Re: [FFmpeg-devel] [PATCH] avcodec/tiff: add support for decoding compressed rgb floating point formats

[Andreas Rheinhardt <andreas.rheinhardt@outlook.com>]

Mark Reid:
> On Sat, Oct 1, 2022 at 7:22 AM Andreas Rheinhardt <
> andreas.rheinhardt@outlook.com> wrote:
> 
>> mindmark@gmail.com:
>>> From: Mark Reid <mindmark@gmail.com>
>>>
>>> floating point uses a slightly different predictor technique describe
>> here
>>> http://chriscox.org/TIFFTN3d1.pdf
>>>
>>> Here is a link the test files, if someone could add them to fate me
>>> https://www.dropbox.com/s/fg59h2os4gb4wug/tiff_fate_samples.zip
>>>
>>>
>>> ---
>>>  libavcodec/tiff.c                          | 66 +++++++++++++++++++++-
>>>  tests/fate/image.mak                       | 18 ++++++
>>>  tests/ref/fate/tiff-lzw-rgbaf32le          |  6 ++
>>>  tests/ref/fate/tiff-lzw-rgbf32le           |  6 ++
>>>  tests/ref/fate/tiff-uncompressed-rgbaf32le |  6 ++
>>>  tests/ref/fate/tiff-uncompressed-rgbf32le  |  6 ++
>>>  tests/ref/fate/tiff-zip-rgbaf32le          |  6 ++
>>>  tests/ref/fate/tiff-zip-rgbf32le           |  6 ++
>>>  8 files changed, 119 insertions(+), 1 deletion(-)
>>>  create mode 100644 tests/ref/fate/tiff-lzw-rgbaf32le
>>>  create mode 100644 tests/ref/fate/tiff-lzw-rgbf32le
>>>  create mode 100644 tests/ref/fate/tiff-uncompressed-rgbaf32le
>>>  create mode 100644 tests/ref/fate/tiff-uncompressed-rgbf32le
>>>  create mode 100644 tests/ref/fate/tiff-zip-rgbaf32le
>>>  create mode 100644 tests/ref/fate/tiff-zip-rgbf32le
>>>
>>> diff --git a/libavcodec/tiff.c b/libavcodec/tiff.c
>>> index 3a610ada85..c1d07f8c3e 100644
>>> --- a/libavcodec/tiff.c
>>> +++ b/libavcodec/tiff.c
>>> @@ -1913,7 +1913,7 @@ static int decode_frame(AVCodecContext *avctx,
>> AVFrame *p,
>>>      TiffContext *const s = avctx->priv_data;
>>>      unsigned off, last_off = 0;
>>>      int le, ret, plane, planes;
>>> -    int i, j, entries, stride;
>>> +    int i, j, k, entries, stride;
>>
>> Don't add another loop variable. We support "for (int k = 0;" nowadays.
>>
>>>      unsigned soff, ssize;
>>>      uint8_t *dst;
>>>      GetByteContext stripsizes;
>>> @@ -2249,6 +2249,70 @@ again:
>>>              }
>>>          }
>>>
>>> +        /* Floating point predictor
>>> +        TIFF Technical Note 3 http://chriscox.org/TIFFTN3d1.pdf */
>>> +        if (s->predictor == 3) {
>>> +            int channels = s->bppcount;
>>> +            int lane_offset;
>>> +            uint8_t *tmpbuf;
>>> +            int bpc;
>>> +
>>> +            dst   = five_planes ? five_planes : p->data[plane];
>>> +            soff  = s->bpp >> 3;
>>> +            if (s->planar) {
>>> +                soff  = FFMAX(soff / s->bppcount, 1);
>>> +                channels = 1;
>>> +            }
>>> +            ssize = s->width * soff;
>>> +            bpc = FFMAX(soff / s->bppcount, 1); /* bytes per component
>> */
>>> +            lane_offset = s->width * channels;
>>> +
>>> +            tmpbuf = (uint8_t*)av_malloc(ssize);
>>
>> unnecessary cast.
>>
>>> +            if (!tmpbuf)
>>> +                return AVERROR(ENOMEM);
>>> +
>>> +            if (s->avctx->pix_fmt == AV_PIX_FMT_RGBF32LE ||
>>> +                s->avctx->pix_fmt == AV_PIX_FMT_RGBAF32LE) {
>>> +                for (i = 0; i < decoded_height; i++) {
>>> +                    /* copy first sample byte for each channel */
>>> +                    for (j = 0; j < channels; j++)
>>> +                        tmpbuf[j] = dst[j];
>>> +
>>> +                    /* decode horizontal differences */
>>> +                    for (j = channels; j < ssize; j++)
>>> +                        tmpbuf[j] = dst[j] + tmpbuf[j-channels];
>>> +
>>> +                    /* combine shuffled bytes from their sepearate
>> lanes */
>>
>>                                                                ^
>>
>> Did you not like this comment? I can remove it, I felt the code needed
> some explanation and I don't think the comment is the best.

