__ import unicode_literals
+
+import json
+import subprocess
+import sys
+
+from django.conf import settings
+
+
+def sniff_media_data(video_path):
+    ''' Uses ffprobe to sniff mediainfo metadata. '''
+    ffprobe = settings.WAGTAILMEDIA_FFPROBE_CMD
+    p = subprocess.check_output([ffprobe, "-v", "quiet", "-print_format", "json", "-show_format", "-show_streams",
+                                 video_path])
+    return json.loads(p.decode(sys.stdout.encoding))
+
+
+def generate_media_thumb(video_path, out_path, skip_seconds=0):
+    ''' Uses ffmpeg to scrape out a thumbnail image from a video file. '''
+    ffmpeg = settings.WAGTAILMEDIA_FFMPEG_CMD
+    subprocess.check_output([ffmpeg, "-y", "-v", "quiet", "-accurate_seek", "-ss", str(skip_seconds), "-i", video_path,
+                             "-frames:v", "1", out_path])
+    return out_path
+
+
+def get_stream_by_type(data, typestr):
+    ''' Returns the appropriate mediainfo stream data. '''
+    for stream in data['streams']:
+        if stream['codec_type'] == typestr:
+            return stream
+    return None
+
+
+def get_video_stream_data(data):
+    ''' Returns the video mediainfo stream data. '''
+    return get_stream_by_type(data, 'video')
+
+
+def get_audio_stream_data(data):
+    ''' Returns the audio mediainfo stream data. '''
+    return get_stream_by_type(data, 'audio')