Sorry, the information that the picture has acquired blue shades is false! вт, 19 мая 2020 г. в 11:53, Виктор Мулин <[email protected]>:
> I tried the following before opening the encoder: > codec_context-> intra_matrix = (uint16_t *) std_luminance_quant_tbl; > codec_context-> croma_intra_matrix = (uint16_t *) std_crominance_quant_tbl; > The picture has acquired a blue tint. When packet was written to a file, > DQT tables were not added to the file. > Questions remain open: > 1) How to force a codec to use two standard DQT tables (JPEG ISO / IEC > 10918-1 ITU-T recomendation T.81 Annex K.1 and K.2) > 2) How to make the codec add both DQT tables to paccket->data, then save > packet->data to a jpg file? > > пн, 18 мая 2020 г. в 23:16, Richard Hussong <[email protected]>: > >> 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". >> >> _______________________________________________ >> 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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