bytedeco/javacv

Problem of FFmpegFrameRecorder when using javaCV to call ffmpeg for audio codec and output audio

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#1,617 opened on Apr 2, 2021

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Description

Hello, I have a problem when using javaCV to call ffmpeg for audio transcoding. I don't know if it is a bug.

I built a FFmpegFrameGrabber and set the output parameters for it.

  • When I use stream output Using the following constructor
public FFmpegFrameRecorder(OutputStream outputStream, int audioChannels) {
        this(outputStream.toString(), audioChannels);
        this.outputStream = outputStream;
        this.closeOutputStream = true;
    }

, the final audio file will lack a ‘xing’ header data.

  • When I use filename to specify his output audio path, Call the following constructor
public FFmpegFrameRecorder(String filename, int audioChannels) {
        this(filename, 0, 0, audioChannels);
    }

the generated audio file has no problem, including the "xing" header information. The two files differ by 180 bytes.

Hope to get answers and help from everyone, thanks!

Contributor guide

Research direction
Investigate why the FFmpegFrameRecorder constructor that takes an OutputStream results in a missing xing header, comparing it with the filename constructor. Check if the outputStream handling or the toString() call causes differences in the muxer initialization.
Tech stack
java
Domain
backend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
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Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
Java
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
55