I am pretty new with processing audio file. '
I want to build a web app that can take audio file and turn the into visualization for user like this https://github.com/CrowdCurio/audio-annotator
Right now I want to research on visualize audio datas. Original data that was stored in S3 come in two form .ts and .flac. That's why I want to ask if there's any visualization tool which can directly use .ts or .flac audio file.
Because right now the solution I think of will be first convert them into .wav or .mp3, so most visualization tool can process them, but .wav file is really storage-wasting as far as I know.
So if you know any approach or tool to do this. Please let me know!
Audio visualization requires audio data. Your compressed audio isn't audible until decoded. Therefore, you must decode them to PCM before visualizing.
This doesn't require that you store the files as WAV, but you'll at least have to decode them on-the-fly.
Related
I am using moviepy to generate MP4 files from sets of shorter clips, each with their own audio. The problem is that the resulting MP4 often has a very high dynamic range from one clip to the next and I would like to apply audio compression to make it easier on the ears. In Google I can only find results about audio information compression, but not about audio compression from the audio engineering perspective.
I would like to know if there is some way of doing this with moviepy, or with some other library. I have no issue with invoking (non interactive) command line utilities either.
Thank you.
I have recorded a video on my phone, I don't get why it needs to be encoded at all. Doesn't the format persist? Maybe I missing the point of encoding here. After the recording is it not already in format that is viewable to users?
It's a valid question if you wanted to just upload the existing MP4 file that was encoded on your phone and just stream it as a single bitrate HLS or DASH packaged file.
Most users of our service prefer that the uploaded MP4 file is first encoded to multiple bitrates and resolutions to allow for Adaptive Bitrate Streaming.
If you are not familiar with what Adapative Streaming is or how it works, I recommend watching a few of these - https://www.youtube.com/results?search_query=Adaptive+bitrate+streaming+overview
Or read through this article
https://en.wikipedia.org/wiki/Adaptive_bitrate_streaming
We have two types of encoding presets to enable this. One called Adaptive Streaming, which will generate a fixed "ladder" of bitrates and qualities, and one called Content Aware Encoding, which will look at your video, analyze it, and generate the best set of tracks and bitrates for the content type.
https://learn.microsoft.com/en-us/azure/media-services/latest/content-aware-encoding
Thanks,
John D.
How to get file information like sampling rate, bit rate etc of .raw audio files using terminal in linux? Soxi works for .wav files but it isn't working for .raw.
If your life depended on discovering an answer you could make some assumption to tease apart the unknowns ... however there is no automated way since the missing header would give you the easy answers ...
The audio analysis tool called audacity allows you to open up a RAW file, make some guesses and play the track
http://www.audacityteam.org
In audacity goto File -> Import -> Raw Data...
Above settings are typical for audio ripped from a CD ... toy with trying stereo vs mono for starters.
Those picklist widgets give you wiggle room to discover the format of your PCM audio given that the source audio is something when properly rendered is recognizable ... would be harder if the actual audio was noise
However if you need a programmatic method then rolling your own solution to ask those same questions which appear in above window is possible ... is that what you need or will audacity work for you ? We can go down the road of writing code to play off the unknowns mentioned in #Frank Lauterwald's comment
To kick start discovering this information programmatically, if the binary raw audio is 16 bit then each audio sample (point on the audio curve) will consume two bytes of your PCM file. For mono audio then the following two bytes would be your next sample, however if its stereo then these two following bytes would be the sample from the other channel. If more than two channels then just repeat. Typical audio is little endian. Sampling rate is important when rendering the audio, not when programmatically parsing raw bytes. One approach would be to create an output file with a WAV header followed by your source PCM data. Populate the header with answers from your guesswork. This way you could listen to this output file to help confirm your guesses.
Here is a sample 500k mono PCM audio file signed 16 bit which can be imported into audacity or used as input to rolling your own identification code
The_Constructus_Corporation_Long_Street-ycexQvMy03k_excerpt_mono.pcm
I am trying to write a code in c/c++ (objective c) to parse the audio and video data from mp4 file.
I know that data in mp4 file contains under the mp4 atom but not sure how i can parse out the audio and video data separately.
Thanks in advance for any help.
Mp4 format is fairly complicated. I suggest you use a library. But if you can't use a library, or just wan to learn the format, Than you must parse about a dozen boxes or atoms under the root moov box. The information from there can be used to find frames within the mdat atom. The full specifications is numbered ISO/IEC 14496-12 You should be able to find a copy online.
I have a program that captures and stores H.264 encoded video as well as audio into a proprietary format file. I need to be able to export that video and audio to an mp4 file. I prefer C# but will use C++ if necessary. Any suggestions?
To produce MPEG-4 Part 14 .MP4 file you need a multiplexer. There is a choice of multiplexers out there:
FFmpeg (libavformat)
DirectShow filters (free and open source from GDCL, commercial)
Windows 7+ Media Foundation file sink
API and complexity might vary because some of multiplexers are expected to be a part of pipeline, they are not completely standalone classes. You might want to check respective samples (and license agreements, perhaps, too) to see what is best for you.
Take a look at libmp4v2. Fairly straightforward to use..
http://code.google.com/p/mp4v2/