From: James Almer <jamrial@gmail.com> To: ffmpeg-devel@ffmpeg.org Subject: [FFmpeg-devel] [PATCH] avcodec/exrdec: restore applying color transfer characteristics for float16 samples Date: Thu, 13 Mar 2025 23:08:09 -0300 Message-ID: <20250314020809.14220-1-jamrial@gmail.com> (raw) Regression since 0e917389fe73c932049635d947bba076f1709589. This change also reverts commit 431805c096738da7661a0baee2b12fe9724dcc95. Signed-off-by: James Almer <jamrial@gmail.com> --- libavcodec/exr.c | 38 ++++++++++++++++++++++++++++++++++++-- 1 file changed, 36 insertions(+), 2 deletions(-) diff --git a/libavcodec/exr.c b/libavcodec/exr.c index 4482f104d0..107281e115 100644 --- a/libavcodec/exr.c +++ b/libavcodec/exr.c @@ -42,6 +42,7 @@ #include "libavutil/avstring.h" #include "libavutil/mem.h" #include "libavutil/opt.h" +#include "libavutil/float2half.h" #include "libavutil/half2float.h" #include "avcodec.h" @@ -193,7 +194,10 @@ typedef struct EXRContext { uint8_t *offset_table; + uint16_t gamma_table[65536]; + Half2FloatTables h2f_tables; + Float2HalfTables f2h_tables; } EXRContext; static int zip_uncompress(const EXRContext *s, const uint8_t *src, int compressed_size, @@ -1401,8 +1405,13 @@ static int decode_block(AVCodecContext *avctx, void *tdata, } } else if (s->pixel_type == EXR_HALF) { // 16-bit - for (int x = 0; x < xsize; x++, ptr_x += step) - AV_WN16A(ptr_x, bytestream_get_le16(&src)); + if (trc_func && (!c || (c < 3 && s->desc->flags & AV_PIX_FMT_FLAG_PLANAR))) { + for (int x = 0; x < xsize; x++, ptr_x += step) + AV_WN16A(ptr_x, s->gamma_table[bytestream_get_le16(&src)]); + } else { + for (int x = 0; x < xsize; x++, ptr_x += step) + AV_WN16A(ptr_x, bytestream_get_le16(&src)); + } } // Zero out the end if xmax+1 is not w @@ -2212,8 +2221,13 @@ static int decode_frame(AVCodecContext *avctx, AVFrame *picture, static av_cold int decode_init(AVCodecContext *avctx) { EXRContext *s = avctx->priv_data; + uint32_t i; + union av_intfloat32 t; + float one_gamma = 1.0f / s->gamma; + av_csp_trc_function trc_func = NULL; ff_init_half2float_tables(&s->h2f_tables); + ff_init_float2half_tables(&s->f2h_tables); s->avctx = avctx; @@ -2223,6 +2237,26 @@ static av_cold int decode_init(AVCodecContext *avctx) ff_bswapdsp_init(&s->bbdsp); #endif + trc_func = av_csp_trc_func_from_id(s->apply_trc_type); + if (trc_func) { + for (i = 0; i < 65536; ++i) { + t.i = half2float(i, &s->h2f_tables); + t.f = trc_func(t.f); + s->gamma_table[i] = float2half(av_float2int(t.f), &s->f2h_tables); + } + } else if (one_gamma != 1.0f) { + for (i = 0; i < 65536; ++i) { + t.i = half2float(i, &s->h2f_tables); + /* If negative value we reuse half value */ + if (t.f <= 0.0f) { + s->gamma_table[i] = i; + } else { + t.f = powf(t.f, one_gamma); + s->gamma_table[i] = float2half(t.i, &s->f2h_tables); + } + } + } + // allocate thread data, used for non EXR_RAW compression types s->thread_data = av_calloc(avctx->thread_count, sizeof(*s->thread_data)); if (!s->thread_data) -- 2.48.1 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
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