[vlc-devel] [vlc-commits] packetizer/dts_header: add an helper that converts 14bit words to 16bit

[Thomas Guillem]

On Wed, Jul 11, 2018, at 13:36, Thomas Guillem wrote:
> vlc | branch: master | Thomas Guillem <thomas at gllm.fr> | Tue Jul 10 
> 18:37:30 2018 +0200| [d701887137e647ecbb0512912b0069367c4bbb80] | 
> committer: Thomas Guillem
> 
> packetizer/dts_header: add an helper that converts 14bit words to 16bit
> 
> cf. https://wiki.multimedia.cx/index.php/DTS#14-bit_words
> 
> > http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=d701887137e647ecbb0512912b0069367c4bbb80
> ---
> 
>  modules/packetizer/dts_header.c | 24 ++++++++++++++++++++++++
>  modules/packetizer/dts_header.h |  5 +++++
>  2 files changed, 29 insertions(+)
> 
> diff --git a/modules/packetizer/dts_header.c b/modules/packetizer/dts_header.c
> index 36dd8bac5b..943b062036 100644
> --- a/modules/packetizer/dts_header.c
> +++ b/modules/packetizer/dts_header.c
> @@ -286,6 +286,7 @@ static int dts_header_ParseCore( vlc_dts_header_t *p_header,
>      bool b_lfe = i_lff == 1 || i_lff == 2;
>  
>      p_header->b_substream = false;
> +    p_header->b_14b = b_14b;
>      p_header->i_rate = dca_get_samplerate( i_sfreq );
>      p_header->i_bitrate = dca_get_bitrate( i_rate );
>      p_header->i_frame_size = !b_14b ? ( i_fsize + 1 )
> @@ -303,6 +304,29 @@ static int dts_header_ParseCore( vlc_dts_header_t 
> *p_header,
>      return VLC_SUCCESS;
>  }
>  
> +ssize_t vlc_dts_header_Convert14b16b( void *p_dst, size_t i_dst,
> +                                      const void *p_src, size_t i_src,
> +                                      bool b_out_le )
> +{
> +    size_t i_size = i_src * 14 / 16;
> +    if( i_src <= VLC_DTS_HEADER_SIZE || i_size > i_dst )
> +        return -1;
> +
> +    enum dts_bitsteam_type bitstream_type;
> +    if( !dts_header_IsSync( p_src, &bitstream_type ) )
> +        return -1;
> +
> +    if( bitstream_type != DTS_SYNC_CORE_14BITS_BE
> +     && bitstream_type != DTS_SYNC_CORE_14BITS_LE )
> +        return -1;
> +
> +    int i_ret = Buf14To16( p_dst, p_src, i_src,
> +                           bitstream_type == DTS_SYNC_CORE_14BITS_LE );
> +    if( b_out_le ) /* since Buf14To16 convert to BE */
> +        swab( p_dst, p_dst, i_ret );


ooops, calling swab with overlapping pointers.

Doing a fix.

> +    return i_ret;
> +}
> +
>  int vlc_dts_header_Parse( vlc_dts_header_t *p_header,
>                            const void *p_buffer, size_t i_buffer)
>  {
> diff --git a/modules/packetizer/dts_header.h b/modules/packetizer/dts_header.h
> index 6787161cd9..cdf9053ee5 100644
> --- a/modules/packetizer/dts_header.h
> +++ b/modules/packetizer/dts_header.h
> @@ -31,6 +31,7 @@
>  typedef struct
>  {
>      bool            b_substream;
> +    bool            b_14b;
>      unsigned int    i_rate;
>      unsigned int    i_bitrate;
>      unsigned int    i_frame_size;
> @@ -43,3 +44,7 @@ int     vlc_dts_header_Parse( vlc_dts_header_t *p_header,
>                                const void *p_buffer, size_t i_buffer);
>  
>  bool    vlc_dts_header_IsSync( const void *p_buffer, size_t i_buffer );
> +
> +ssize_t vlc_dts_header_Convert14b16b( void *p_dst, size_t i_dst,
> +                                      const void *p_src, size_t i_src,
> +                                      bool b_out_le );
> 
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