Raw audio - Revision history

Andre Castro: /* convert an mp3 to raw */

2018-01-29T13:26:58Z

convert an mp3 to raw

← Older revision		Revision as of 15:26, 29 January 2018
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	Find out the properties of the audio file with ffmpeg		Find out the properties of the audio file with ffmpeg
	ffmpeg -i file.mp3		ffmpeg -i file.mp3
			sox -V file.wav

	Sox has no handler for mp3 formate, hence you have need to convert from mp3 to wav, ffmpeg does it quickly and well		Sox has no handler for mp3 formate, hence you have need to convert from mp3 to wav, ffmpeg does it quickly and well
Line 17:		Line 18:

	Sox: display information on the wav file		Sox: display information on the wav file
	sox -V file.~~wac~~		sox -V file.wav

	Sox: convert the wav file to raw		Sox: convert the wav file to raw
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	** 32bit: S32_LE S32_BE U32_LE U32_BE		** 32bit: S32_LE S32_BE U32_LE U32_BE
	*<code>-c</code>: channel number		*<code>-c</code>: channel number
	*<code>-r</code>: sample rate. 4000 Hz is the minimum allowed by aplay. 44100Hz is the default sample rate for CDs		*<code>-r</code>: sample rate. 4000 Hz is the minimum allowed by aplay. 44100Hz is the default sample rate for CDs



	== convert image to raw audio==		== convert image to raw audio==

2018-01-28T22:27:41Z

@@ Line 1: / Line 1: @@
 RAW Audio is an audio file format for storing uncompressed audio in raw form. Comparable to WAV or AIFF in size, RAW Audio file does not include any header information (sampling rate, bit depth, endian, or number of channels)
-<code>-f</code> sample format / bit rate:
+Find out the properties of the audio file with ffmpeg
-* 8bit: S8 U8
+ ffmpeg -i file.mp3
-<code>-c</code>: channel number
+Sox has no handler for mp3 formate, hence you have need to convert from mp3 to wav, ffmpeg does it quickly and well
-<code>-r</code>: sample rate. 4000 Hz is the minimum allowed by aplay. 44100Hz is the default sample rate for CDs
+* <code>-acodec pcm_s16le</code>: audio codec is PCM signed 16bit
-If we want to '''write the result of playing the raw file into an audio file with a head''', like a wav we can use [http://sox.sourceforge.net/ Sox] for the job
+play (sox): play back the raw file at same bit-rate and sample-rate
-Notice that I have to indicate the same audio parameters:
+Same thing but with aplay:
-<code>-e signed-integer</code> encoding
+== convert image to raw audio==
@@ Line 33: / Line 67: @@
 =Links=
 * [https://web.archive.org/web/20160525083851/http://www.fmtz.com:80/misc/raw-audio-file-formats Raw Audio File Formats Information] (at the [[Wayback Machine]])

2018-01-22T15:18:08Z

← Older revision		Revision as of 17:18, 22 January 2018
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	~~#REDIRECT~~ [[~~Generating~~ audio ~~with python~~]]		RAW Audio is an audio file format for storing uncompressed audio in raw form. Comparable to WAV or AIFF in size, RAW Audio file does not include any header information (sampling rate, bit depth, endian, or number of channels)


			cat img.png > audio.raw
			aplay -f S8 -c 1 -r 4000 audio.raw

			<code>-f</code> sample format / bit rate:
			* 8bit: S8 U8
			* 16bit: S16_LE S16_BE U16_LE U16_BE
			* 24bit: S24_LE S24_BE U24_LE U24_BE
			* 32bit: S32_LE S32_BE U32_LE U32_BE

			<code>-c</code>: channel number

			<code>-r</code>: sample rate. 4000 Hz is the minimum allowed by aplay. 44100Hz is the default sample rate for CDs



			If we want to '''write the result of playing the raw file into an audio file with a head''', like a wav we can use [http://sox.sourceforge.net/ Sox] for the job

			sox -r 4000 -b 8 -c 1 -e signed-integer pg_0018.raw pg_0018.wav

			Notice that I have to indicate the same audio parameters:

			<code>-r 4000</code> sample sate

			<code>-b 8</code> bit rate

			<code>-e signed-integer</code> encoding



			=Links=
			* [https://web.archive.org/web/20160525083851/http://www.fmtz.com:80/misc/raw-audio-file-formats Raw Audio File Formats Information] (at the [[Wayback Machine]])

2013-10-08T14:37:52Z

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#REDIRECT [[Generating audio with python]]