MP4 is the short name for a special video format called MPEG-4. The format can compress large video content into a relatively small document while keeping its quality.

　　They named it MP4 mainly because it was regarded as an update from MP3. MP3 only compresses audio documents.

　　After MP3 players became popular, some technology companies started thinking about making videos that fit into people's pockets. In fact; most PDAs and some hand-held mobile phones already have video function.

　　Since then, manufacturers worldwide have joined in the rush. Among them are big companies like Sony, Microsoft and Apple, although they don't call their products MP4 players.

　　Sony called its product with video function the PMP (Portable Media Player). Microsoft prefers PMC (Personal Media Centre), while some others call the gadgets PVPs (Personal Video Player).

　　But, basically, these products all have the same core function--playing video content.

　　An MP4 player is not just an MP3 player with an extra video function.

　　In fact, MP4 players must be able to play, record, and transform large video content. That requires an overall change in both hardware and software. Storage must be enlarged, display strengthened, speakers powered, software upgraded, and appearance redesigned.

　　Since video function enriched the players, other functions such as games, cameras can be added. Sony's PSP (Play Station Portable) was originally built for video games.

【2010届高三英语一轮复习必备精品同步练习：Module4 unit1】相关文章：

★ 2014届高考英语一轮复习课时作业(十八)必修3Module 6《Old and New》（外研版）

★ 重庆市2014高考英语阅读理解一轮（精品）训练题（19）附答案

★ 2014年牛津译林版高中英语总复习（第1轮）同步练习 M8《Unit 4 Films and film events》

★ 【北师大版】2014届高考英语一轮复习指导课时作业：Unit 8 A卷 Word版含解析

★ 【人教版】2014届高考英语一轮复习指导考点针对练：必修1 unit4《Earthquakes》

★ 2017年高考英语二轮复习精品资料：专题16 书面表达（教学案）（教师版）

★ 【北师大版】2014届高考英语一轮复习指导课时作业：Unit 5 A卷 Word版含解析

★ 湖南省汝城二中2014届高考英语一轮复习阅读训练 (14)

★ 【人教版】2014届高考英语一轮复习指导考点针对练：选修6 unit1《Art》

★ 【人教版】2014届高考英语一轮复习指导考点针对练：必修2 unit3《Computers》