/* * CEA-708 Closed Captioning FIFO * Copyright (c) 2023 LTN Global Communications * * Author: Devin Heitmueller <dheitmueller@ltnglobal.com> * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "ccfifo.h"#include "libavutil/fifo.h" #define MAX_CC_ELEMENTS 128 struct cc_lookup {    int num;    int den;    int cc_count;    int num_608;}; const static struct cc_lookup cc_lookup_vals[] = {    { 15, 1, 40, 4 },    { 24, 1, 25, 3 },    { 24000, 1001, 25, 3 },    { 30, 1, 20, 2 },    { 30000, 1001, 20, 2},    { 60, 1, 10, 1 },    { 60000, 1001, 10, 1},}; void ff_ccfifo_uninit(CCFifo *ccf){    av_fifo_freep2(&ccf->cc_608_fifo);    av_fifo_freep2(&ccf->cc_708_fifo);    memset(ccf, 0, sizeof(*ccf));} int ff_ccfifo_init(CCFifo *ccf, AVRational framerate, void *log_ctx){    int i;     memset(ccf, 0, sizeof(*ccf));    ccf->log_ctx = log_ctx;    ccf->framerate = framerate;     if (!(ccf->cc_708_fifo = av_fifo_alloc2(MAX_CC_ELEMENTS, CC_BYTES_PER_ENTRY, 0)))        goto error;     if (!(ccf->cc_608_fifo = av_fifo_alloc2(MAX_CC_ELEMENTS, CC_BYTES_PER_ENTRY, 0)))        goto error;     /* Based on the target FPS, figure out the expected cc_count and number of       608 tuples per packet.  See ANSI/CTA-708-E Sec 4.3.6.1. */    for (i = 0; i < FF_ARRAY_ELEMS(cc_lookup_vals); i++) {        if (framerate.num == cc_lookup_vals[i].num &&            framerate.den == cc_lookup_vals[i].den) {            ccf->expected_cc_count = cc_lookup_vals[i].cc_count;            ccf->expected_608 = cc_lookup_vals[i].num_608;            break;        }    }     if (ccf->expected_608 == 0) {        /* We didn't find an output frame we support.  We'll let the call succeed           and the FIFO to be allocated, but the extract/inject functions will simply           leave everything the way it is */        ccf->passthrough = 1;    }     return 0; error:    ff_ccfifo_uninit(ccf);    return AVERROR(ENOMEM);} int ff_ccfifo_injectbytes(CCFifo *ccf, uint8_t *cc_data, size_t len){    int cc_608_tuples = 0;    int cc_708_tuples = 0;    int cc_filled = 0;     if (ccf->passthrough) {        return 0;    }     if (len < ff_ccfifo_getoutputsize(ccf)) {        return AVERROR(EINVAL);    }     /* Insert any available data from the 608 FIFO */    if (ccf->expected_608 <= av_fifo_can_read(ccf->cc_608_fifo))        cc_608_tuples = ccf->expected_608;    else        cc_608_tuples = av_fifo_can_read(ccf->cc_608_fifo);    av_fifo_read(ccf->cc_608_fifo, cc_data, cc_608_tuples);    cc_filled += cc_608_tuples;     /* Insert any available data from the 708 FIFO */    if ((ccf->expected_cc_count - cc_filled) <= av_fifo_can_read(ccf->cc_708_fifo))        cc_708_tuples = ccf->expected_cc_count - cc_filled;    else        cc_708_tuples = av_fifo_can_read(ccf->cc_708_fifo);    av_fifo_read(ccf->cc_708_fifo, &cc_data[cc_filled * CC_BYTES_PER_ENTRY], cc_708_tuples);    cc_filled += cc_708_tuples;     /* Insert 708 padding into any remaining fields */    while (cc_filled < ccf->expected_cc_count) {        cc_data[cc_filled * CC_BYTES_PER_ENTRY]     = 0xfa;        cc_data[cc_filled * CC_BYTES_PER_ENTRY + 1] = 0x00;        cc_data[cc_filled * CC_BYTES_PER_ENTRY + 2] = 0x00;        cc_filled++;    }     return 0;} int ff_ccfifo_inject(CCFifo *ccf, AVFrame *frame){    AVFrameSideData *sd;    int ret;     if (ccf->passthrough == 1 || ccf->cc_detected == 0)        return 0;     sd = av_frame_new_side_data(frame, AV_FRAME_DATA_A53_CC,                                ff_ccfifo_getoutputsize(ccf));    if (sd) {        ret = ff_ccfifo_injectbytes(ccf, sd->data, sd->size);        if (ret < 0) {            av_frame_remove_side_data(frame, AV_FRAME_DATA_A53_CC);            return ret;        }    }     return 0;} int ff_ccfifo_extractbytes(CCFifo *ccf, uint8_t *cc_bytes, size_t len){    int cc_count = len / CC_BYTES_PER_ENTRY;     if (ccf->passthrough == 1) {        av_log_once(ccf->log_ctx, AV_LOG_WARNING, AV_LOG_DEBUG, &ccf->passthrough_warning,                    "cc_fifo cannot transcode captions fps=%d/%d\n",                    ccf->framerate.num, ccf->framerate.den);        return 0;    }     ccf->cc_detected = 1;     for (int i = 0; i < cc_count; i++) {        /* See ANSI/CTA-708-E Sec 4.3, Table 3 */        uint8_t cc_valid = (cc_bytes[CC_BYTES_PER_ENTRY*i] & 0x04) >> 2;        uint8_t cc_type = cc_bytes[CC_BYTES_PER_ENTRY*i] & 0x03;        if (cc_type == 0x00 || cc_type == 0x01) {            av_fifo_write(ccf->cc_608_fifo, &cc_bytes[CC_BYTES_PER_ENTRY*i], 1);        } else if (cc_valid && (cc_type == 0x02 || cc_type == 0x03)) {            av_fifo_write(ccf->cc_708_fifo, &cc_bytes[CC_BYTES_PER_ENTRY*i], 1);        }    }    return 0;} /* Read the A53 side data, discard padding, and put 608/708 into   queues so we can ensure they get into the output frames at   the correct rate... */int ff_ccfifo_extract(CCFifo *ccf, AVFrame *frame){    AVFrameSideData *side_data = av_frame_get_side_data(frame, AV_FRAME_DATA_A53_CC);    if (side_data) {        ff_ccfifo_extractbytes(ccf, side_data->data, side_data->size);         /* Remove the side data, as we will re-create it on the           output as needed */        if (!ccf->passthrough)            av_frame_remove_side_data(frame, AV_FRAME_DATA_A53_CC);    }    return 0;}