There is a typo: sepearate should be separate.

> The docs example code refers to these lanes as rowIncrements, which I
> thought was a confusing name too.
> 
> Each byte of every floating point value in a row of pixels is split and
> combined into separate groups.
> A group of all the sign/exponents bytes in the row and groups for each of
> the upper, mid, and lower mantissa bytes in the row.
> 
> Maybe group_size is a better name than lane_offset now that I typed that
> out.
> 
> 
>>> +                    for (j = 0; j < lane_offset; j++) {
>>> +                        for (k = 0; k < bpc; k++) {
>>> +                            dst[bpc * j + k] = tmpbuf[(bpc - k - 1) *
>> lane_offset + j];
>>> +                        }
>>> +                    }
>>> +                    dst += stride;
>>> +                }
>>> +            } else if (s->avctx->pix_fmt == AV_PIX_FMT_RGBF32BE ||
>>> +                       s->avctx->pix_fmt == AV_PIX_FMT_RGBAF32BE) {
>>> +                /* same as LE only the shuffle at the end is reversed */
>>> +                for (i = 0; i < decoded_height; i++) {
>>> +                    for (j = 0; j < channels; j++)
>>> +                        tmpbuf[j] = dst[j];
>>> +
>>> +                    for (j = channels; j < ssize; j++)
>>> +                        tmpbuf[j] = dst[j] + tmpbuf[j-channels];
>>> +
>>> +                    for (j = 0; j < lane_offset; j++) {
>>> +                        for (k = 0; k < bpc; k++) {
>>> +                            dst[bpc * j + k] = tmpbuf[k * lane_offset +
>> j];
>>> +                        }
>>> +                    }
>>> +                    dst += stride;
>>> +                }
>>> +            } else {
>>> +                av_log(s->avctx, AV_LOG_ERROR, "unsupported floating
>> point pixel format\n");
>>> +            }
>>> +            av_free(tmpbuf);
>>> +        }
>>> +
>>>          if (s->photometric == TIFF_PHOTOMETRIC_WHITE_IS_ZERO) {
>>>              int c = (s->avctx->pix_fmt == AV_PIX_FMT_PAL8 ? (1<<s->bpp)
>> - 1 : 255);
>>>              dst = p->data[plane];
>>> diff --git a/tests/fate/image.mak b/tests/fate/image.mak
>>> index 03e794dc48..971531520d 100644
>>> --- a/tests/fate/image.mak
>>> +++ b/tests/fate/image.mak
>>> @@ -501,6 +501,24 @@ fate-tiff-fax-g3: CMD = framecrc -i
>> $(TARGET_SAMPLES)/CCITT_fax/G31D.TIF
>>>  FATE_TIFF += fate-tiff-fax-g3s
>>>  fate-tiff-fax-g3s: CMD = framecrc -i
>> $(TARGET_SAMPLES)/CCITT_fax/G31DS.TIF
>>>
>>> +FATE_TIFF += fate-tiff-uncompressed-rgbf32le
>>> +fate-tiff-uncompressed-rgbf32le: CMD = framecrc -i
>> $(TARGET_SAMPLES)/tiff/uncompressed_rgbf32le.tif
>>> +
>>> +FATE_TIFF += fate-tiff-uncompressed-rgbaf32le
>>> +fate-tiff-uncompressed-rgbaf32le: CMD = framecrc -i
>> $(TARGET_SAMPLES)/tiff/uncompressed_rgbaf32le.tif
>>> +
>>> +FATE_TIFF += fate-tiff-lzw-rgbf32le
>>> +fate-tiff-lzw-rgbf32le: CMD = framecrc -i
>> $(TARGET_SAMPLES)/tiff/lzw_rgbf32le.tif
>>> +
>>> +FATE_TIFF += fate-tiff-lzw-rgbaf32le
>>> +fate-tiff-lzw-rgbaf32le: CMD = framecrc -i
>> $(TARGET_SAMPLES)/tiff/lzw_rgbaf32le.tif
>>> +
>>> +FATE_TIFF += fate-tiff-zip-rgbf32le
>>> +fate-tiff-zip-rgbf32le: CMD = framecrc -i
>> $(TARGET_SAMPLES)/tiff/zip_rgbf32le.tif
>>> +
>>> +FATE_TIFF += fate-tiff-zip-rgbaf32le
>>> +fate-tiff-zip-rgbaf32le: CMD = framecrc -i
>> $(TARGET_SAMPLES)/tiff/zip_rgbaf32le.tif
>>> +
>>>  FATE_TIFF-$(call DEMDEC, IMAGE2, TIFF) += $(FATE_TIFF)
>>
>> I already wanted to write that framecrc tests don't really work with
>> floating point formats, but then I saw that there is no real floating
>> point code in this patch. Very weird for a floating point format.
>> (Apart from that: You want to use FRAMECRC instead of DEMDEC.)
>>
>>
> yes there is no floating point calculations involved, the process should
> always be bitexact.
> 
> you mean like this right?
> FATE_TIFF-$(call FRAMECRC, IMAGE2, TIFF) += $(FATE_TIFF)

Yes.

