I have a few audio files without file extension tag. it can be detected with the following info:
File Type: RIFF (little-endian) data, WAVE audio, mono 16000 Hz
MIME Type: audio/x-wav
I wonder how I can convert them to regular wave files.
audio/x-wav is the MIME Type. A MIME Type is just an identifier for file formats transmitted on the Internet. Most probably the audio is a PCM uncompressed audio and it is already in a wave container (*.wav)
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I want to convert the asf file which is having codec "A4;ACELP;;Racal Recorders".
Codec is detected using MediaInfo library. The file is not playable using any common audio/video players like VLC. Converting to wav using FFmpeg fails with error unknown codec.
Is there any converter/FFmpeg-plugin available for this codec?
PS:I'm not able to share the file due to security policy
I need to convert an audio file (any common format) into a rtp stream saved in a .pcap file with G.722 Codec.
The generated .pcap file will be sent with SIPp using:
<exec play_pcap_audio="g722.pcap"/>
I know it is possible to send also .wav file with the following command, if the .wav is correctly encoded:
<exec rtp_stream="g711.wav"/>
But seems that is not possible to encode a .wav with G722.
There are multiple solutions on the web and SO on how to convert a .pcap into an audio file, but I'm actually looking for the opposite.
Steps to convert wav audio to .pcap file:
Split audio to 20 ms chunks
Encode each chunk with G.722 encoder
Create RTP header for each encoded chunk
Save RTP stream to .pcap
I've never used SIPp, but if it can process encoded G.722 stream, then use ffmpeg for encoding:
ffmpeg -i sample.wav -ar 16000 -acodec g722 sample.g722
Get softphone supporting wav files as source and G.722 codec, make call with only G.722 enabled, capture RTP stream to pcap.
Is there any difference between M4A audio files and AAC audio files or are they exactly
the same thing but with a different file extension?
.M4A files typically contain audio only and are formatted as MPEG-4 Part 14 files (.MP4 container).
.AAC is not a container format and instead it is a raw MPEG-4 Part 3 bitstream with audio stream encoded.
Note that M4A does not have to contain exactly AAC audio, there are other valid options as well.
There are raw video and audio streams, this streams cannot be played directly on most video/audio player, they need to be "encapsulated" on a transport, a raw H.264 video stream and a raw AAC audio stream need to be inside a MP4 encapsulator, it can be also inside an AVI or MOV encapsulator.
A MP4 file can contain a H.264 video stream and/or an AAC audio stream, but for some reason someone decided that a MP4 file that contains video and audio use the file extension M4V (v for video) and if it is an MP4 file that only contains audio to use the M4A extension, that is a common practice in other encapsulators like Windows Media which use WMV and WMA, or OGG which use OGV and OGA, silly as it seems.
So a file that has a M4A file extension is an MP4 file that can contain a AAC audio track but it is not always the case, that's why programs like mediainfo become handy to know what is inside a file.
They are not the same thing.
An .m4a file is basically the same thing as an mp4; it is only a container format. codec != container It does not imply a codec, and therefore it can only contain mp3, ac3 or any other audio codec.
An .aac file contains concatenated AAC frames pre-pended with ADTS headers (and optionally an ID3 tag).
Currently, I am developing a ucma 3.0 vxml application. In the voicexml document , I use a record element to take the caller's recording, and then send the recording to an exteranl web server and save it to a wav file.
whats the format of the saved wav file, 8KHz/8-bit or 8KHz/16-bit or 16KHz/16-bit?
Can I set or change the audio format of the ucma vxml Browser to generate audio with different format?
They supported audio formats for UCMA VoiceXML are:
Raw (headerless) 8kHz 8-bit mono mu-law [PCM] single channel. (G.711) -- audio/basic (from [RFC1521])
Raw (headerless) 8kHz 8 bit mono A-law [PCM] single channel. (G.711) -- audio/x-alaw-basic
WAV (RIFF header) 8kHz 8-bit mono mu-law [PCM] single channel. -- audio/x-wav
WAV (RIFF header) 8kHz 8-bit mono A-law [PCM] single channel. -- audio/x-wav
The part after the "--" is the mime type. You specify the mime type in the "type" attribute of the "record" element.
I need to find the codec of an audio file. How can I do this?
Do I need to write code to do this or is there a simpler way?
Please help me. If possible share helpful links.
The good old file utility will reveal lots of information about audio files, sometimes including the codec:
$ file X.wav
X.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, mono 16000 Hz
#bhebsquines
"It is important to distinguish between a file format and an audio codec. A codec performs the encoding and decoding of the raw audio data while the data itself is stored in a file with a specific audio file format. Although most audio file formats support only one type of audio data (created with an audio coder), a multimedia container format (as Matroska or AVI) may support multiple types of audio and video data." - http://en.wikipedia.org/wiki/Audio_file_format
The application gspot does a good job of pulling codecs from audio and video files.
http://www.headbands.com/gspot/
run it and drag a file into the window. It will pull all of the data from there. Note that some audio files will not display a codec as they are made from "Raw" audio.
You can identify your codec by extenion name itself example file1audio.mp3 or fileaudio.avi, .mp3, .avi will be your file type or codec, you can use k-lite codec pack for your different type audio format. use this link http://www.free-codecs.com/download/k_lite_codec_pack.htm