I need to accomplish this with Java code only, so ffmpeg and other
solutions that use native libraries aren't an option.
Thanks.
Kastellanos Nikos wrote:
An alternative strategy could be to use ffmpeg to transcode flv into mp3.
The real challenge is to find a recent compiled executable that
support the Nellymoser/ Speex (assuming that the source is the user mic).
*From:* [email protected]
[mailto:[email protected]] *On Behalf Of *Jeff Ramin
*Sent:* Wednesday, November 18, 2009 12:37 AM
*To:* Open Source Flash Mailing List
*Subject:* [osflash] flv file format question
I want to read an FLV file for the purpose of transcoding the audio,
and I'm using classes from the red5 project to iterate through the
tags in the file.
The section of the http://osflash.org/flv page on audio states:
*FLV* Tag 0x08: AUDIO
The first byte of an audio packet contains bitflags that describe the
codec used, with the following layout:
*Name *
*Expression *
*Description *
soundType
(byte & 0×01) » 0
0: mono, 1: stereo
soundSize
(byte & 0×02) » 1
0: 8-bit, 1: 16-bit
soundRate
(byte & 0x0C) » 2
0: 5.5 kHz, 1: 11 kHz, 2: 22 kHz, 3: 44 kHz
soundFormat
(byte & 0xf0) » 4
0: Uncompressed, 1: ADPCM, 2: MP3, 5: Nellymoser 8kHz mono, 6:
Nellymoser, 11: Speex
The rest of the audio packet is simply the relevant data for that
format, as per a SWF <http://osflash.org/swf> SoundStreamBlock.
However, when I dump the first few bytes of audio data from
consecutive tags,
I see this pattern:
tag 1: b2 2a d7 5b
tag 2: b2 2a d7 5a
tag 3: b2 2a d7 5a
tag 4: b2 2a d7 5a
It seems there is more header data than a single byte. Is anybody familiar
with FLV file formats and audio data (speex encoded, in this instance)
that
could clear this up for me?
Thanks.
--
Jeff Ramin
Software Engineer
Singlewire Software
PO Box 46218
Madison, WI 53744-6218
Phone Direct - 608.298.1024
www.singlewire.com <http://www.singlewire.com>
------------------------------------------------------------------------
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osflash mailing list
[email protected]
http://osflash.org/mailman/listinfo/osflash_osflash.org
--
Jeff Ramin
Software Engineer
Singlewire Software
PO Box 46218
Madison, WI 53744-6218
Phone Direct - 608.298.1024
www.singlewire.com
_______________________________________________
osflash mailing list
[email protected]
http://osflash.org/mailman/listinfo/osflash_osflash.org
