Sorry, but I've never modified those values myself and I don't know how they work. I think you'll have to read the source code for the JPEG encoder to find out.
- Richard On Mon, May 18, 2020 at 1:37 PM Виктор Мулин <[email protected]> wrote: > Thanks for the answer. > intra_matrix and inter_matrix are of type uint16_t, and tables from > jpegtables.c are of type uint8_t. What to do? Make a cast of uint8_t * to > uint16_t * or define a new array of type uint16_t by filling it with values > from standard tables? > Will these tables be added to the output file automatically after I > specify array references in the AVCodecContext structure? > > пн, 18 мая 2020 г. в 19:54, Richard Hussong <[email protected]>: > >> >> >> On Mon, May 18, 2020 at 7:38 AM Виктор Мулин <[email protected]> wrote: >> >>> Hello! When using the mjpeg codec to convert an image from bmp to jpg >>> format, a picture with one quantization table is created. I need two >>> standard tables described in the jpeg iso / iec 10918-1 T.81 standard in >>> Appendix K.1 and K.2 to be added to the output image file. I also found >>> them in the ffmpeg source codes (jpegtables.c -> std_luminance_quant_tbl >>> and jpegtables.c -> std_chrominance_quant_tbl [url: >>> https://ffmpeg.org/doxygen/trunk/jpegtables_8c_source.html]. I looked >>> through the mailing list archive and found old solutions ( >>> https://ffmpeg.org/pipermail/libav-user/2015-July/008318.html), but now >>> the av_codec_set_chroma_intra_matrix () function is declared depricated. >>> How do I get what I want? How to set intra_matrix, chroma_intra_matrix and >>> inter_matrix (in the description they are almost the same)? >>> >> >> The intra_matrix and inter_matrix can now be set directly in the >> AVCodecContext structure. See >> https://ffmpeg.org/doxygen/trunk/structAVCodecContext.html, and search >> for "intra_matrix" and "inter_matrix". >> >> P.S .: Sorry, I don't speak English well. I use google translator. >>> >> >> Don't worry - what you wrote is clear enough. >> >>> _______________________________________________ >>> Libav-user mailing list >>> [email protected] >>> https://ffmpeg.org/mailman/listinfo/libav-user >>> >>> To unsubscribe, visit link above, or email >>> [email protected] with subject "unsubscribe". >> >> _______________________________________________ >> Libav-user mailing list >> [email protected] >> https://ffmpeg.org/mailman/listinfo/libav-user >> >> To unsubscribe, visit link above, or email >> [email protected] with subject "unsubscribe". > > _______________________________________________ > Libav-user mailing list > [email protected] > https://ffmpeg.org/mailman/listinfo/libav-user > > To unsubscribe, visit link above, or email > [email protected] with subject "unsubscribe".
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