[FFmpeg-user] Joining mp4 files with out Audio re-encoding

[Murthy avsn]

Hi all,
I am joining two mp4s using the following process,
1.ffmpeg -i video1.mp4 -codec copy -bsf  h264_mp4toannexb  video1.ts2.ffmpeg -i video2.mp4 -codec copy -bsf  h264_mp4toannexb  video2.ts3.ffmpeg -i concat:video1.ts|video2.ts -c:v copy join.mp4
Every thing is Ok with this process.
Problem is when i use -c:a copy I am getting some errorsHere are those errors
Input #0, mpegts, from 'concat:f1.ts|f2.ts':  Duration: 00:05:16.89, start: 1.400000, bitrate: 770 kb/s  Program 1     Metadata:      service_name    : Service01      service_provider: FFmpeg    Stream #0:0[0x100]: Video: h264 (Constrained Baseline) ([27][0][0][0] / 0x001B), yuv420p, 640x360, 24 fps, 24 tbr, 90k tbn, 48 tbc    Stream #0:1[0x101](und): Audio: aac ([15][0][0][0] / 0x000F), 44100 Hz, stereo, s16, 102 kb/sFile 'out.mp4' already exists. Overwrite ? [y/N] yOutput #0, mp4, to 'out.mp4':  Metadata:    encoder         : Lavf54.6.101    Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 640x360, q=2-31, 24 fps, 90k tbn, 90k tbc    Stream #0:1(und): Audio: aac ([64][0][0][0] / 0x0040), 44100 Hz, stereo, 102 kb/sStream mapping:  Stream #0:0 -> #0:0 (copy)  Stream #0:1 -> #0:1 (copy)Press [q] to stop, [?] for help[mp4 @ 0x9cf7100] malformated aac bitstream, use -absf aac_adtstoascav_interleaved_write_frame(): Operation not permitted
I want to avoid audio re-encoding so that joining will be more faster.Can some one please suggest any alternative to avoid audio re-encoding.

Thank you all.