FFmpeg音频不同步问题

Question

I've seen tons of threads about these but nothing seems to have changed for my problem.

Currently inside my Java program, I am calling the command line and using this command.

ProcessBuilder builder = new 
                 ProcessBuilder(
                         "cmd.exe", "/c", "ffmpeg -y -i " + "\"" + inputFile + "\" -vcodec libx264 -async 1 -f mp4 " + " -ss " + offset + " -c copy -t " + duration + " " + "\"" + outputFile + "\"");

Originally -vcodec, -async, and -f mp4 weren't there but in efforts to hopefully correct the audio, they have been placed there.

The audio is lagged by about ~1-2 seconds, I was wondering if anyone had any ideas? I've also tried to manually set the frame rate which still hasn't worked.

Here is another failed attempt.

ProcessBuilder builder = new 
                 ProcessBuilder(
                         "cmd.exe", "/c", "ffmpeg -y -i " + "\"" + inputFile + "\" -vcodec libx264 -async 1 -acodec libfaac -ab 128k -ac 2 -bt 5000k -b 5000k -r 59.940 -threads 0 -f mp4 " + " -ss " + offset + " -c copy -t " + duration + " " + "\"" + outputFile + "\"");

Input & Output files along with Offset and Duration are all fine, please don't question this.

Quick edit!

The input file will always have the extension .flv

Another EDIT When I remove the offset and duration arguments and use copyts instead, the entire file is converted to mp4 AND the audio is synced. The issue seems to lie in the offset and duration since I tried copyts before with the two but it still was desync'd.

Current

ProcessBuilder builder = new 
                 ProcessBuilder(
                         "cmd.exe", "/c", "ffmpeg -y -i " + "\"" + inputFile + "\"" + " -c copy -copyts " + "\"" + outputFile + "\"");

Answer 1

In your original command (the one at the top), replace -c copy with -c:a copy . You can get rid of the -async 1 .