error when converting mts to mp4 - ffmpeg

Question

I have many video files that I want to convert to mp4.
so I installed ffmpeg on my win7 PC (64 bit) which is using shared library.
I tried to convert an MTS file to MP4 and I get this error.
What is the problem?
$ ffmpeg -i 20140806114251.MTS 20140806114251.mp4
ffmpeg version N-68788-g37b35fe Copyright (c) 2000-2014 the FFmpeg developers
built on Dec 30 2014 22:18:55 with gcc 4.9.2 (GCC)
configuration: --disable-static --enable-shared --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-lzma --enable-decklink --enable-zlib
libavutil 54. 15.100 / 54. 15.100
libavcodec 56. 19.100 / 56. 19.100
libavformat 56. 16.102 / 56. 16.102
libavdevice 56. 3.100 / 56. 3.100
libavfilter 5. 6.100 / 5. 6.100
libswscale 3. 1.101 / 3. 1.101
libswresample 1. 1.100 / 1. 1.100
libpostproc 53. 3.100 / 53. 3.100
Input #0, mpegts, from '20140806114251.MTS':
Duration: 00:00:19.04, start: 1.033367, bitrate: 16273 kb/s
Program 1
Stream #0:0[0x1011]: Video: h264 (High) (HDMV / 0x564D4448), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
Stream #0:1[0x1100]: Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), fltp, 448 kb/s
Stream #0:2[0x1200]: Subtitle: hdmv_pgs_subtitle ([144][0][0][0] / 0x0090), 1920x1080
[libx264 # 0000000002b60a20] using SAR=1/1
[libx264 # 0000000002b60a20] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 # 0000000002b60a20] profile High, level 4.0
[libx264 # 0000000002b60a20] 264 - core 144 r2525 40bb568 - H.264/MPEG-4 AVC codec - Copyleft 2003-2014 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
[libvo_aacenc # 00000000028a4020] Unable to set encoding parameters
Output #0, mp4, to '20140806114251.mp4':
Stream #0:0: Video: h264 (libx264), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=-1--1, 29.97 fps, 29.97 tbn, 29.97 tbc
Metadata:
encoder : Lavc56.19.100 libx264
Stream #0:1: Audio: aac, 0 channels, 128 kb/s
Metadata:
encoder : Lavc56.19.100 libvo_aacenc
Stream mapping:
Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
Stream #0:1 -> #0:1 (ac3 (native) -> aac (libvo_aacenc))
Error while opening encoder for output stream #0:1 - maybe incorrect parameters such as bit_rate, rate, width or height
EDIT : I thought I solved this problem by using
ffmpeg -i filename1.mts filename1.mkv
my Samsung LED TV supports mkv file and during the conversion, it shows
Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
Stream #0:1 -> #0:1 (ac3 (native) -> vorbis (libvorbis))
But Alas! my TV doesn't support vorbis codec. It only supports mp3, ac3, lpcm, and ADPCM when using mkv container. So the question is : How do people select output audio codec?

Answer 1

I solved this by using
ffmpeg -i file1.mts -y -acodec ac3_fixed file1.mkv
see my EDIT above.
and if you want to change the file format (keeping the codec type),
ffmpeg -i file1.MTS -c copy file1.avi
This doesn't take any time and finishes instantly.
EDIT : the file generated using -c copy cannot be played on my Samsung LED TV. The first method works though slow in conversion.

Answer 2

Selecting an audio encoder
So the question is: How do people select output audio codec?
Choose an audio encoder with -c:a such as -c:a libmp3lame for MP3 audio.
See ffmpeg -encoders for a list of encoders supported by your ffmpeg build.
Stream copy
You may be able to simply re-mux (stream copy) to a new container format, and avoid re-encoding, and your TV may play it:
ffmpeg -i input.mts -c copy output.mkv