I want to find out if I can get some data on the percentage wise distribution of video content, for different video codecs currently used for video encoding. I know there are different applications/use-case scenarios which have different encoder used but i want to consdier all that and have a overall usage number(%)
My guess is(highest to lowest % of content) -
H.264(AVC)
DivX
MPEG2
VP6
Where do H.263, MPEG4, VC-1, RV, Theora, etc. fit in here.
How may this look like in future?
PS:I would like this to be community wiki to have get wider range of inputs, if someone with privileges can do it for me please.
thank you.
-AD
I am guessing that WebM format (which is actually VP8) which is part of the WebM Project will see a rise since YouTube is encoding all of the videos in WebM format as an alternative.
I vote for WebM as a better quality and freer alternative to H.264
Related
I've authored some 4k videos and to my surprise it seems that Adobe Media Encoder won't let me export using various common formats at 4k resolutions.
For example mpeg2 won't go above HD 1920 resolution if you manually try to change the video size parameters. A little reading online seems to indicate this may be a technical limitation of the file format rather than anything specific with the AME software. I won't post links here as this was just talk on forums.
I then tried the same thing with AVI's and had the same issue of not being allowed to enter a resolution this high.
Is it really the case that formats such as mpeg2 and avi have some basic limitation that means they can't support resolutions as high as 4k ?
I've been using mp4 so far as an output format but just wondered if I should be aware of other formats that have this technical limitation and are not going to work.
The MPEG2 standard does not specify an encoding level for video at 4k resolution.
You can see a summary of what's available here:
https://en.wikipedia.org/wiki/H.262/MPEG-2_Part_2#Video_profiles_and_levels
I am developing an app and I am quite hesitant on allowing my users to share videos.
Mainly due the space that videos can take up in the server which adds a huge maintainance cost.
I have been reading around and I can see that there are lots of different libraries that allow me to compress video on iOS to make it easy to share.
After much researching I couldn't find any estimate on file size / second after compressed.)
I was wondering if anyone could share their experience with what file size / second I could expect with your preferred library in a video quality setting that is reasonable for mobile (I guess medium).
Based on the 2 following URL, you should be able to do what you want:
I suppose that you plan to use H264, and as the video is the major issue, First look at the following to choose the resolution & fps and the recommended bit-rate.
http://www.billhung.net/single_pages/video.encoding.resolution.vs.bitrate.by.experience.html#mozTocId728778
After follow the formula describe in:
Video bitrate and file size calculation
to compute the file size based on the maximum video duration you choose.
I am trying to record audio using an iPhone app and send the audio file through Mail. I need to compress the file before sending. what audio compression Algorithm to use in iPhone App?
It depends very much on your application.
Do you need loss-less compression, or can you afford losing some audio quality?
How fast to you need the file transfer to be?
How fast do you need the compression process to be?
Depending on the answers to these questions, you can choose one of the formats available in iOS.
You can read more here:
http://developer.apple.com/library/ios/#documentation/MusicAudio/Conceptual/CoreAudioOverview/Introduction/Introduction.html
http://developer.apple.com/library/ios/#documentation/MusicAudio/Conceptual/AudioQueueProgrammingGuide/AQRecord/RecordingAudio.html#//apple_ref/doc/uid/TP40005343-CH4-SW4
First choose the right bitrate. Typical bitrates for different purposes:
32kbit/s: AM Radio quality
48kbit/s: Common rate for long speech podcasts
64kbit/s: Common rate for normal-length speech podcasts
96kbit/s: FM Radio quality
128kbit/s: Most common bit rate for MP3 music
160kbit/s: Musicians or sensitive listeners prefer this to 128kbit/s
192kbit/s: Digital radio broadcasting quality
320kbit/s: Virtually indistinguishable from CDs
So if audio contains only speech 48 kbit/s is usually enough. For music 128 should be ok.
Second - you should use good compression codec. For detail information please check this link http://soundexpert.org/encoders-48-kbps but usually you should use AAC codec.
Other options (sample rate, bit depth, etc.) are not so important and usually you should leave them default.
I've got an app that enables end-users to upload their audio files. Mostly songs/music. Currently, I am using Zencoder for my encoding service, which allows .mp3, .m4a, .mp4 or .ogg
When a user uploads an audio file, it will be available for other users to listen too via the app as well. Would the mp3 format be suitable enough for this?
The licensing should be a major concern here. mp3 has some interesting licensing conditions based on whether your service is free to the end-user. Too complicated to go into length here, you can look it up on the web or contact Frauenhofer for more details.
The second obvious concern is bandwidth and audio quality. The sampling has to be high enough that the end-user cannot tell the audio has been limited or compressed, but the file still needs to be small enough that the file can be downloaded or streamed quickly. Any broadband connection these days can handle a 320kbps mp3 fairly easily.
Hopefully this will give you some good starting points for research:
wikipedia:Comparison_of_audio_formats
mp3 would suffice, mp4 would be better as it offers improved sound quality and compression over mp3. Ogg is a good format but has less broad support on players.
To state the obvious, the quality of the sound is very much dependent on the original file uploaded by the user. You will never improve on that quality, and each time you transcode between formats, you will degrade the quality.
If you ask people to compare between mp3, AAC (m4a, mp4) and ogg - they will give you different answers. Different codecs with different bit rates produce different audio print. Some claim that for certain specific music types you should prefer one format over another.
You can google different bit rates and comparisons easily - technical part is easy.
I would go for ogg. Here's why:
1) It's easily good enough for the job
2) It's an Open Source
3) You don't get into trouble (legally) using it together with upload encodings.
I'm putting together a site that will include some instructional videos that will be 1 to 3 minutes long. The users will be accessing these through standard and mobile browsers. I'm particularly concerned with users of i-devices, such as iPhone/iPod Touch/iPad.
To deliver the videos, I'm will probably use videojs.com player - it seems like a pretty robust choice. Unfortunately, I don't know first thing about what file formats and standards to use for encoding files. H.264 Baseline profile seems to be a good choice, but I really need some direction on where to read up on what might be the best choice.
Please help :)
The best resource I've found for this information is Dive Into HTML 5. They have a very concise breakdown of which formats will work with each of the browsers.
The long and short of it, however, is that h264 baseline is the way to go, especially if your HTML5 video player has Flash failover.
While HTML5 video is currently the standard in the mobile space, a back of the envelope calculation reveals that only about 40% of desktop browsers users can view it as compared to Flash's 99%+ market penetration. Moreover, you'd have to encode and store your videos twice (h264 and Theora) in order to reach all HTML5 video capable browsers.
However, by using h264 video and a Flash failover, you can cover all iDevices plus all browser that either don't support HTML5 video, or support HTML5 video for a format other than h264.
One word of warning: iDevices only support the h264 baseline up to level 3.0, so make sure to stay within these specs.
Hopefully that helps.