#2740: Concatenating m4a files FAILED with output file name 'con.m4a' -------------------------------------+------------------------------------- Reporter: yumeyao | Type: defect Status: new | Priority: minor Component: | Version: undetermined | unspecified Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Summary of the bug: It seems the name 'con.m4a' is internally used or somewhat, I saw this message: {{{ Input #0, concat, from 'mylist.txt': Duration: 00:00:00.00, start: 0.000000, bitrate: 163 kb/s Stream #0:0: Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 162 kb/s File 'con.m4a' already exists. Overwrite ? [y/N] }}} Of course there's no such file there. If I choose Yes: {{{ [ipod @ 0261d2c0] muxer does not support non seekable output Output #0, ipod, to 'con.m4a': Metadata: encoder : Lavf55.10.100 Stream #0:0: Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, 162 kb/s Stream mapping: Stream #0:0 -> #0:0 (copy) Could not write header for output file #0 (incorrect codec parameters ?): Error number -1 occurred }}} And yes, just by changing the output file name, the whole process goes to work. How to reproduce: {{{ % ffmpeg -f concat -i mylist.txt -c copy con.m4a ffmpeg version N-54277-gff130d7 Copyright (c) 2000-2013 the FFmpeg developers built on Jun 30 2013 01:20:12 with gcc 4.7.3 (GCC) }}} (This is the version from http://ffmpeg.zeranoe.com/builds/, I was just lazy to build it myself because I just wanted to try out the concat function instructed in the wiki: [http://ffmpeg.org/trac/ffmpeg/wiki/How%20to%20concatenate%20(join,%20merge)%...] mylist.txt content: {{{ 1.m4a 2.m4a }}} -- Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2740> FFmpeg <http://ffmpeg.org> FFmpeg issue tracker