[Ffmpeg-devel] [PATCH] C93 demuxer and decoder (GSoC qualification task)

[Anssi Hannula]

Michael Niedermayer wrote:
> Hi

Hi!

> On Thu, Apr 05, 2007 at 11:39:35PM +0300, Anssi Hannula wrote:
>> Michael Niedermayer wrote:
>>> On Thu, Apr 05, 2007 at 10:36:15PM +0300, Anssi Hannula wrote:

> [...]
>> +            case C93_8X8_2COLOR:
>> +                cols[0] = *buf++;
>> +                cols[1] = *buf++;
>> +                for (j = 0; j < 8; j++) {
>> +                    for (i = 0; i < 8; i++) {
>> +                        out[(y+j)*stride+x+i] = cols[(buf[0] >> i) & 1];
>> +                    }
>> +                    buf++;
>> +                }
>> +                break;
>> +
>> +            case C93_4X4_2COLOR:
>> +                for (y_off = 0; y_off < 8; y_off += 4) {
>> +                    for (x_off = 0; x_off < 8; x_off += 4) {
>> +                        colbit = 0;
>> +                        cols[0] = *buf++;
>> +                        cols[1] = *buf++;
>> +                        colmask = bytestream_get_le16(&buf);
>> +                        for (j = 0; j < 4; j++) {
>> +                            for (i = 0; i < 4; i++) {
>> +                                out[(y+y_off+j)*stride+x+x_off+i] =
>> +                                    cols[(colmask >> colbit++) & 1];
>> +                            }
>> +                        }
>> +                    }
>> +                }
>> +                break;
>> +
>> +            case C93_4X4_4COLOR_GRP:
>> +                for (y_off = 0; y_off < 8; y_off += 4) {
>> +                    for (x_off = 0; x_off < 8; x_off += 4) {
>> +                        colbit = 0;
>> +                        bytestream_get_buffer(&buf, cols, 4);
>> +                        colmask = bytestream_get_le16(&buf);
>> +                        for (j = 0; j < 4; j++) {
>> +                            int curcols[2];
>> +                            curcols[0] = j & 2 ? cols[3] : cols[0];
>> +                            for (i = 0; i < 4; i++) {
>> +                                curcols[1] = i & 2 ? cols[2] : cols[1];
>> +                                out[(y+y_off+j)*stride+x+x_off+i] =
>> +                                    curcols[(colmask >> colbit++) & 1];
>> +                            }
>> +                        }
>> +                    }
>> +                }
>> +                break;
>> +
>> +            case C93_4X4_4COLOR:
>> +                for (y_off = 0; y_off < 8; y_off += 4) {
>> +                    for (x_off = 0; x_off < 8; x_off += 4) {
>> +                        colbit = 0;
>> +                        bytestream_get_buffer(&buf, cols, 4);
>> +                        colmask = bytestream_get_le32(&buf);
>> +                        for (j = 0; j < 4; j++) {
>> +                            for (i = 0; i < 4; i++) {
>> +                                out[(y+y_off+j)*stride+x+x_off+i] =
>> +                                    cols[(colmask >> colbit) & 3];
>> +                                colbit += 2;
>> +                            }
>> +                        }
> 
> the 2/4 color block draw code seems to occur 4 times, maybe that could be
> simplfied?

Yes, not very straight-forwardly, though. Anyway, in the attached patch
the 3 4x4 color block cases are moved to a single function.

-- 
Anssi Hannula

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