Concat two mp4 files with ffmpeg without losing quality

I want to concatenate 2 videos using ffmpeg. I am using:

ffmpeg -i output1.mp4 -scodec copy -vbsf h264_mp4toannexb i0.ts

But the mp4 file I get looks much worse then the source file.

Here is the information about both the files

   Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'output1.mp4':
   Metadata:
   major_brand     : isom
   minor_version   : 1
   compatible_brands: isom
   creation_time   : 2013-06-13 15:40:36
   Duration: 00:00:15.72, start: 0.000000, bitrate: 2053 kb/s
   Stream #0.0(und): Video: h264 (High), yuv420p, 1280x720, 1931 kb/s, 25 fps, 25 tbr,   12800 tbn, 50 tbc
   Stream #0.1(und): Audio: aac, 44100 Hz, stereo, s16, 128 kb/s

  Input #0, mpegts, from 'i0.ts':
  Duration: 00:00:15.64, start: 1.400000, bitrate: 1382 kb/s
  Program 1 
  Metadata:
  service_name    : Service01
  service_provider: Libav
  Stream #0.0[0x100]: Video: mpeg2video (Main), yuv420p, 1280x720 [PAR 1:1 DAR 16:9], 104857 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
  Stream #0.1[0x101](und): Audio: mp2, 44100 Hz, stereo, s16, 128 kb/s

How can I solve this problem?