From 63c85abf201856f7a471cf701131e4083b5f1b8d Mon Sep 17 00:00:00 2001 From: "Steinar H. Gunderson" Date: Wed, 7 Nov 2018 17:38:35 +0100 Subject: [PATCH] Fix a pretty bad JPEG decoding bug; VA-API expects its quantization matrix to be in zigzag order. --- vaapi_jpeg_decoder.cpp | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/vaapi_jpeg_decoder.cpp b/vaapi_jpeg_decoder.cpp index 5143a28..1a3b64e 100644 --- a/vaapi_jpeg_decoder.cpp +++ b/vaapi_jpeg_decoder.cpp @@ -49,6 +49,18 @@ static mutex va_resources_mutex; return nullptr; \ } +// From libjpeg (although it's of course identical between implementations). +static const int jpeg_natural_order[DCTSIZE2] = { + 0, 1, 8, 16, 9, 2, 3, 10, + 17, 24, 32, 25, 18, 11, 4, 5, + 12, 19, 26, 33, 40, 48, 41, 34, + 27, 20, 13, 6, 7, 14, 21, 28, + 35, 42, 49, 56, 57, 50, 43, 36, + 29, 22, 15, 23, 30, 37, 44, 51, + 58, 59, 52, 45, 38, 31, 39, 46, + 53, 60, 61, 54, 47, 55, 62, 63, +}; + VAResources get_va_resources(unsigned width, unsigned height) { { @@ -396,7 +408,7 @@ shared_ptr decode_jpeg_vaapi(const string &filename) fprintf(stderr, "Baseline JPEG only!\n"); return nullptr; } - iq.quantiser_table[quant_tbl_idx][i] = qtbl->quantval[i]; + iq.quantiser_table[quant_tbl_idx][i] = qtbl->quantval[jpeg_natural_order[i]]; } } } -- 2.39.2