rtpdec_jpeg.h File Reference

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Functions
int	decode_frame_jpeg (struct coded_data *cdata, void *decode_data)

Detailed Description

Author

Martin Pulec pulec.nosp@m.@ces.nosp@m.net.c.nosp@m.z

Definition in file rtpdec_jpeg.h.

Function Documentation

decode_frame_jpeg()

int decode_frame_jpeg	(	struct coded_data *	cdata,
		void *	decode_data )

Definition at line 267 of file rtpdec_jpeg.c.

{
        struct decode_data_rtsp *dec_data = decode_data;
 
        struct video_frame *frame = dec_data->frame;
        // table with Q=255 must be always (re)set
        dec_data->jpeg.quantization_table_set[QUANT_TAB_T_DYN] = false;
        uint8_t q = -1;
        unsigned received_bytes = 0;
        unsigned frame_max_len = 0; // off + data_len
 
        while (cdata != NULL) {
                rtp_packet *pckt = cdata->data;
                unsigned char *pckt_data = (unsigned char *) pckt->data;
 
                uint32_t hdr = 0;
                memcpy(&hdr, pckt_data, sizeof hdr);
                const unsigned off = ntohl(hdr) & 0xFFFFFFU;
                memcpy(&q, pckt_data + 5, sizeof q);
                if (frame->tiles[0].width == 0) {
                        char *hdr_end = create_jpeg_frame(
                            frame, &pckt_data, &dec_data->jpeg.dqt_start,
                            dec_data->jpeg.not_first_run);
                        if (hdr_end == NULL) {
                                return false;
                        }
                        dec_data->offset_len =
                            (int) (hdr_end - frame->tiles[0].data);
                } else {
                        skip_jpeg_headers(&pckt_data);
                }
                // for q>=128, 1st pckt contains tables
                if (off == 0 && q >= QUANT_TAB_T_FIRST_STATIC) {
                        const unsigned char *end =
                            (unsigned char *) pckt->data + pckt->data_len;
                        parse_quant_tables(dec_data, &pckt_data, end, q);
                }
 
                const long payload_hdr_len =
                    pckt_data - (unsigned char *) pckt->data;
                const long     data_len  = pckt->data_len - payload_hdr_len;
                const unsigned frame_off = off + dec_data->offset_len;
                memcpy(frame->tiles[0].data + frame_off, pckt_data, data_len);
 
                received_bytes += data_len;
                frame_max_len = MAX(frame_max_len, off + data_len);
 
                cdata = cdata->nxt;
        }
 
        if (!dec_data->jpeg.quantization_table_set[q] &&
            q < QUANT_TAB_T_FIRST_STATIC) {
                MakeTables(q, dec_data->jpeg.quantization_tables[q][0],
                           dec_data->jpeg.quantization_tables[q][1]);
                dec_data->jpeg.quantization_table_set[q] = true;
        }
 
        if (!dec_data->jpeg.quantization_table_set[q]) {
                MSG(WARNING,
                    "Dropping frame - missing quantization tables for Q=%d!\n",
                    q);
                return false;
        }
 
        jpeg_writer_fill_dqt(dec_data->jpeg.dqt_start,
                             dec_data->jpeg.quantization_tables[q]);
 
        char *frame_end =
            frame->tiles[0].data + dec_data->offset_len + frame_max_len;
        jpeg_writer_write_eoi(&frame_end);
        frame->tiles[0].data_len = frame_end - frame->tiles[0].data;
 
        if (received_bytes != frame_max_len) {
                MSG(DEBUG, "Frame incomplete - expected %u bytes, got %u B!\n",
                    frame_max_len, received_bytes);
        }
 
        dec_data->jpeg.not_first_run = 1;
 
        return true;
}

References create_jpeg_frame(), coded_data::data, tile::data, tile::data_len, DEBUG, decode_data_rtsp::dqt_start, decode_data_rtsp::frame, frame, decode_data_rtsp::jpeg, jpeg_writer_fill_dqt(), jpeg_writer_write_eoi(), MakeTables(), MAX, MSG, decode_data_rtsp::not_first_run, coded_data::nxt, decode_data_rtsp::offset_len, parse_quant_tables(), QUANT_TAB_T_DYN, QUANT_TAB_T_FIRST_STATIC, decode_data_rtsp::quantization_table_set, decode_data_rtsp::quantization_tables, rtp_packet, skip_jpeg_headers(), video_frame::tiles, and tile::width.

Referenced by init_rtsp().

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