Review of Video Search Engines
A review of search engines used to discover moving image (video) content.
Searching Online/JISC Digital Media/University of Bristol ©2013
This is one of a series of reviews which explore how digital media resources can be found on the web using search engines. Here we explore search engines used to discover moving image content (videos). JISC Digital Media also provides a Review of Image Search Engines and a Review of Audio Search Engines.
A video search engine is a web-based application that browses the web for video content. Some engines browse the entire web, while others are organised to search specific servers. In this review we explore a number of well known video search engines.
There is a huge and growing amount of video content on the web, which can make finding the video you’re looking for an extremely difficult task. This task is made significantly more difficult by the fact that video content is largely invisible to search engines.
Search engines employ complex algorithms (computer applications that process data) to find and rank search returns. Each search engine uses a different approach, and some only search within restricted databases, which is why each provides different returns based on the same search terms. For commercial reasons the exact nature of these algorithms are maintained as closely guarded secrets, however, it is generally accepted that while some search engines can look at how widely a video is used (i.e. linked to by others) to judge its relevance, and others employ speech recognition or Optical Character Recognition (OCR) technology to explore the verbal and textual content of video, most only evaluate the text-based content associated with video (e.g. the description, tags and other metadata), as well as user ratings. Because of this, search engines will rarely find videos that are hosted on web sites that have not been search engine optimised, that are not promoted using social networks, and have not been linked to by others (see: JISC Cetis blog - Ranking and SEO - light on a dark art).
Other important considerations are the rights associated with the content you find using search engines. While the search engine itself will have its own terms of service and will be protected by copyright, the individual items that it discovers will also be individually protected by copyright and intellectual property laws. Before using each item, please ensure that you understand its copyright status, as this will govern how and where you can use it. (see our advice: Copyright and Other Rights)
Comments made in this review are subjective and are provided as a guide only. You will need to use your own judgement when selecting which search engines to use and in evaluating any results that are returned.
Evaluation criteria and test search terms
To provide a ‘level playing field’ for our review we are using evaluation criteria which explore the search options, performance, presentation, and support available on each site, and a standard set of search terms (our evaluation criteria are listed at the end of this guide). Although this exercise is subjective, these criteria provide a standard basis for comparison. Readers familiar with our other search engine reviews should note that different search terms were used for this review.
This review was undertaken in May 2013. If you are reading this some time after that this date, you are advised to check the sites carefully and to ask the kinds of questions we have included in our evaluation criteria.
Our top 6 video search engines
Google Videos UK
Search results from Google Videos include videos discovered by Google search crawlers throughout the web, including YouTube, user uploads and other, non-Google hosting services.
Google ranks its search returns using commercially confidential, complex and changing algorithms. In addition to using keywords and other metadata associated with content, Google also explores in bound links to judge the importance and relevance of the content (its patented PageRank system).
The ‘Search Tools’ option allows you to narrow your search by location, duration, upload date, and quality. You can also limit your search to only those videos with closed captions, and by a short list of sources (e.g. bbc.co.uk or sussex.ac.uk). Google facilitates the use of ‘operators’ which can enable you to limit search by domain (See: Power Searching with Google online course) as well as search by phrase using quotation marks (e.g. “quantum physics”) and Boolean NOT (-) and OR (|) operators (e.g. -universe).
A ‘safe search’ drop down menu is located at the top right of the page. This facilitates filtering explicit search results and is turned off by default.
Search results are returned very quickly, with rarely less than a million returns for any of the search terms used in this review. The top results on all pages are related to search terms that have been paid for by advertisers, as have the non-video returns listed on the right side of the page.
Returns on the first page appeared to be highly relevant, but with so many returns it is possible that many are duplicates.
Google is well known for it’s plain, functional design. A thumbnail image, short description and upload date are provided for each video.
After your first search a ‘gear’ symbol appears in the top right of your browser window. Clicking this reveals a drop down menu which includes a 'Search Help' link. This gives access to a wide range of information about web searching using Google. Users can also access the Google Help Centre which offers further help and advice on a range of Google products.
YouTube only explores content that has been uploaded to its servers. However, as the preeminent user-generated video site on the web with, over 1 billion users and 75 hours of video uploaded every minute, YouTube has become the ‘go to’ site for finding video to support teaching, learning and research. YouTube is owned by Google and ranks search returns in a similar manner to Google in that it looks for relevance in the number and quality of backlinks to content, as well as ratings (‘likes’ vs ‘dislikes’), title, description, tags, annotations and subtitles.
The ‘filters’ option allows you to narrow your search by upload date, result type (e.g. video, channel, or playlist), and duration. An extremely useful feature is the facility to narrow your search by Creative Commons licence using the ‘Features’ filter (see: YouTube Creative Commons). The search defaults to sorting by relevance, but you can also search by rating and view count.
