HI Josh, I'm starting now to compile the ACM codec. I don't know how long it will take, since I do it in my free time, but I guess it will not take to long. About Mark Powell's comment, with an ACM codec there will be a lot of Windows GUIs for FLAC. I'm writing this message to talk about the FLAC format. The GUIs for the Audio Codec Manager, including Winamp and Windows Media Player for decoding and CodAxe for encoding, can use any format with a codec registered in the system using the RIFF file format. In this ACM codec's implementation, all data, including the "fLaC" marker and the metadata blocks, is placed by the Audio Codec Manager encoder's GUI in the RIFF's data area. Actually, I couldn't find any other way for doing this. The inconvenient is that the files written this way can't be read by any other than the Audio Codec Manager. I have two suggestions to solve this problem: the reference decoder could be modified to understand the RIFF structure or the FLAC format could be changed to meet the RIFF format. The first solution's inconvenient is that there will be some data repeated, which is not a good idea in a compression format. I don't know if the amount of space waste is relevant here. The second solution's inconvenient is that a format change will break the compatibility with previous versions. It's not good either. What do you think? Another thing: it will be necessary to register the wave format, the manufacturer id and the product id with Microsoft. It's a little hard for me to do this here from Brazil. Are you in USA? You can keep the ACM codec's copyright, I just want my name in the code files as the original developer. Regards, Daniel
Hi,> I'm starting now to compile the ACM codec. I don't know how long it will > take, since I do it in my free time, but I guess it will not take to long. > About Mark Powell's comment, with an ACM codec there will be a lot of > Windows GUIs for FLAC. > I'm writing this message to talk about the FLAC format. The GUIs for the > Audio Codec Manager, including Winamp and Windows Media Player for decoding > and CodAxe for encoding, can use any format with a codec registered in the > system using the RIFF file format. In this ACM codec's implementation, all > data, including the "fLaC" marker and the metadata blocks, is placed by the > Audio Codec Manager encoder's GUI in the RIFF's data area. Actually, I > couldn't find any other way for doing this. The inconvenient is that the > files written this way can't be read by any other than the Audio Codec > Manager.That's what I wanted to say a month ago.> I have two suggestions to solve this problem: the reference decoder could be > modified to understand the RIFF structure or the FLAC format could be > changed to meet the RIFF format. The first solution's inconvenient is that > there will be some data repeated, which is not a good idea in a compression > format. I don't know if the amount of space waste is relevant here. The > second solution's inconvenient is that a format change will break the > compatibility with previous versions. It's not good either. What do you > think?Using a WAV file makes the thing not streamable, unless the RIFF structure isn't checked. But you can't guarantee that.> Another thing: it will be necessary to register the wave format, the > manufacturer id and the product id with Microsoft. It's a little hard for me > to do this here from Brazil. Are you in USA? You can keep the ACM codec's > copyright, I just want my name in the code files as the original developer.Have you tried to use a WAVEFORMATEXTENSIBLE? This should make registration obsolete. Regards, Ingo
Hi Daniel,> I'm writing this message to talk about the FLAC format. The GUIs for the > Audio Codec Manager, including Winamp and Windows Media Player for decoding > and CodAxe for encoding, can use any format with a codec registered in the > system using the RIFF file format. In this ACM codec's implementation, all > data, including the "fLaC" marker and the metadata blocks, is placed by the > Audio Codec Manager encoder's GUI in the RIFF's data area. Actually, I > couldn't find any other way for doing this. The inconvenient is that the > files written this way can't be read by any other than the Audio Codec > Manager.another question. Does FLAC need the metadata at the beginning of a file. Assume you open a FLAC file in VirtualDub, for example. When you cut out the first half of the WAV and the write out an AVI, the first half of the data is missing, which includes the fLaC magic number and the metadata. Is this file still readable then? I think you should put the marker and the metadata into the WAVEFORMATEX (or WAVEFORMATEXTENSIBLE). I don't know if you do this, but you said, that all data is placed in the data area. Regards, Ingo
--- Ingo Ralf Blum <ingoralfblum@gmx.de> wrote:> another question. Does FLAC need the metadata at the beginning of a > file. Assume > you open a FLAC file in VirtualDub, for example. When you cut out the > first half > of the WAV and the write out an AVI, the first half of the data is > missing, > which includes the fLaC magic number and the metadata. Is this file > still > readable then? I think you should put the marker and the metadata > into the > WAVEFORMATEX (or WAVEFORMATEXTENSIBLE).the magic number and STREAMINFO metadata block are mandatory. some of the fields are allowed to be 0 to specify that the values are unknown; check the format page for the full info: http://flac.sourceforge.net/format.html#metadata_block_streaminfo I would hope that the act of cutting can trigger some programmable piece of code in the filter that can create the new STREAMINFO block and prepend it. Josh __________________________________________________ Do You Yahoo!? Listen to your Yahoo! Mail messages from any phone. http://phone.yahoo.com