[FFmpeg-devel] Add waveformat extensible support in wav muxer (SoC qualification task)

[zhentan feng]

Hi

2009/4/3 Michael Niedermayer <michaelni at gmx.at>

> On Fri, Apr 03, 2009 at 01:25:37AM +0800, zhentan feng wrote:
> [...]
> > new patch attached below.
> >
> > zhentan
> > --
> > Best wishes~
>
> > Index: libavformat/riff.c
> > ===================================================================
> > --- libavformat/riff.c        (revision 18184)
> > +++ libavformat/riff.c        (working copy)
> > @@ -282,18 +282,34 @@
> >  int put_wav_header(ByteIOContext *pb, AVCodecContext *enc)
> >  {
> >      int bps, blkalign, bytespersec;
> > +    int waveformatextensible;
> >      int hdrsize = 18;
> > +    int pre_size = 0;
> >
> >      if(!enc->codec_tag || enc->codec_tag > 0xffff)
> >          return -1;
> >
> > -    put_le16(pb, enc->codec_tag);
> > +    waveformatextensible = enc->channels > 2 && enc->channel_layout;
> > +    if (waveformatextensible) {
> > +        put_le16(pb, 0xfffe);
> > +        pre_size = 22; /* 22 is the size of
> WAVEFORMATEXTENSIBLE-WAVEFORMATEX */
> > +    } else
> > +        put_le16(pb, enc->codec_tag);
> > +
> >      put_le16(pb, enc->channels);
> >      put_le32(pb, enc->sample_rate);
> >      if (enc->codec_id == CODEC_ID_MP2 || enc->codec_id == CODEC_ID_MP3
> || enc->codec_id == CODEC_ID_GSM_MS) {
> >          bps = 0;
> > +        if (enc->codec_id == CODEC_ID_MP2) {
> > +            pre_size += 22; /* wav_extra_size */
> > +        } else if(enc->codec_id == CODEC_ID_MP3) {
> > +            pre_size += 12; /* wav_extra_size */
> > +        } else
> > +            pre_size += 2; /* wav_extra_size */
> >      } else if (enc->codec_id == CODEC_ID_ADPCM_IMA_WAV || enc->codec_id
> == CODEC_ID_ADPCM_MS || enc->codec_id == CODEC_ID_ADPCM_G726 ||
> enc->codec_id == CODEC_ID_ADPCM_YAMAHA) { //
> >          bps = 4;
> > +        if (enc->codec_id == CODEC_ID_ADPCM_IMA_WAV)
> > +            pre_size += 2; /* wav_extra_size */
> >      } else {
> >          if (!(bps = av_get_bits_per_sample(enc->codec_id)))
> >              bps = 16; // default to 16
> > @@ -324,8 +340,30 @@
> >      put_le32(pb, bytespersec); /* bytes per second */
> >      put_le16(pb, blkalign); /* block align */
> >      put_le16(pb, bps); /* bits per sample */
> > +
> > +    if (pre_size) {
> > +        if (waveformatextensible && pre_size == 22) {
> > +            put_le16(pb, pre_size + enc->extradata_size);
> > +        } else
> > +            put_le16(pb, pre_size);
> > +    } else {
> > +        if (enc->extradata_size) {
> > +            put_le16(pb, enc->extradata_size);
> > +        } else
> > +            return hdrsize - 2;
> > +    }
> > +
>
> this is still a mess
> [...]


According to the suggestion from Ronald.
I'll submmit the patch step by step.

this patch calculate the size of the extradata_size before write extradata.
then I'll submitt the patch for adding waveformatextensible.
this would be more readable and keep my head cool :)

thanks
zhentan
-- 
Best wishes~
-------------- next part --------------
A non-text attachment was scrubbed...
Name: waveformatextensible_11.patch
Type: application/octet-stream
Size: 2785 bytes
Desc: not available
URL: <http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/attachments/20090403/673f1109/attachment.obj>