Skip to content

[IMPROVEMENT] Document why store_hdcc overwrites the slot #2392

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
cfsmp3 merged 1 commit into from
Oct 18, 2026
Merged

[IMPROVEMENT] Document why store_hdcc overwrites the slot #2392

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
7 changes: 3 additions & 4 deletions src/lib_ccx/sequencing.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,6 @@ void init_hdcc(struct lib_cc_decode *ctx)
// Buffer caption blocks for later sorting/flushing.
void store_hdcc(struct encoder_ctx *enc_ctx, struct lib_cc_decode *dec_ctx, unsigned char *cc_data, int cc_count, int sequence_number, LLONG current_fts_now, struct cc_subtitle *sub)
{
// stream_mode = dec_ctx->demux_ctx->get_stream_mode(dec_ctx->demux_ctx);
// Uninitialized?
if (dec_ctx->anchor_seq_number < 0)
{
Expand Down Expand Up @@ -54,9 +53,6 @@ void store_hdcc(struct encoder_ctx *enc_ctx, struct lib_cc_decode *dec_ctx, unsi
{
if (cc_data)
{
// Changed by CFS to concat, i.e. don't assume there's no data already for this seq_index.
// Needed at least for MP4 samples. // TODO: make sure we don't overflow
// if (stream_mode!=CCX_SM_MP4) // CFS: Very ugly hack, but looks like overwriting is needed for at least some ES
if (dec_ctx->cc_data_count[seq_index] > 0)
{
// Flush buffered cc blocks before storing new ones if fts has changed
Expand All @@ -66,6 +62,9 @@ void store_hdcc(struct encoder_ctx *enc_ctx, struct lib_cc_decode *dec_ctx, unsi
}
}
dec_ctx->cc_fts[seq_index] = current_fts_now; // CFS: Maybe do even if there's no data?
// Overwrite, don't append: a picture can carry the same 608 data
// twice, e.g. as SCTE-20 followed by GA94 user data. Appending
// would duplicate every caption character.
dec_ctx->cc_data_count[seq_index] = 0;
memcpy(dec_ctx->cc_data_pkts[seq_index] + dec_ctx->cc_data_count[seq_index] * 3, cc_data, cc_count * 3 + 1);
}
Expand Down
Loading