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

[Michael Niedermayer]

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
[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Those who are too smart to engage in politics are punished by being
governed by those who are dumber. -- Plato 
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