[vlc-devel] [PATCH 10/12] dash: fixed buffer precision bug

[Hugo Beauzée-Luyssen]

On Tue, Mar 13, 2012 at 3:18 PM,  <Christopher at mailsrv.uni-klu.ac.at> wrote:
> From: Christopher Mueller <christopher.mueller at itec.aau.at>
>
> ---
>  modules/stream_filter/dash/buffer/BlockBuffer.cpp |   42 +++-----------------
>  modules/stream_filter/dash/buffer/BlockBuffer.h   |    2 +-
>  2 files changed, 8 insertions(+), 36 deletions(-)
>
> diff --git a/modules/stream_filter/dash/buffer/BlockBuffer.cpp b/modules/stream_filter/dash/buffer/BlockBuffer.cpp
> index 056c481..c05056d 100644
> --- a/modules/stream_filter/dash/buffer/BlockBuffer.cpp
> +++ b/modules/stream_filter/dash/buffer/BlockBuffer.cpp
> @@ -101,14 +101,14 @@ int     BlockBuffer::get                  (void *p_data, unsigned int len)
>
>     int ret = len > this->sizeBytes ? this->sizeBytes : len;
>
> -    this->reduceBufferMilliSec(ret);
> -
>     if(p_data == NULL)
>         block_SkipBytes(&this->buffer, ret);
>     else
>         block_GetBytes(&this->buffer, (uint8_t *)p_data, ret);
>
>     block_BytestreamFlush(&this->buffer);
> +    this->updateBufferSize(ret);
> +
>     this->notify();
>
>     vlc_cond_signal(&this->empty);
> @@ -162,47 +162,19 @@ void    BlockBuffer::notify               ()
>     for(size_t i = 0; i < this->bufferObservers.size(); i++)
>         this->bufferObservers.at(i)->bufferLevelChanged(this->sizeMicroSec, ((float)this->sizeMicroSec / this->capacityMicroSec) * 100);
>  }
> -void    BlockBuffer::reduceBufferMilliSec (size_t bytes)
> +void    BlockBuffer::updateBufferSize     (size_t bytes)
>  {
> -    size_t  pos      = 0;
> -    float   microsec = 0;
> -
>     block_t *block = this->buffer.p_block;
>
> -    if(bytes < (block->i_buffer - this->buffer.i_offset))
> -    {
> -        pos = bytes;
> -        microsec = ((float)block->i_length / block->i_buffer) * bytes;
> -    }
> -    else
> -    {
> -        pos = block->i_buffer - this->buffer.i_offset;
> -        microsec = ((float)block->i_length / block->i_buffer) * (block->i_buffer - this->buffer.i_offset);
> -    }
> +    this->sizeMicroSec = 0;
>
> -    while(pos < bytes)
> +    while(block)
>     {
> +        this->sizeMicroSec += block->i_length;
>         block = block->p_next;
> -        if((bytes - pos) < (block->i_buffer - this->buffer.i_offset))
> -        {
> -            pos = bytes;
> -            microsec += ((float)block->i_length / block->i_buffer) * (bytes - pos);
> -        }
> -        else
> -        {
> -            pos += block->i_buffer;
> -            microsec += block->i_length;
> -        }
>     }
>
> -    this->sizeMicroSec  -= microsec;
> -    this->sizeBytes     -= bytes;
> -
> -    if(this->sizeMicroSec < 0)
> -        this->sizeMicroSec = 0;
> -
> -    if(this->sizeBytes == 0)
> -        this->sizeMicroSec = 0;
> +    this->sizeBytes -= bytes;
>  }
>  mtime_t BlockBuffer::size                 ()
>  {
> diff --git a/modules/stream_filter/dash/buffer/BlockBuffer.h b/modules/stream_filter/dash/buffer/BlockBuffer.h
> index 570861f..06a35fc 100644
> --- a/modules/stream_filter/dash/buffer/BlockBuffer.h
> +++ b/modules/stream_filter/dash/buffer/BlockBuffer.h
> @@ -69,7 +69,7 @@ namespace dash
>
>                 std::vector<IBufferObserver *> bufferObservers;
>
> -                void reduceBufferMilliSec(size_t bytes);
> +                void updateBufferSize(size_t bytes);
>         };
>     }
>  }
> --
> 1.7.0.4
>
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Can't this be avoided by keeping the ammount of available bytes in a
BlockBuffer attribute?

-- 
Hugo Beauzée-Luyssen