FFMPEG: Converting from raw audio to audio/mp4 (audio is being converted with slow speed)

Asked Dec 28 '17 at 19:56

Active Dec 29 '17 at 14:39

Viewed 865 times

If I convert from mp3 to mp4 directly everything works perfectly. But if I try to convert from raw pcm, the audio speed is slowed down.

I've tried the following (this works):

ffmpeg -i mp3/1.mp3 -strict -2 final.mp4

This doesn't work as expected:

ffmpeg -f s16le -i final.raw -strict -2 -r 26 final.mp4

With the following output:

Input #0, s16le, from 'final.raw':
  Duration: 00:08:37.38, bitrate: 705 kb/s
    Stream #0:0: Audio: pcm_s16le, 44100 Hz, 1 channels, s16, 705 kb/s
File 'final.mp4' already exists. Overwrite ? [y/N] y
Output #0, mp4, to 'final.mp4':
  Metadata:
    encoder         : Lavf56.40.101
    Stream #0:0: Audio: aac ([64][0][0][0] / 0x0040), 44100 Hz, mono, fltp, 128 kb/s
    Metadata:
      encoder         : Lavc56.60.100 aac
Stream mapping:
  Stream #0:0 -> #0:0 (pcm_s16le (native) -> aac (native))
Press [q] to stop, [?] for help
size=    8273kB time=00:08:37.38 bitrate= 131.0kbits/s
video:0kB audio:8185kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.073808%

I've tried to set parameters like:

ffmpeg -ar 44100 -f s16le -i final.raw -strict -2 -r 26 final.mp4

With no luck.

In order to get the PCM from mp3 I'm using nodejs lame decoder:

var decoder = new lame.Decoder({
        channels: 2,
        bitDepth: 16,
        sampleRate: 44100,
        bitRate: 128,
        outSampleRate: 44100, // 22050
        mode: lame.STEREO
    });

edited Dec 29 '17 at 14:39

asked Dec 28 '17 at 19:56

Valdir

Show the console output from the commands that do not work as expected. – llogan Dec 28 '17 at 20:15
And share some details about the raw files. How are they created? – Gyan Dec 28 '17 at 20:17
You have the wrong sample rate. – Brad Dec 29 '17 at 03:54
@Mulvya Updated – Valdir Dec 29 '17 at 14:39
@LordNeckbeard updated – Valdir Dec 29 '17 at 14:39
@Brad I've updated it with some details – Valdir Dec 29 '17 at 14:40
1

`44100, // 22050` --> is it 44100 or 22050? – Gyan Dec 29 '17 at 14:47
@Mulvya I've tried both without success – Valdir Dec 29 '17 at 14:59
Try `ffmpeg -ar 44100 -ac 2 -f s16le -i final.raw -strict -2 final.mp4`. Try with `-ar 22050` as well. One detail missing is whether LAME outputs planar or interleaved. – Gyan Dec 29 '17 at 15:14
@Mulvya No luck, I've tried converting to raw using ffmpeg also `ffmpeg -i mp3/1.mp3 -f s16le -acodec pcm_s16le -ar 44100 final.raw` Same result – Valdir Dec 29 '17 at 15:44
Can you provide a small sample input file? – llogan Dec 30 '17 at 21:08

FFMPEG: Converting from raw audio to audio/mp4 (audio is being converted with slow speed)

0 Answers0