[FFmpeg-devel] [PATCH] libopenjpeg wrapper for jpeg2k decoding

[Jai Menon]

Hi,

On Tue, Feb 3, 2009 at 5:51 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> On Tue, Feb 03, 2009 at 11:31:23AM +0530, Jai Menon wrote:
>> Hi,
>>
>> On Tue, Feb 3, 2009 at 12:58 AM, Michael Niedermayer <michaelni at gmx.at> wrote:
>> > On Mon, Feb 02, 2009 at 04:48:17PM +0530, Jai Menon wrote:
>> >> Hi,
>> >>
>> >> 2009/1/29 Michael Niedermayer <michaelni at gmx.at>:
>> >> > On Thu, Jan 29, 2009 at 11:35:31AM +0530, Jai Menon wrote:
>> >> >> Hi,
>> >> >>
>> >> >> On Thu, Jan 29, 2009 at 4:27 AM, Michael Niedermayer <michaelni at gmx.at> wrote:
>> >> >> > On Wed, Jan 28, 2009 at 02:23:46PM +0530, Jai Menon wrote:
>> >>
>> >> [...]
>> >>
>> >> > dec is written to twice with no read in between, this applies to more vars
>> >>
>> >> fixed.
>> >>
>> >> [...]
>> >>
>> >> > sec hole when width/height changes
>> >>
>> >> fixed (i think).
>> >>
>> >> i also reworked most of the code to use get/release_buffer
>> >> revised patch attached.
>> > [...]
>> >> +static int libopenjpeg_decode_frame(AVCodecContext *avctx,
>> >> +                                    void *data, int *data_size,
>> >> +                                    const uint8_t *buf, int buf_size)
>> >> +{
>> >> +    LibOpenJPEGContext *ctx = avctx->priv_data;
>> >> +    AVFrame *picture = &ctx->image, *output = data;
>> >> +    opj_dinfo_t *dec;
>> >
>> >> +    opj_cio_t *stream = NULL;
>> >
>> > written twice before read
>>
>> this and another one fixed.
>>
>> >> +    opj_image_t *image = NULL;
>> >> +    int width, height, has_alpha = 0, ret = -1;
>> >> +    int x, y, index;
>> >> +    uint8_t *img_ptr;
>> >> +    float scale;
>> >> +
>> >> +    *data_size = 0;
>> >> +
>> >> +    // Check if input is a raw jpeg2k codestream or in jp2 wrapping
>> >> +    if((AV_RB32(buf) == 12) &&
>> >> +       (AV_RB32(buf + 4) == JP2_SIG_TYPE) &&
>> >> +       (AV_RB32(buf + 8) == JP2_SIG_VALUE)) {
>> >> +         dec = opj_create_decompress(CODEC_JP2);
>> >
>> >> +    }
>> >> +    else dec = opj_create_decompress(CODEC_J2K);
>> >
>> > diego likely wont like this kind of } placement style
>>
>> changed.
>>
>> > [...]
>> >> +    scale = 255.0f / (float)((1 << image->comps[0].prec) - 1);
>> >> +    for(y = 0; y < height; y++) {
>> >> +        index = y*width;
>> >> +        img_ptr = picture->data[0] + y*picture->linesize[0];
>> >> +        for(x = 0; x < width; x++, index++) {
>> >> +            *img_ptr++ = image->comps[0].data[index] * scale;
>> >> +            if(image->numcomps > 2 && check_image_attributes(image)) {
>> >> +                *img_ptr++ = image->comps[1].data[index] * scale;
>> >> +                *img_ptr++ = image->comps[2].data[index] * scale;
>> >> +                if(has_alpha)
>> >> +                    *img_ptr++ = image->comps[3].data[index] * scale;
>> >> +            }
>> >> +        }
>> >> +    }
>> >
>> > lrintf()
>>
>> hmm...i made this generic and modified it to use integer arithmetic. i
>> think its better.
>> revised patch attached.
>>
>
> [...]
>
>> +        if(image->comps[x].prec > 8)
>> +             adjust[x] = image->comps[x].prec - 8;
>> +        else adjust[x] = 0;
>
> there should be a {} between the if/else, it doesnt add any extra lines
> but allows something to be inserted without changing the if/else lines, that
> is it means future patches would be simpler
>
> but then i realize now this could be written simpler with FFMAX()

changed.

>> +    }
>> +
>> +    for(y = 0; y < height; y++) {
>> +        index = y*width;
>> +        img_ptr = picture->data[0] + y*picture->linesize[0];
>> +        for(x = 0; x < width; x++, index++) {
>> +            *img_ptr++ = (image->comps[0].data[index] >> adjust[0]) +
>> +                         (image->comps[0].data[index] >> (adjust[0] - 1) & 1);
>
> if adjust[x] == 0 -> A >> (-1) which is undefined
>
> also this looks like (data+(1<<(adjust-1)))>>adjust

made it much simpler since i didn't see any difference in the test images.

[...]

-- 
Regards,

Jai
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