In ipod/mov/mp4 muxer, always write esds descriptor length using 4 bytes,

[ffmpeg] / tests / ref / vsynth2 / mpeg4

8ffbe8ce43fe126b12cf9621717d641b *./tests/data/vsynth2/odivx.mp4
119809 ./tests/data/vsynth2/odivx.mp4
90a3577850239083a9042bef33c50e85 *./tests/data/mpeg4.vsynth2.out.yuv
stddev:    5.34 PSNR: 33.57 MAXDIFF:   83 bytes:  7603200/  7603200