Like Google, YouTube facilitates search by phrase using quotation marks (e.g. “quantum physics”) and and Boolean NOT (-) and OR (|) operators (e.g. -universe) to narrow your search.
There is a ‘Safety Mode’ button located at the bottom of each page, which is turned off by default. YouTube state that enabling ‘Safety Mode’ avoids videos that may contain inappropriate content, but that “Safety Mode does not guarantee to block every such video”.
Search results are returned very quickly, with rarely less than a million returns for any of the search terms used in this review. The top results on all pages are related to search terms that have been paid for by advertisers.
Returns of the first page appeared highly relevant, but with so many returns it is possible that many are duplicates.
A clearly laid out, visual interface presents 23 returns per page illustrated with a thumbnail image, a short description, and information regarding age of upload, length of video and number of views for each video. Videos with closed captions are indicated by a ‘CC’ logo.
Many videos contain in-stream advertising which play before the selected content (and can be skipped after 5 seconds) or are shown as pop-up windows.
Users can select their preferred language, country of origin and can select safe search to restrict search returns to avoid inappropriate content.
‘Help’ is provided via a pop-up screen, located at the bottom of each page.
Bing is a search engine developed by Microsoft which crawls the web in a similar manner to other search engines but also gives preference to media RSS (mRSS) feeds that are optimised for inclusion in the Bing Video index (see: Bing Webmaster Blogs). Like Google, Bing has developed algorithms to sort results by order of relevance, however, in our tests search returns came from a limited number of sources (including Vevo, Daily Motion and WikiHow), with the vast the majority of video clips provided by YouTube.
Users can refine searches using Boolean logic (e.g. NOT and OR terms), and operators (e.g. site:ac.uk). Users can further narrow searches by ‘best match’ or date of upload, length, resolution and source.
Clicking the ‘gear’ symbol on the top right of the page reveals a ‘Preferences’ menu where users are presented with three ‘Safe Search’ explicit content filtering modes (‘Strict’, ‘Moderate’, and off).
Returns are provided very quickly but in significantly smaller numbers than Google (in this test, in the hundreds of thousands rather than millions). The returned results appeared to be relevant, but were primarily from one source (YouTube).
A clear, visual screen provides a thumbnail image for each item with limited information about the content of the videos presented - just title, date and source. However, a useful feature allows users to preview the full video (with audio) when the cursor is placed over the thumbnail image.
All results are presented on the page, which means that when a large number of returns are provided, reaching the bottom of the page (an the ‘help’ link) is not realistically possible.
Unlike Google, the site is free from overt advertising.
There is ‘Help’ link at the bottom of each page which links to useful advice (e.g. “keeping safe while watching videos”) and troubleshooting guides.
Yahoo search is currently powered by Microsoft. In our test, it provided many links to YouTube content in a similar manner to Bing, but also included more videos from other sources, including Daily Motion and WikiHow.
|Search Options||Very good||
Users are able to refine searches using Boolean logic, and operators (e.g. site:ac.uk). Users can further narrow searches by best match or date of upload, length, resolution and source.
Adult content is excluded with ‘safe search' as the default setting.
Advanced search is accessible via a ‘gear’ button on the top right of the page. This provides drop down menu which contains a link to advanced features, including the facility to exclude and include search terms, and narrow your search by video format (MPEG, Quicktime, Windows Media, Real and Flash), duration, and domain.
‘Safe search’ can be selected using a button located on the left side of the page. It is switched ‘on’ by default.
The search results were returned very quickly, but no indication is given of how many videos have been found.
The returned results appeared to be relevant, but were primarily from one source (YouTube).
A clear, visual screen with large thumbnails provides limited information about the content of the videos presented (36 per page) - just title and length. However, when the cursor is placed over the thumbnail image, a short description with source information is provided.
The site contains a small amount of advertising in the form of ‘click through’ links.
‘Help’ is accessed via a link at the bottom of each page. The information provided is generally useful, although finding specific advice on finding video content requires a further search.
Blinkx uses its proprietary speech recognition, video analytics and other media analysis software to search and rank video from over 35 million hours of indexed video provided by its 800 partners. The video content is accessed by Blinkx is supplied by a range of providers including BBC, FORAtv Science, HBO, MTV and Rolling Stone.
Blinkx offers a very limited search tool, comprised of a basic search with Boolean logic and phrase searching functionality (e.g. “particle physics” NOT award). Search returns appear to ranked in terms of relevance to the search term.
‘Safe search’ is on by default. Users are required to create a login account using either Facebook or Twitter in order to access ‘advanced’ features (e.g. to save favourite videos or see what friends are watching).
