size_t mpeg_bitstream_parse(mpeg_bitstream_t* packet, caption_frame_t* frame, const uint8_t* data, size_t size, unsigned stream_type, double dts, double cts)
{
if (MAX_NALU_SIZE <= packet->size) {
packet->status = LIBCAPTION_ERROR;
// fprintf(stderr, "LIBCAPTION_ERROR\n");
return 0;
}
// consume upto MAX_NALU_SIZE bytes
if (MAX_NALU_SIZE <= packet->size + size) {
size = MAX_NALU_SIZE - packet->size;
}
sei_t sei;
size_t header_size, scpos;
packet->status = LIBCAPTION_OK;
memcpy(&packet->data[packet->size], data, size);
packet->size += size;
while (packet->status == LIBCAPTION_OK && 0 < (scpos = find_start_code(&packet->data[0], packet->size))) {
switch (mpeg_bitstream_packet_type(packet, stream_type)) {
default:
break;
case H262_SEI_PACKET:
header_size = 4;
if (STREAM_TYPE_H262 == stream_type && scpos > header_size) {
cea708_t* cea708 = _mpeg_bitstream_cea708_emplace_back(packet, dts + cts);
packet->status = libcaption_status_update(packet->status, cea708_parse_h262(&packet->data[header_size], scpos - header_size, cea708));
_mpeg_bitstream_cea708_sort_flush(packet, frame, dts);
}
break;
case H264_SEI_PACKET:
case H265_SEI_PACKET:
header_size = STREAM_TYPE_H264 == stream_type ? 4 : STREAM_TYPE_H265 == stream_type ? 5 : 0;
if (header_size && scpos > header_size) {
packet->status = libcaption_status_update(packet->status, sei_parse(&sei, &packet->data[header_size], scpos - header_size, dts + cts));
for (sei_message_t* msg = sei_message_head(&sei); msg; msg = sei_message_next(msg)) {
if (sei_type_user_data_registered_itu_t_t35 == sei_message_type(msg)) {
cea708_t* cea708 = _mpeg_bitstream_cea708_emplace_back(packet, dts + cts);
packet->status = libcaption_status_update(packet->status, cea708_parse_h264(sei_message_data(msg), sei_message_size(msg), cea708));
_mpeg_bitstream_cea708_sort_flush(packet, frame, dts);
}
}
sei_free(&sei);
}
break;
}
packet->size -= scpos;
memmove(&packet->data[0], &packet->data[scpos], packet->size);
}
return size;
}
void sei_cat(sei_t* to, sei_t* from, int itu_t_t35)
{
if (!to || !from) {
return;
}
sei_message_t* msg = NULL;
for (msg = sei_message_head(from); msg; msg = sei_message_next(msg)) {
if (itu_t_t35 || sei_type_user_data_registered_itu_t_t35 != msg->type) {
sei_message_append(to, sei_message_copy(msg));
}
}
}
size_t sei_render_size (sei_t* sei)
{
size_t size = 2; // nalu_type + stop bit
sei_message_t* msg;
for (msg = sei_message_head (sei) ; msg ; msg = sei_message_next (msg)) {
size += 1 + (msg->type / 255);
size += 1 + (msg->size / 255);
size += 1 + (msg->size * 4/3);
}
return size;
}
// we can safely assume sei_render_size() bytes have been allocated for data
size_t sei_render(sei_t* sei, uint8_t* data)
{
if (!sei || !sei->head) {
return 0;
}
size_t escaped_size, size = 2; // nalu_type + stop bit
sei_message_t* msg;
(*data) = 6;
++data;
for (msg = sei_message_head(sei); msg; msg = sei_message_next(msg)) {
int payloadType = sei_message_type(msg);
int payloadSize = (int)sei_message_size(msg);
uint8_t* payloadData = sei_message_data(msg);
while (255 <= payloadType) {
(*data) = 255;
++data;
++size;
payloadType -= 255;
}
(*data) = payloadType;
++data;
++size;
while (255 <= payloadSize) {
(*data) = 255;
++data;
++size;
payloadSize -= 255;
}
(*data) = payloadSize;
++data;
++size;
if (0 >= (escaped_size = _copy_from_rbsp(data, payloadData, payloadSize))) {
return 0;
}
data += escaped_size;
size += escaped_size;
}
// write stop bit and return
(*data) = 0x80;
return size;
}
libcaption_stauts_t sei_to_caption_frame(sei_t* sei, caption_frame_t* frame)
{
cea708_t cea708;
sei_message_t* msg;
libcaption_stauts_t status = LIBCAPTION_OK;
cea708_init(&cea708, frame->timestamp);
for (msg = sei_message_head(sei); msg; msg = sei_message_next(msg)) {
if (sei_type_user_data_registered_itu_t_t35 == sei_message_type(msg)) {
cea708_parse_h264(sei_message_data(msg), sei_message_size(msg), &cea708);
status = libcaption_status_update(status, cea708_to_caption_frame(frame, &cea708));
}
}
if (LIBCAPTION_READY == status) {
frame->timestamp = sei->timestamp;
}
return status;
}
