He aha te whakakōwae ataata H.264? Me pēhea te mahi a te kōteke H.264?

Kua tere te whanaketanga o te hangarau ataata i ngā tekau tau kua pahure ake nei. I mua, i hangaia ngā ataata mai i ngā kohinga nui o ngā whakaahua tonu, ā, i whakamahia ngā kōnae nunui rawa hei hanga mamati. Engari i nāianei, kua kawea mai e te whakawaehere ataata he panoni hangarau – te kōpeke i ēnei kōnae kia iti ake te wāhi e pau ana. Kua taea hoki te rere ataata i runga i te Ipurangi, i te wā tūturu me te wā e hiahiatia ana.

Ko tētahi o ngā hangarau whakakōwae rongonui ko te H.264 (AVC – Advanced Video Coding) kua taea e ia te whakaoti i ngā take kounga maha e pā ana ki te whakapāho ataata. I roto i te tuhinga o te rā nei, me ako tātou he aha te whakakōwae ataata H.264, me pēhea tana mahi, me ōna painga.

He aha te H.264/AVC?

Ko te H.264 e kiia ana ko te Advanced Video Coding (AVC) ko te MPEG-4 Wāhanga 10 rānei. He hangarau kōpeketanga ataata i whakawhanakehia ngātahitia e te International Telecommunications Union (hei H.264) me te International Organization for Standardization/International Electrotechnical Commission Moving Picture Experts Group (hei MPEG-4 Wāhanga 10, Advanced Video Coding, AVC rānei).

I ēnei rā, ko te kōteke H.264 te mea e whakamahia whānuitia ana i roto i te rere ataata. He paerewa ahumahi tēnei kōteke mō te kōpeketanga ataata e āwhina ana i ngā kaihanga ki te tuhi, ki te kōpeke, me te tohatoha i ā rātou ataata ipurangi. He kounga ataata pai tana e tukuna ana i ngā tere bitrate iti iho i ngā paerewa o mua. Nō reira, he whānuitia te whakamahinga i roto i te pāpāho pouaka whakaata taura me ngā kōpae Blu-ray.

Hei kōteke ataata, he maha ngā wā ka hangaia te H.264 i roto i te whakatakotoranga ipu MPEG-4, e whakamahi ana i te toronga .MP4, me te QuickTime (.MOV), Flash (.F4V), 3GP mō ngā waea pūkoro (.3GP), me te awa kawe MPEG (.ts). I ētahi wā, ka whakakōtekehia he ataata H.264 me te oro kua kōpeketia ki te kōteke Whakakōteke Oro Matatau (AAC), he paerewa ISO/IEC (MPEG4 Wāhanga 3).

Me pēhea te mahi a te H.264/AVC?

Ka whakahaerehia e te kaikōwae ataata H.264 ngā tukanga matapae, whakawhiti, me te whakakōwae hei whakaputa i tētahi awa moka H.264 kua kōpeketia. Ka whakamahia e ia he paerewa poraka-arotahi me te whakataetae nekehanga hei tukatuka i ngā anga o ngā ihirangi ataata. Ko te putanga he poraka nui kei roto ko ngā rahi poraka he 16×16 pika te rahi.

Ināianei, ka mahi te pūwetewete ataata H.264 i ngā tukanga tautoko pēnei i te wetewete, te hurihanga whakamuri, me te hanga anō hei whakaputa i tētahi raupapa ataata kua wetewetehia. Ka whiwhi ia i te awa moka H.264 kua kōpeketia, ka wetewete i ia huānga wetereo, ā, ka tango i ngā mōhiohio pēnei i ngā taunga hurihanga kua whakarārangihia, ngā mōhiohio matapae, me ētahi atu. Hei tāpiri, ka whakamahia ēnei mōhiohio hei huri i te tukanga waehere me te hanga anō i tētahi raupapa o ngā whakaahua ataata. Kei raro nei te tukanga waehere me te wetewete ataata H.264.

Ngā Painga o H.264

1.He iti ake te whakamahinga o te whānui o te hononga me te aroturukitanga taumira teitei ake – Ka whakarato i te tuku kounga teitei o te ataata nekehanga-katoa me ngā whakaritenga whānui iti ake me te iti ake o te whakaroa i tengā paerewa ataata tuku ihopērā i te MPEG-2. Ka whakamahia e te H.264 tētahi kōteke whai hua e whakarato ana i ngā whakaahua kounga teitei, ā, he iti noa te whānui o te hononga e whakamahia ana.

2.He iti ake te tere moka H.264 i ērā atu hōputu – He 80% te iti iho o tōna tere moka i te ataata Motion JPEG. E kiia ana ko te penapena tere moka ka taea te 50%, neke atu rānei, ki te whakatauritea ki te MPEG-2. Hei tauira, ka taea e te H.264 te whakarato i te kounga ahua pai ake i te tere moka kua kōpekehia. I te tere moka iti iho, ka whakaratohia e ia te kounga ahua rite tonu.

3.Te whakaiti i te hiahia mō te rokiroki ataata – Ka whakaitihia te rahi o te ihirangi kōnae ataata mamati mā te 50%, ā, ka iti ake te rokiroki e whakamahia ana hei rokiroki ataata, ki te whakaritea ki ētahi atu paerewa e whakaatu ana i te hiranga hei ngāwari i te tuku ataata mā te IP.

4.He kounga ataata whakamiharo – Ka tukuna he ihirangi ataata mārama, kounga teitei i te tere raraunga o te ¼, he haurua te rahi o te hōputu ataata kē atu.

5.He pai ake te mahi – E rua ngā wā he pai ake, ā, e toru ngā wā he iti ake te rahi o te kōnae i ngā kōtēke MPEG-2 – ā, he pai ake te mahi o tēnei hōputu kōpeketanga. Nā tēnei kōtēke ka iti te whānui o te tuku mō ngā ihirangi ataata.

6.He pai mō ngā ihirangi ataata nekehanga puhoi – He tino whai hua mō ngā kōtēke ataata nekehanga iti e whakamahi ana i ngā kāmera megapixel.