This gives you quality than most pre-made samples.
Even when you find an H.263 sample, issues are common. Here is a troubleshooting table. h 263 video sample download better
<table border="1"> <tr> <th>Filename</th> <th>Resolution</th> <th>Bitrate</th> <th>Source</th> </tr> <tr> <td><a href="https://media.xiph.org/derf/foreman_cif_h263.avi">foreman_cif_h263.avi</a></td> <td>352x288</td> <td>~384 kbps</td> <td>Xiph Derf</td> </tr> <tr> <td><a href="https://media.xiph.org/derf/mother_daughter_cif.y4m">mother_daughter_cif.y4m</a> (Convert to H.263)</td> <td>352x288</td> <td>Raw</td> <td>Reference</td> </tr> <tr> <td><a href="ftp://vqeg.its.bldrdoc.gov/HDTV/samples/h263/">VQEG_H263_64k.3gp</a></td> <td>176x144</td> <td>64 kbps</td> <td>VQEG Standard</td> </tr> </table> This gives you quality than most pre-made samples