FFmpeg在Android多媒體平臺下的編碼優(yōu)化研究
發(fā)布時間：2019-04-24 12:01
【摘要】：在移動互聯(lián)網(wǎng)飛速發(fā)展的現(xiàn)今,人們對移動終端的需求不再滿足于發(fā)短信和通電話了,越來越多的人都將手機(jī)作為了日常生活的消遣和娛樂工具。伴隨著智能手機(jī)的普及以及性能的提高,多媒體應(yīng)用也層出不窮,可以說在未來的移動互聯(lián)網(wǎng)領(lǐng)域中,多媒體應(yīng)用將占據(jù)著舉足輕重的地位。Android智能手機(jī)作為移動互聯(lián)網(wǎng)的載體,是目前最為流行的智能手機(jī)之一,其在全球的市場份額已經(jīng)達(dá)到了78.1%,因此吸引了很多的開發(fā)者投向Android陣型。然而,Android系統(tǒng)上層的多媒體接口并沒有像它的市場份額一樣發(fā)展迅速,很多涉及到多媒體流式傳輸和可視化通信的應(yīng)用都是基于Android底層開發(fā),開發(fā)者首先需要熟悉Android的底層代碼,而不同開發(fā)者又有不同的實(shí)現(xiàn)方式。這樣的結(jié)果導(dǎo)致了Android多媒體應(yīng)用的開發(fā)難度大,開發(fā)周期長。 為了實(shí)現(xiàn)一個通用的Android多媒體開發(fā)方案,本文將目前最為流行的音視頻編解碼庫FFmpeg整合到Android多媒體中,通過使用FFmpeg的接口來達(dá)到開發(fā)Android多媒體應(yīng)用的目的。針對于FFmpeg只能軟件編碼從而導(dǎo)致編碼效率過低的問題,本文還提出了優(yōu)化FFmpeg編碼器的方案設(shè)計(jì)。在深入理解Android多媒體編碼機(jī)制的基礎(chǔ)上,從中提取出硬件編碼器,并將其設(shè)計(jì)成插件的形式融合到FFmpeg中,實(shí)現(xiàn)高效的編碼。 為了能夠體現(xiàn)FFmpeg優(yōu)化后的編碼性能,本文設(shè)定了在三種視頻分辨率的環(huán)境下,對優(yōu)化前后的視頻編碼進(jìn)行比較。分別記錄不同分辨率下,它們的PSNR值、編碼平均效率、CPU平均使用率和內(nèi)存平均使用率。結(jié)果表明：從PSNR值可以發(fā)現(xiàn)優(yōu)化后的視頻編碼質(zhì)量要比優(yōu)化前的稍微好一些,但從視覺效果上是完全相同的。由于高負(fù)荷工作導(dǎo)致CPU平均使用率相差并不大；而在144x176分辨率下,優(yōu)化后的FFmpeg比優(yōu)化前具有高出將近8倍的編碼效率,而且分辯率越高,編碼效率相差的倍數(shù)也越高。對于內(nèi)存的平均使用率,優(yōu)化后比優(yōu)化前降低了約2倍。因此,優(yōu)化后的FFmpeg編碼器更能適用于Android平臺。
[Abstract]:Nowadays, with the rapid development of mobile Internet, the demand for mobile terminals is no longer satisfied with texting and telephone communication. More and more people use mobile phones as entertainment and entertainment tools in daily life. With the popularity of smart phones and the improvement of their performance, multimedia applications also emerge one after another. It can be said that in the future, in the field of mobile Internet, Multimedia applications will occupy an important position. As the carrier of mobile Internet, Android smartphone is one of the most popular smart phones at present, and its market share in the world has reached 78.1%. As a result, many developers are attracted to the Android formation. However, the multimedia interface in the upper layer of the Android system has not developed as rapidly as its market share. Many applications involving multimedia streaming and visual communication are based on the development of the bottom layer of Android. Developers first need to be familiar with the underlying code of Android, and different developers have different methods of implementation. As a result, the development of Android multimedia applications is difficult and the development cycle is long. In order to realize a general Android multimedia development scheme, this paper integrates the most popular audio and video coding library, FFmpeg, into Android multimedia, and uses the interface of FFmpeg to achieve the purpose of developing Android multimedia application. In view of the problem that FFmpeg can only be coded by software which leads to low coding efficiency, this paper also puts forward the scheme design of optimizing FFmpeg encoder. On the basis of deep understanding of the multimedia coding mechanism of Android, the hardware encoder is extracted from it and integrated into the form of plug-in into FFmpeg to achieve efficient coding. In order to reflect the optimized coding performance of FFmpeg, the video coding before and after optimization is compared under the environment of three kinds of video resolution. Their PSNR values, average coding efficiency, CPU average usage and memory average utilization were recorded at different resolutions. The results show that the optimized video coding quality is slightly better than that before the optimization from PSNR value, but the visual effect is exactly the same. Because of the high load work, the average utilization rate of CPU is not much different, but under the 144x176 resolution, the optimized FFmpeg has nearly 8 times higher coding efficiency than that before the optimization, and the higher the resolution rate, the higher the multiple of the difference of coding efficiency. For the average memory usage, the optimized usage is about 2 times lower than before the optimization. Therefore, the optimized FFmpeg encoder is more suitable for Android platform.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN919.81
本文編號：2464430
[Abstract]:Nowadays, with the rapid development of mobile Internet, the demand for mobile terminals is no longer satisfied with texting and telephone communication. More and more people use mobile phones as entertainment and entertainment tools in daily life. With the popularity of smart phones and the improvement of their performance, multimedia applications also emerge one after another. It can be said that in the future, in the field of mobile Internet, Multimedia applications will occupy an important position. As the carrier of mobile Internet, Android smartphone is one of the most popular smart phones at present, and its market share in the world has reached 78.1%. As a result, many developers are attracted to the Android formation. However, the multimedia interface in the upper layer of the Android system has not developed as rapidly as its market share. Many applications involving multimedia streaming and visual communication are based on the development of the bottom layer of Android. Developers first need to be familiar with the underlying code of Android, and different developers have different methods of implementation. As a result, the development of Android multimedia applications is difficult and the development cycle is long. In order to realize a general Android multimedia development scheme, this paper integrates the most popular audio and video coding library, FFmpeg, into Android multimedia, and uses the interface of FFmpeg to achieve the purpose of developing Android multimedia application. In view of the problem that FFmpeg can only be coded by software which leads to low coding efficiency, this paper also puts forward the scheme design of optimizing FFmpeg encoder. On the basis of deep understanding of the multimedia coding mechanism of Android, the hardware encoder is extracted from it and integrated into the form of plug-in into FFmpeg to achieve efficient coding. In order to reflect the optimized coding performance of FFmpeg, the video coding before and after optimization is compared under the environment of three kinds of video resolution. Their PSNR values, average coding efficiency, CPU average usage and memory average utilization were recorded at different resolutions. The results show that the optimized video coding quality is slightly better than that before the optimization from PSNR value, but the visual effect is exactly the same. Because of the high load work, the average utilization rate of CPU is not much different, but under the 144x176 resolution, the optimized FFmpeg has nearly 8 times higher coding efficiency than that before the optimization, and the higher the resolution rate, the higher the multiple of the difference of coding efficiency. For the average memory usage, the optimized usage is about 2 times lower than before the optimization. Therefore, the optimized FFmpeg encoder is more suitable for Android platform.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN919.81
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