> 
> Thanks for the quick review!
> 
>>
>>>  FATE_IMAGE_FRAMECRC += $(FATE_TIFF-yes)
>>> diff --git a/tests/ref/fate/tiff-lzw-rgbaf32le
>> b/tests/ref/fate/tiff-lzw-rgbaf32le
>>> new file mode 100644
>>> index 0000000000..c99aa02ef0
>>> --- /dev/null
>>> +++ b/tests/ref/fate/tiff-lzw-rgbaf32le
>>> @@ -0,0 +1,6 @@
>>> +#tb 0: 1/25
>>> +#media_type 0: video
>>> +#codec_id 0: rawvideo
>>> +#dimensions 0: 8x8
>>> +#sar 0: 0/1
>>> +0,          0,          0,        1,     1024, 0x877e1d5f
>>> diff --git a/tests/ref/fate/tiff-lzw-rgbf32le
>> b/tests/ref/fate/tiff-lzw-rgbf32le
>>> new file mode 100644
>>> index 0000000000..a6d3fabfda
>>> --- /dev/null
>>> +++ b/tests/ref/fate/tiff-lzw-rgbf32le
>>> @@ -0,0 +1,6 @@
>>> +#tb 0: 1/25
>>> +#media_type 0: video
>>> +#codec_id 0: rawvideo
>>> +#dimensions 0: 8x8
>>> +#sar 0: 0/1
>>> +0,          0,          0,        1,      768, 0xad26ed90
>>> diff --git a/tests/ref/fate/tiff-uncompressed-rgbaf32le
>> b/tests/ref/fate/tiff-uncompressed-rgbaf32le
>>> new file mode 100644
>>> index 0000000000..c99aa02ef0
>>> --- /dev/null
>>> +++ b/tests/ref/fate/tiff-uncompressed-rgbaf32le
>>> @@ -0,0 +1,6 @@
>>> +#tb 0: 1/25
>>> +#media_type 0: video
>>> +#codec_id 0: rawvideo
>>> +#dimensions 0: 8x8
>>> +#sar 0: 0/1
>>> +0,          0,          0,        1,     1024, 0x877e1d5f
>>> diff --git a/tests/ref/fate/tiff-uncompressed-rgbf32le
>> b/tests/ref/fate/tiff-uncompressed-rgbf32le
>>> new file mode 100644
>>> index 0000000000..a6d3fabfda
>>> --- /dev/null
>>> +++ b/tests/ref/fate/tiff-uncompressed-rgbf32le
>>> @@ -0,0 +1,6 @@
>>> +#tb 0: 1/25
>>> +#media_type 0: video
>>> +#codec_id 0: rawvideo
>>> +#dimensions 0: 8x8
>>> +#sar 0: 0/1
>>> +0,          0,          0,        1,      768, 0xad26ed90
>>> diff --git a/tests/ref/fate/tiff-zip-rgbaf32le
>> b/tests/ref/fate/tiff-zip-rgbaf32le
>>> new file mode 100644
>>> index 0000000000..c99aa02ef0
>>> --- /dev/null
>>> +++ b/tests/ref/fate/tiff-zip-rgbaf32le
>>> @@ -0,0 +1,6 @@
>>> +#tb 0: 1/25
>>> +#media_type 0: video
>>> +#codec_id 0: rawvideo
>>> +#dimensions 0: 8x8
>>> +#sar 0: 0/1
>>> +0,          0,          0,        1,     1024, 0x877e1d5f
>>> diff --git a/tests/ref/fate/tiff-zip-rgbf32le
>> b/tests/ref/fate/tiff-zip-rgbf32le
>>> new file mode 100644
>>> index 0000000000..a6d3fabfda
>>> --- /dev/null
>>> +++ b/tests/ref/fate/tiff-zip-rgbf32le
>>> @@ -0,0 +1,6 @@
>>> +#tb 0: 1/25
>>> +#media_type 0: video
>>> +#codec_id 0: rawvideo
>>> +#dimensions 0: 8x8
>>> +#sar 0: 0/1
>>> +0,          0,          0,        1,      768, 0xad26ed90
>>> --
>>> 2.31.1.windows.1
>>>

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