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Merge pull request #2152 from Varadraj75/feat/mkv-mpeg2-cc-extraction

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FEATURE: Add V_MPEG2 track support in MKV demuxer for CC extraction
This commit is contained in:
Carlos Fernandez Sanz
2026-02-28 14:02:09 -08:00
committed by GitHub
parent d80bf92820 a87ad2bec7
commit 5de265d64f
2 changed files with 29 additions and 4 deletions
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30
src/lib_ccx/matroska.c
View File

@@ -1,4 +1,4 @@
#include "lib_ccx.h"
#include "lib_ccx.h"
#include "utility.h"
#include "matroska.h"
#include "ccx_encoders_helpers.h"
@@ -691,7 +691,8 @@ void parse_simple_block(struct matroska_ctx *mkv_ctx, ULLONG frame_timestamp)
int is_avc = (track == mkv_ctx->avc_track_number);
int is_hevc = (track == mkv_ctx->hevc_track_number);
if (!is_avc && !is_hevc)
int is_mpeg2 = (track == mkv_ctx->mpeg2_track_number);
if (!is_avc && !is_hevc && !is_mpeg2)
{
// Skip everything except AVC/HEVC tracks
skip_bytes(file, len - 1); // 1 byte for track
@@ -710,6 +711,8 @@ void parse_simple_block(struct matroska_ctx *mkv_ctx, ULLONG frame_timestamp)
if (is_hevc)
process_hevc_frame_mkv(mkv_ctx, frame);
else if (is_mpeg2)
process_mpeg2_frame_mkv(mkv_ctx, frame);
else
process_avc_frame_mkv(mkv_ctx, frame);
@@ -723,6 +726,19 @@ static long bswap32(long v)
return swapped;
}
int process_mpeg2_frame_mkv(struct matroska_ctx *mkv_ctx, struct matroska_avc_frame frame)
{
struct lib_cc_decode *dec_ctx = update_decoder_list(mkv_ctx->ctx);
struct encoder_ctx *enc_ctx = update_encoder_list(mkv_ctx->ctx);
// Set timing from frame timestamp
set_current_pts(dec_ctx->timing, frame.FTS * (MPEG_CLOCK_FREQ / 1000));
set_fts(dec_ctx->timing);
// Use the existing MPEG-2 elementary stream processor (same as mp4.c and general_loop.c)
process_m2v(enc_ctx, dec_ctx, frame.data, frame.len, &mkv_ctx->dec_sub);
mkv_ctx->current_second = (int)(get_fts(dec_ctx->timing, dec_ctx->current_field) / 1000);
return 0;
}
int process_avc_frame_mkv(struct matroska_ctx *mkv_ctx, struct matroska_avc_frame frame)
{
int status = 0;
@@ -940,6 +956,8 @@ void parse_segment_track_entry(struct matroska_ctx *mkv_ctx)
mkv_ctx->avc_track_number = track_number;
else if (strcmp((const char *)codec_id_string, (const char *)hevc_codec_id) == 0)
mkv_ctx->hevc_track_number = track_number;
else if (strcmp((const char *)codec_id_string, (const char *)mpeg2_codec_id) == 0)
mkv_ctx->mpeg2_track_number = track_number;
MATROSKA_SWITCH_BREAK(code, code_len);
case MATROSKA_SEGMENT_TRACK_CODEC_PRIVATE:
// We handle DVB's private data differently
@@ -2042,6 +2060,7 @@ int matroska_loop(struct lib_ccx_ctx *ctx)
memset(&mkv_ctx->dec_sub, 0, sizeof(mkv_ctx->dec_sub));
mkv_ctx->avc_track_number = -1;
mkv_ctx->hevc_track_number = -1;
mkv_ctx->mpeg2_track_number = -1;
matroska_parse(mkv_ctx);
@@ -2055,6 +2074,7 @@ int matroska_loop(struct lib_ccx_ctx *ctx)
int sentence_count = mkv_ctx->sentence_count;
int avc_track_found = mkv_ctx->avc_track_number > -1;
int hevc_track_found = mkv_ctx->hevc_track_number > -1;
int mpeg2_track_found = mkv_ctx->mpeg2_track_number > -1;
int got_output = mkv_ctx->dec_sub.got_output;
matroska_free_all(mkv_ctx);
@@ -2068,10 +2088,12 @@ int matroska_loop(struct lib_ccx_ctx *ctx)
mprint("Found AVC track. ");
else if (hevc_track_found)
mprint("Found HEVC track. ");
else if (mpeg2_track_found)
mprint("Found MPEG2 track. ");
else
mprint("Found no AVC/HEVC track. ");
mprint("Found no AVC/HEVC/MPEG2 track. ");
if (got_output)
if (got_output || mpeg2_track_found)
return 1;
return sentence_count;
}

3
src/lib_ccx/matroska.h
View File

@@ -184,6 +184,7 @@ char *matroska_track_text_subtitle_id_extensions[] = {
char *avc_codec_id = "V_MPEG4/ISO/AVC";
char *hevc_codec_id = "V_MPEGH/ISO/HEVC";
char *mpeg2_codec_id = "V_MPEG2";
char *dvb_codec_id = "S_DVBSUB";
/* Messages */
@@ -247,6 +248,7 @@ struct matroska_ctx
struct cc_subtitle dec_sub;
int avc_track_number; // ID of AVC track. -1 if there is none
int hevc_track_number; // ID of HEVC track. -1 if there is none
int mpeg2_track_number; // ID of MPEG2 track. -1 if there is none
int sub_tracks_count;
int block_index;
int sentence_count;
@@ -278,6 +280,7 @@ void parse_segment_cluster(struct matroska_ctx *mkv_ctx);
void parse_simple_block(struct matroska_ctx *mkv_ctx, ULLONG frame_timestamp);
int process_avc_frame_mkv(struct matroska_ctx *mkv_ctx, struct matroska_avc_frame frame);
int process_hevc_frame_mkv(struct matroska_ctx *mkv_ctx, struct matroska_avc_frame frame);
int process_mpeg2_frame_mkv(struct matroska_ctx *mkv_ctx, struct matroska_avc_frame frame);
void parse_segment_track_entry(struct matroska_ctx *mkv_ctx);
void parse_private_codec_data(struct matroska_ctx *mkv_ctx, char *codec_id_string, ULLONG track_number, char *lang);
void parse_segment_tracks(struct matroska_ctx *mkv_ctx);