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Editorial Team
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Asked: 2026-05-19T13:25:09+00:00

I’m having issues with playing back some quick time files using actionscript 3.0 (

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I’m having issues with playing back some quick time files using actionscript 3.0 (NetStream class).

I have no control on how the quick time files are produced, but it seems so far that the files with uncompressed audio do not play audio at all in Flash Player.

I’m trying to compile a list of audio formats using video(mov/flv/etc.) in Flash Player, but I’m confused by the resources.

I’ve look through the FLV Format Specs(pdf link) on devnet and the media types listed there are:

MP3 A media type of .mp3 (0x2E6D7033)
indicates that the track contains MP3
audio data. The dot character, hex
0x2E, is included to make a complete
four-character code.

AAC A media type
of mp4a (0x6D703461) indicates that
the track is encoded with AAC audio.
Flash Player supports the following
AAC profiles, denoted by their object
types:
– 1 = main profile
– 2 = low complexity, a.k.a. LC
– 5 = high efficiency/scale band replication, a.k.a. HE/SBR When the
audio codec is AAC, an esds box occurs
inside the stsd box of a sample table.
This box contains initialization data
that an AAC decoder requires to decode
the stream. See ISO/IEC 14496-3 for
more information about the structure
of this box.

On the wikipedia entry, there is a mention on uncompressed audio:

FLV files also support uncompressed
audio or ADPCM format audio.

but there is no reference for that statement.

Is there a page that lists all the supported audio formats for playing back video in Flash Player ?

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1 Answer

  1. Editorial Team

    Be careful not to confuse the F4V and FLV container formats.

    The official specification you mentioned describes both of these formats.

    Your quote specifically refers to the F4V format which only supports MP3 and AAC in the flash player.

    The list of audio codecs supported by the FLV container is shown on page 70 in the same file:

    SoundFormat
(See notes following 
table, for special 
encodings)
UB [4] 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.
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