Questions tagged [pcm]

PCM (Pulse-code modulation) is a method used to represent digital samples of the analog signals.

Filter by
Sorted by
Tagged with
1
vote
1answer
30 views

Extracting audio, don't understand PCM options

I've got the audio bitdepth, frequency and channels down. Pretty simple to understand, but cannot find enough information on the different PCM formats. I do understand the numbers correlate to the ...
0
votes
0answers
33 views

ffmpeg - How to prevent innacurate duration when converting from pcm to wav?

I have the following command: ffmpeg -f f32le -ar 44100 -channels 2 -i input.pcm -y -acodec pcm_s16le -f wav output.wav input.pcm is the pcm data that comes from a 2 seconds wav file. However, when ...
1
vote
1answer
154 views

How to encode into WAV ADPCM?

How to encode WAV PCM into WAV with ADPCM encoding? I tried FFmpeg. I can see from the old FFmpeg codec list, that it previously supported encoding into adpcm_adx, adpcm_ima_qt, adpcm_ima_wav, ...
0
votes
1answer
216 views

How to convert raw PCM data to a valid WAV file with ffmpeg?

I run this command: ffmpeg -f f32le -i pipe:0 -f wav pipe:1 ffmpeg version 4.1-tessus https://evermeet.cx/ffmpeg/ Copyright (c) 2000-2018 the FFmpeg developers built with Apple LLVM version 10.0.0 (...
0
votes
0answers
48 views

ffmpeg shortening wav file when converting from pcm

I am using this command to convert large pcms (90 mins recording) into wav files: ffmpeg -f s16be -ar 11025 -ac 2 -acodec pcm_s16be -i f7.pcm f7.wav The wav I get back is usually about 50 - 65 ...
1
vote
0answers
186 views

Using a ALSA PCM as an input device for Chromium?

I have a Matrix Creator which I want to use as an input for a speech to text platform, running through Chromium (using webkitSpeechRecognition). My problem is that I do not have it available as a ...
2
votes
1answer
3k views

FFmpeg raw audio and H264 in RTSP

Trying to grab correctly video and audio data from an IP camera Hikvision. Everything works like a charm when doing so for H264 + MP2 for example. When trying to grab RAW audio in PCM s16le - smile ...
1
vote
1answer
799 views

How accurate and reliable is loudness analysis (ebur128) in ffmpeg for PCM?

I need to test a lot of files on possible audio normalization issues, files can be of various containers and audio encoding formats but mostly PCM audio. I tried Rhozet QC solution but found it ...
-1
votes
1answer
656 views

Is WAV (PCM) format bit rate is really CBR?

You know, all modern audio codecs bit rate modes are VBR, even if you restrict the settings to for example: MP3 128 CBR, the encoded result is between 120 to 135 ( a bit different with different ...
0
votes
1answer
841 views

How to extract Blu-ray audio without any conversion?

As avconv (forked from ffmpeg) said, the format of Blu-ray audio stream is called pcm_bluray, but why most of the tutorials say using -acodec pcm_s**le flag (** depends on its sample rate)? Are they ...
7
votes
2answers
2k views

Why Is Conversion From An MP3 To WAV (PCM) Lossless?

I understand that when converting between audio formats where no stream encoding is involved like when converting between WAV (PCM), AIFF, FLAC, ALAC, WMA Lossless, and etc, the process is usually ...
0
votes
0answers
53 views

Many microphones in windows

I need to record from as many as 40 microphones simultaneously on a single Windows 7 PC. These microphones will be present as USB audio adapters connected to powered USB hubs (so limited power isn't ...
0
votes
1answer
251 views

ffmpeg option, subchunk1size = 16

I have a wav file. How can I use ffmpeg with specific options to convert it to a wave file with subchunk1size = 16.
2
votes
1answer
193 views

How to stream desktop through audio jack (3.5) using dsp

Is it possible to stream my desktop over audio system? I mean some kind of cat /dev/fb0 > /dev/dsp? Or to pulse-code my desktop using built-in soundcard and to stream it over optical spdif audio-...
2
votes
2answers
9k views

How to convert PCM to MP3?

I have some .pcm files and I want to convert them to high quality .mp3 format. How can I do that? I've tried searching online but haven't found any programs that can do this. Ay suggestions? ...
1
vote
2answers
316 views

HDMI video stream

I am trying to determine the format of the audio portion of a video being sent from a digital device (DVD player, DVR, etc.) to a digital TV via an HDMI cable. My understanding is that the audio ...
1
vote
0answers
296 views

PCM Audio file and volume

I'm working with raw pcm files(with no headers) and I was wondering, does anyone know the calculation to find the current volume of a section of sound? I have all the information on the file, such as ...
1
vote
2answers
1k views

The audio of an FFmpeg converted mov file works in VLC but fails in Adobe Premiere cs5

I use this line to convert the mov file (Mark II 5D footage) to 720p: ffmpeg -i source.mov -s 1280x728 -vf crop=1280:720:0:0 -sameq -acodec copy dest_file.mov When I drag the result file to premiere,...
0
votes
1answer
218 views

PCM sound level resets in Ubuntu 8.04

I am using Ubuntu 8.04 and seeing that PCM volume above 75% results in very poor sound quality. So, I brought it down. But the problem is, after every reboot it resets to 100%. How can I save the PCM ...
3
votes
2answers
6k views

Converting WAV to PCM

I have WAV files and need to convert them to PCM (44,1k, 16bit, Mono) format. How can I do this from the DOS console?
4
votes
3answers
7k views

How to play a PCM file on an UNIX system?

I'm trying to figure out how to use libmad with C. The trouble is, libmad converts audio files to .pcm files and I'm unable to find a way to play these files. There is no straightforward .pcm player, ...