Cantonese Pinyin 廣東話拼音

I bought a Cantonese textbook recently. It was really a nice book which provide detailed explanation about Cantonese dialogue and vocabulary. However, I found the Cantonese Pinyin that labelled on the book was different from the HongKong one which I knew before. Does Cantonese have different Pinyin system and which one should I focus on?
我最近買左一本粵語教科書。我覺得呢本書真系好好，對話同埋詞語噶解釋都好道地地道。但系我都發現呢本書噶粵語拼音同我之前睇到噶香港拼音好唔同。粵語系唔系有唔同噶拼音系統？學邊種會好d？

Example in the text book:
書中例子:
Heng1 gong2 seng1 ban6 din6 xi6 toi4 sou3 mug6 hou2 xiu2,
香港商辦電視台數目好少，
min5 fei5 din6 xi6 toi4 yed1 jid6 ji2 yeo5 leng5 gan1,
免費電視台一直有兩間，
yeo5 gei2 gan1 hei6 yeo5 xin3 guong2 bo3 ge3, dou1 yiu3 seo1 fei3.
有幾間系有線廣播噶，都要收費。

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其實我看不懂上面的拼音，香港學生一般用以下的拼音法：

hoeng1 gong2 soeng1 baan6 din6 si6 toi4 sou3 muk6 hou2 siu2

香港商辦電視台數目好少

min5 fai3 din6 si6 toi4 jat1 zik6 jau5 loeng5 gaan1

免費電視台一直有兩間

jau5 gei2 gaan1 hai6 jau5 sin3 gwong2 bo3 gaa1 dou1 jiu3 sau1 fai3

有幾間系有線廣播噶，都要收費。