Support calculating approximate duration about music-metadata HOT 5 CLOSED

That could very well be the reason.

On a good quality (using a recent Lame encoder) MP3 encoded file, it will do the duration calculation on the VBR/Xing/Info header. That header specifies the number of frames.

I just removed a silly rounding from that calculation. It is pretty accurate only thing what is missing is subtracting the "empty" space in the very last frame.

from music-metadata.

It should already work according your suggestion.

Taken from MpegParser.ts:421

if (this.frameCount === 3) {
        // the stream is CBR if the first 3 frame bitrates are the same
        if (this.areAllSame(this.bitrates)) {
          // subtract non audio stream data from duration calculation
          // The 128 bytes is based on a very unsafe assumtion that a ID3v1 will follow (ToDo: improve)
          const size = this.tokenizer.fileSize - (this.headerSize === 0 ? 128 : this.headerSize);
          this.format.duration = (size * 8) / header.bitrate;
          this.format.codecProfile = "CBR";
          return; // Done
        } else if (!this.readDuration) {
          return; // Done
        }
      }

I will ensure that clear test cases will demonstrate this, that does not seem to be the case.

from music-metadata.

Oh, I thought that approximation for CBR got removed because music-metadata took much more time to scan 4000+ mp3 files than its old version did; in fact, I couldn't see the scanning finish due to the "out-of-memory" error. Probably, this issue is related to #34. I'll check again after #34 resolved.

from music-metadata.

The test result with the latest release, 0.8.2 is very impressive!

To fully scan 4500+ files,

• music-metadata + mp3-duration for fallback takes only 7mins
• while musicmetadata + mp3-duration for fallback took 20mins.

I think I can get rid of mp3-duration from canary even if music-metadata still fails to calculate playtime for 6 files; I'll open this as a separate issue soon.

Thanks for the outstanding work!

from music-metadata.

@mycoboco, thanks for your reply and promising the benchmark.

Feel free to open an issue for the remaining 6 files or re-open this one.

from music-metadata.