[FFmpeg-devel] [PATCH] 1bpp and 2bpp support in QTRLE

[Stefan Gehrer]

Michael Niedermayer wrote:
> On Sun, Aug 31, 2008 at 12:13:13PM +0200, Stefan Gehrer wrote:
>> Hi,
>>
>> patch is based on Roberto's patch here
>> (http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2007-January/022046.html)
>> and adds support for 1bpp and 2bpp decoding in qtrle.c.
>> The samples from http://samples.mplayerhq.hu/V-codecs/QTRLE/
>> play visually ok, but the 1bpp decoding produces warnings
>> about trying to write pixels past the end of the image.
>>
>> Stefan
> 
>> Index: qtrle.c
>> ===================================================================
>> --- qtrle.c	(revision 15121)
>> +++ qtrle.c	(working copy)
> 
> [...]
> 
>>  static void qtrle_decode_2bpp(QtrleContext *s, int stream_ptr, int row_ptr, int lines_to_change)
>>  {

[snip]

>>  }
> 
> this looks like it can be in a common function handling 4bpp as well.
> it that is marked as inline gcc should optimize the bpp out.
> 

Done, new patch attached.

> 
>> @@ -387,6 +485,7 @@
>>      QtrleContext *s = avctx->priv_data;
>>      int header, start_line;
>>      int stream_ptr, height, row_ptr;
>> +    int has_palette = 0;
>>  
>>      s->buf = buf;
>>      s->size = buf_size;
>> @@ -433,28 +532,19 @@
>>      case 2:
>>      case 34:
>>          qtrle_decode_2bpp(s, stream_ptr, row_ptr, height);
>> +        has_palette = 1;
>>          break;
>>  
>>      case 4:
>>      case 36:
>>          qtrle_decode_4bpp(s, stream_ptr, row_ptr, height);
>> -        /* make the palette available on the way out */
>> -        memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
>> -        if (s->avctx->palctrl->palette_changed) {
>> -            s->frame.palette_has_changed = 1;
>> -            s->avctx->palctrl->palette_changed = 0;
>> -        }
>> +        has_palette = 1;
>>          break;
>>  
>>      case 8:
>>      case 40:
>>          qtrle_decode_8bpp(s, stream_ptr, row_ptr, height);
>> -        /* make the palette available on the way out */
>> -        memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
>> -        if (s->avctx->palctrl->palette_changed) {
>> -            s->frame.palette_has_changed = 1;
>> -            s->avctx->palctrl->palette_changed = 0;
>> -        }
>> +        has_palette = 1;
>>          break;
>>  
>>      case 16:
>> @@ -474,6 +564,16 @@
>>              avctx->bits_per_sample);
>>          break;
>>      }
>> +
>> +    if(has_palette) {
>> +        /* make the palette available on the way out */
>> +        memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
>> +        if (s->avctx->palctrl->palette_changed) {
>> +            s->frame.palette_has_changed = 1;
>> +            s->avctx->palctrl->palette_changed = 0;
>> +        }
>> +    }
>> +
>>  done:
>>      *data_size = sizeof(AVFrame);
>>      *(AVFrame*)data = s->frame;
> 
> The avctx->palctrl->palette_changed stuff is deprecated due to race
> conditions caused by the design.

I see, though I consider this patch independent of the issue as it only
moves the code to a common place.
As far as I can see the deprecated way of handling palettes must be
fixed in the MOV demuxer first.

Stefan
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