ffmpeg  -i 05-2.ogv -i text_box_trimmed.gif -filter_complex '[0:v][1:v]overlay[out]' -map '[out]'  -map '[0:a]' -acodec copy -vcodec libtheora -threads 0 -r 25 -g ^C -b:v 3000k res2.ogv

input #0, ogg, from '05-2.ogv':
  Duration: 00:01:45.01, start: 0.000000, bitrate: 1607 kb/s
    Stream #0:0: Video: theora, yuv420p, 640x480 [SAR 4:3 DAR 16:9], 25 fps, 25 tbr, 25 tbn, 25 tbc
    Metadata:
      ENCODER         : Lavf55.33.100
    Stream #0:1: Audio: vorbis, 44100 Hz, stereo, fltp, 64 kb/s
    Metadata:
      ENCODER         : Lavf55.33.100
Input #1, gif, from 'text_box_trimmed.gif':
  Duration: N/A, bitrate: N/A
    Stream #1:0: Video: gif, bgra, 189x44, 100 tbr, 100 tbn, 100 tbc
Output with label '0:a' does not exist in any defined filter graph, or was already used elsewhere.