Sec. 4. If a defendant is convicted of a felony, is eligible for release on bail pending appeal under Article 44.04(b), and gives notice of appeal, he shall be transferred to the Texas Department of Criminal Justice on a commitment pending a mandate from the Court of Appeals or the Court of Criminal Appeals upon request in open court or upon written request to the sentencing court. Upon a valid transfer to the department under this section, the defendant may not thereafter be released on bail pending his appeal.