我执行下面的命令并获得 Stream＃0：0：Subtitle：unknown_codec （codec unknown_codec）未找到输出流＃0：0 FFmpeg命令：
final String demoVideoPath = "/sdcard/b.mp4";
final String subTitlePath="/sdcard/srtf.srt";
String ffmpegCommand[] = { "ffmpeg", "-i", demoVideoPath, "-i", subTitlePath,
"-map","1", "-c", "copy","-strict", "experimental","-c:v","mpeg","-crf","23","-preset","veryfast",
"/sdcard/output.avi" };
logcat的
Shellout[srt @ 0xc03930] Estimating duration from bitrate, this may be inaccurate
ShelloutInput #1, srt, from '/sdcard/srtf.srt':
Shellout Duration: N/A, bitrate: N/A
Shellout Stream #1:0: Subtitle: srt
ShelloutPlease use -b:a or -b:v, -b is ambiguous
ShelloutOutput #0, avi, to '/sdcard/output.avi':
Shellout Metadata:
Shellout major_brand : isom
Shellout minor_version : 512
Shellout compatible_brands: isomiso2mp41
Shellout creation_time : 2013-12-20 11:33:07
Shellout encoder : Lavf51.12.1
Shellout Stream #0:0: Subtitle: unknown_codec
ShelloutStream mapping:
Shellout Stream #1:0 -> #0:0 (srt -> ?)
ShelloutEncoder (codec unknown_codec) not found for output stream #0:0
如何处理unknown_codec错误。