Fw: [Mp4-tech] Fw: Regarding codecs supported by Mp4 file format

[Gomathi R]

----- Original Message ----- 
From: Gomathi R 
To: Girish Shenoy 
Sent: Friday, October 13, 2023 12:11 PM
Subject: Re: [Mp4-tech] Fw: Regarding codecs supported by Mp4 file format
Hi Girish,
Thanx a lot for ur reply....
In Mp4 file format doc(14496-14) they didn't mention that these are the specific codecs supported...again while surfing, i got to know in mp4 file we can put any stream inside it.if that is the case it will be a very tedious work to go through all the codec headers n all.
I too believe whatever you mentioned are the streams supported.In this case also when i referred the mpeg-4 systems doc. there is no reference for mpeg1/2 video.For mpeg 4 video they mentioned to refer 14496-2 Annex-k.But for Mpeg 1/2 video how to write the header info ? where to refer..?
Also while referring mpeg-4 audio doc the AudioObjectType in AudioSpecificConfig contains CELP,HVXC,TwinVQ....etc..... should i need to support that also.if it is so CELP,TwinVQ are seperate coders to give them the DecoderSpecificInfo as header and encoded samples after that?.....Dont get tensed on seeing these many questions.....Please clarify me if u have free time.......
Thanks a lot
Regards
Gomathi.
  ----- Original Message ----- 
  From: Girish Shenoy 
  To: Gomathi R 
  Sent: Friday, October 13, 2023 11:38 AM
  Subject: RE: [Mp4-tech] Fw: Regarding codecs supported by Mp4 file format
  Hi Gomathi,
  To my knowledge .mp4 supports mpeg 1/2/4 audio/video/systems streams (and also jpeg-1 streams i believe).
  To figure out which one of these is in use, one has to look at the ObjectTypeIndication.
  To figure out what are the headers (decoder specific info), unfortunately, one has to refer to that specific standard (eg 14496-2 for mpeg-4 visual). Hence in order to be able to decode all streams one has to have access to all of the above standards.
  Regards,
  Girish
  -----Original Message-----
  From: Gomathi R [mailto:rgomathi sarayusoftech.com]
  Sent: Friday, October 13, 2023 11:13 AM
  To: Girish Shenoy
  Subject: Re: [Mp4-tech] Fw: Regarding codecs supported by Mp4 file format
  Hi Girish,
  Thank u very much for ur reply.......
  yaa i had taken the information from other atoms like stco,stsc to correctly locate the encoded data address in the mdat area.
  But my problem is with the header we have to include in front of encoded streams.For that first I should know what are all the codecs supported by a standard mp4 file.
  Then I have to study  whether for a particular encoded stream we need to include header or not.B''coz for mpeg 1/2 Audio layers there is no DecoderSpecificInfo ,so,no need to include headers as the encoded stream itself contains all the info needed for the decoder.This all about my problem . 
  Please help me out 
  Expecting replies.....
  Thanks n Regards
  Gomathi.
    ----- Original Message ----- 
    From: Girish Shenoy 
    To: Gomathi R 
    Sent: Friday, October 13, 2023 10:40 AM
    Subject: RE: [Mp4-tech] Fw: Regarding codecs supported by Mp4 file format
    Hi Gomathi,
    ObjectTypeIndication is the right place to look for the information you need. You've already hit the nail on the head.
    But please be aware that the mdat need not necessarily be directly decodable without the help of other boxes in the file. Especially in the case where the file has more than one stream, the mdat may have data from both streams interleaved with each other.
    Regards,
    Girish
    -----Original Message-----
    From: mp4-tech-bounces lists.mpegif.org [mailto:mp4-tech-bounces lists.mpegif.org]On Behalf Of Gomathi R
    Sent: Wednesday, October 11, 2023 9:01 AM
    To: mp4-tech lists.mpegif.org
    Subject: Re: [Mp4-tech] Fw: Regarding codecs supported by Mp4 file format
    Thanks a lot Liang.....
    Actually I'm going to parse the .mp4 file and have to extract audio n video streams seperately to give as input to the corresponding decoders.ie.I'm going to write the code for Mp4 parser according to 14496-part 14.
    so for example if the .mp4 contains mpeg-4 video i will read 0x20 as ObjectTypeIndication,then i ll extract the DecoderSpecificInfo as the header for .m4v file(as per 14496-2) and after that i will simply put the encoded samples from the "mdat" area.SO, if the codecs are predefined then i can study about their header info .If the case is like this how should i proceed....Please tell me some suggestions.......
    Thanks & Regards
    Gomathi.
      ----- Original Message ----- 
      From: Dickson Liang 
      To: Gomathi R 
      Sent: Tuesday, October 10, 2023 9:10 PM
      Subject: Re: [Mp4-tech] Fw: Regarding codecs supported by Mp4 file format
      Hi,
      MP4 is a file container. So in theory and in practical, you can put almost any kinds of MPEG-related codec inside this format. For example, you can put MPEG2 layer2 audio and MPEG4 H264 video into the same MP4 file. Just like a bag -- you can put any codec you like into the MP4 container.
      Regards,
      Dickson Liang
      Gomathi R <rgomathi sarayusoftech.com> wrote:
        ----- Original Message ----- 
        From: Gomathi R 
        To: mp4-tech lists.mpegif.org 
        Sent: Tuesday, October 10, 2023 12:33 PM
        Subject: Regarding codecs supported by Mp4 file format
        Hi all...
        I'm new to this group and this mail is regarding codecs supported by mp4 file format.
        I've reffered ISO/IEC 14496-part 14(Mp4 - File Format) where they simply mentioned as AudioSampleEntry,VideoSampleEntry...but i want the actual codecs supported from standard reference......
        Please help me out...
        Thanks in Advance
        Please reply ASAP......
        Cheers,
        Gomathi.
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