Adobe Flash Video File Format Specification Version 10.1 ide
File Tag包括Tag Header和Tag Data兩部分。不一樣類型的Tag的Header結構是相同的,可是Data結構各不相同編碼
File Tag Header數據。spa
當前版本的Tag Header結構佔用11個字節,如上圖綠色部分所示:code
第1個字節表示Tag類型,包括音頻(0x08)、視頻(0x09)和script data(0x12),其餘類型值被保留。 即爲0x08orm
第2-4字節爲UI24類型的值,表示該Tag Data部分的大小。 即爲0x0C=12視頻
第5-7字節爲UI24類型的值,表示該Tag的時間戳(單位爲ms),第一個Tag的時間戳老是0。即爲0x74=116,此時間戳表示解碼時間!!!ip
第8個字節爲時間戳的擴展字節,當24位數值不夠時,該字節做爲最高位將時間戳擴展爲32位值。 即爲0x00ci
第9-11字節爲UI24類型的值,表示stream id,老是0. 即爲0x00it
Audio Tag Header數據:io
Format of SoundData. The following values are defined:
0 = Linear PCM, platform endian
1 = ADPCM
2 = MP3
3 = Linear PCM, little endian
4 = Nellymoser 16 kHz mono
5 = Nellymoser 8 kHz mono
6 = Nellymoser
7 = G.711 A-law logarithmic PCM
8 = G.711 mu-law logarithmic PCM
9 = reserved
10 = AAC
11 = Speex
14 = MP3 8 kHz
15 = Device-specific sound
Formats 7, 8, 14, and 15 are reserved.
AAC is supported in Flash Player 9,0,115,0 and higher.
Speex is supported in Flash Player 10 and higher.
上圖中值爲0xA,即音頻爲AAC編碼
Sampling rate. The following values are defined:
0 = 5.5 kHz
1 = 11 kHz
2 = 22 kHz
3 = 44 kHz
上圖中值爲3,即採樣率爲44kHz
Size of each audio sample. This parameter only pertains to
uncompressed formats. Compressed formats always decode
to 16 bits internally.
0 = 8-bit samples
1 = 16-bit samples
上圖中值爲1,即16 bit採樣
Mono or stereo sound
0 = Mono sound
1 = Stereo sound
上圖中值爲1,即爲立體聲