Blinkx responds quickly to search requests, but provides no information on how many videos have been found. Users are presented with a series of large thumbnail images for each video and are required to scroll down or use their browsers’ ‘zoom out’ function to view more than one return at a time.
The returns are presented as large thumbnails containing a short description, name and logo of provider, and age of upload. Users can also ‘favourite’ and ‘share’ videos using embedded icons.
The search engine is free of advertising but includes sponsored links to content.
The site provides a ‘Help’ link at the bottom of the page which offers non-searchable advice on the social aspects of the service and some troubleshooting tips.
AOL provides access to 'millions of free, high quality videos including music videos, news clips, movie trailers, viral videos, and full-length TV shows'. The videos are provided by AOL’s commercial ‘partners’ and tend to focus on news, lifestyle and ‘edutainment’ topics, segmented into 18 aggregated channels (including sports, life tips, video games and pets). At the time of writing AOL had no ‘education’ partners, but included a number of selected videos (‘Top Picks’) in their Education channel. Partners include BBC News (content not available in the UK), Howcast, and E!. The video search function is powered by Blinkx.
There are two search fields on each page - a general “Search” field and “Video search”. This may be confusing for new users.
AOL offers a very limited search tool, comprised of basic search with Boolean logic and phrase searching functionality (e.g. “particle physics” NOT franklin).
Returns can be listed by ‘relevancy’ and ‘recent’ postings only.
Users can also browse content by categories which include 'most viewed' and 'highest rated'. An explicit content filter is not available in video search, but can bet set by using the general web search interface and selecting the ‘Settings’ link in the top right of the page.
A ‘site map’ link at the bottom of each page provides an alphabetical list of the genres that users click and then can browse or search that particular category.
As with the other search engines, AOL responded quickly, but provided the lowest number of returns. Videos appear to be are ranked by ‘relevancy’ of the search term to the title. There were some ‘dead’ links within the first 20 returns.
The returns are presented as a list of thumbnails - 10 returns per page. Next to each the title, short description a link to the associated AOL Channel, date of upload and number of views.
The search screen is free of advertising but some videos automatically start playing ‘in stream’ advertising prior to the selected content. These inserts can run for up to 30 seconds and cannot be skipped.
There is clear advice and information about how viewers may use any content and about copyright issues. This can be found by clicking the 'terms of service' button at the bottom of the screen.
A ‘Help’ link can be found at the bottom of each page. There is no dedicated help for video searching and users must search for topics to find the information they require.
Video search engines for education
In addition to general video search engines, pedagogically useful search engines may help narrow your search further:
This serves education both as a free-to-Web discovery facility for nearly a million items of video and image content held in selected collections across the Web and also as an exceptional repository of more than 3,600 hours of archive digital video items not otherwise available elsewhere on the web. The discovered content, geared for use in research, learning and teaching, is available either as 'open content' or via login-in by those who study or work in education. Staff and students at subscribing institutions in UK Further and Higher Education can view and download footage via UK federation access from collections such as ITN News, Wellcome Library, Royal Mail Film Classics, Films of Scotland and St George's Hospital Medical School.
Kriticos is a customised Google search engine for visual media relevant to Engineering education, developed via a Jisc-funded project at the University of Liverpool. The site combines resource usage data provided by the Learning Registry and information shared by registered students at staff at the University regarding the usefulness of resources. This combination aims to provide search returns that are more relevant than standard Google searches.
While anyone can search the site, advanced features are only accessible to University of Liverpool staff and students. The ultimate aim is to open the site to other institutions and disciplines.
Talk Miner uses Optical Character Recognition (OCR) software to detect words on slides in indexed videos. More than 20,000 lecture videos from Stanford University, the University of California at Berkeley and TED have been indexed.
Please see below for links to further related JISC Digital Media resources:
In addition, further information about the availability of moving images for educational purposes can be found in the gateways and databases provided by the British Universities Film & Video Council (BUFVC).
In reviewing moving image search engines, we asked the following questions:
In the reviews that follow, we use the phrases "Poor", "Average", "Good" and "Very good" to provide an overall evaluation for each of the criteria listed above. These are based on a comparison of all the engines being reviewed and mean the following:
Among the best for this criteria.
Better than average, but not outstanding, for this criteria.
Mid-range for this criteria.
Below average for this criteria.
Test Search Terms
We tested the moving image search engines using the following terms:
|Category||Terms and Phrases||Rationale|
|General search terms||
General and unambiguous terms.
|Specific search terms||
Scientific name to test the indexing and an episode in history to test scope, relevancy using different expressions.
|Ambiguous search terms||
To test the weighting of the indexes.