Fix DVB split critical bugs: per-pipeline state separation and timing sync

Author: Rahul-2k4

src/lib_ccx/general_loop.c

@@ -1182,35 +1182,42 @@ int process_non_multiprogram_general_loop(struct lib_ccx_ctx *ctx,
 
 					// Get or create pipeline for this DVB stream
 					struct ccx_subtitle_pipeline *pipe = get_or_create_pipeline(ctx, stream_pid, CCX_STREAM_TYPE_DVB_SUB, lang);
-					if (pipe && pipe->encoder && pipe->decoder)
+					if (pipe && pipe->encoder && pipe->decoder && pipe->dec_ctx)
 					{
-						// Save current decoder context and encoder context
-						void *saved_private = (*dec_ctx)->private_data;
-						struct encoder_ctx *saved_enc = *enc_ctx;
-
-						// Swap to pipeline's DVB decoder and encoder
-						(*dec_ctx)->private_data = pipe->decoder;
-						*enc_ctx = pipe->encoder;
-
-						// Sync timing from main context to pipeline encoder
-						// This ensures DVB decode has valid PTS/timing state
+						// Sync timing from main context to pipeline's decoder context
+						// The pipeline uses the main timing context for timestamp calculations
+						pipe->dec_ctx->timing = (*dec_ctx)->timing;
 						pipe->encoder->timing = (*dec_ctx)->timing;
 
-						// Decode DVB directly using pipeline's decoder and encoder
+						// Set the PTS for this DVB packet before decoding
+						// Without this, the DVB decoder will use stale timing
+						if (dvb_ptr->pts != CCX_NOPTS)
+						{
+							struct ccx_rational tb = {1, MPEG_CLOCK_FREQ};
+							LLONG pts;
+							if (dvb_ptr->tb.num != 1 || dvb_ptr->tb.den != MPEG_CLOCK_FREQ)
+							{
+								pts = change_timebase(dvb_ptr->pts, dvb_ptr->tb, tb);
+							}
+							else
+							{
+								pts = dvb_ptr->pts;
+							}
+							set_current_pts(pipe->dec_ctx->timing, pts);
+							set_fts(pipe->dec_ctx->timing);
+						}
+
+						// Decode DVB using the per-pipeline decoder context
+						// This ensures each stream has its own prev pointers
 						// Skip first 2 bytes (PES header) as done in process_data for DVB
-						struct cc_subtitle dvb_sub = {0};
-						dvbsub_decode(pipe->encoder, *dec_ctx, dvb_ptr->buffer + 2, dvb_ptr->len - 2, &dvb_sub);
+						dvbsub_decode(pipe->encoder, pipe->dec_ctx, dvb_ptr->buffer + 2, dvb_ptr->len - 2, &pipe->sub);
 
 						// Encode output if produced
-						if (dvb_sub.got_output)
+						if (pipe->sub.got_output)
 						{
-							encode_sub(pipe->encoder, &dvb_sub);
-							dvb_sub.got_output = 0;
+							encode_sub(pipe->encoder, &pipe->sub);
+							pipe->sub.got_output = 0;
 						}
-
-						// Restore original decoder/encoder context
-						(*dec_ctx)->private_data = saved_private;
-						*enc_ctx = saved_enc;
 					}
 				}
 				dvb_ptr = dvb_ptr->next_stream;

src/lib_ccx/lib_ccx.c

@@ -288,6 +288,23 @@ void dinit_libraries(struct lib_ccx_ctx **ctx)
 		if (p->timing)
 			dinit_timing_ctx(&p->timing);
 
+		// 4) Free per-pipeline decoder context
+		if (p->dec_ctx)
+		{
+			// Free prev if allocated by dvbsub_handle_display_segment
+			if (p->dec_ctx->prev)
+			{
+				freep(&p->dec_ctx->prev->private_data);
+				free(p->dec_ctx->prev);
+			}
+			// Note: private_data points to p->decoder which is already freed above
+			p->dec_ctx->private_data = NULL;
+			free(p->dec_ctx);
+		}
+
+		// 5) Free subtitle prev if allocated
+		free_subtitle(p->sub.prev);
+
 		free(p);
 		lctx->pipelines[i] = NULL;
 	}
@@ -619,6 +636,25 @@ struct ccx_subtitle_pipeline *get_or_create_pipeline(struct lib_ccx_ctx *ctx, in
 		return NULL;
 	}
 
+	// Initialize per-pipeline decoder context for DVB state management
+	// This is a minimal context - only the fields needed by dvbsub_decode
+	pipe->dec_ctx = calloc(1, sizeof(struct lib_cc_decode));
+	if (!pipe->dec_ctx)
+	{
+		mprint("Error: Failed to create decoder context for pipeline PID 0x%X\n", pid);
+		dvbsub_close_decoder(&pipe->decoder);
+		dinit_encoder(&pipe->encoder, 0);
+		free(pipe);
+		return NULL;
+	}
+	pipe->dec_ctx->private_data = pipe->decoder;
+	pipe->dec_ctx->codec = CCX_CODEC_DVB;
+	pipe->dec_ctx->prev = NULL;  // Will be allocated by dvbsub_handle_display_segment
+
+	// Initialize persistent cc_subtitle for DVB prev tracking
+	memset(&pipe->sub, 0, sizeof(struct cc_subtitle));
+	pipe->sub.prev = NULL;  // Will be allocated by dvbsub_handle_display_segment
+
 	// Register pipeline
 	ctx->pipelines[ctx->pipeline_count++] = pipe;
 

src/lib_ccx/lib_ccx.h

@@ -96,6 +96,8 @@ struct ccx_subtitle_pipeline
 	struct encoder_ctx *encoder;
 	struct ccx_common_timing_ctx *timing;
 	void *decoder; // Pointer to decoder context (e.g., ccx_decoders_dvb_context)
+	struct lib_cc_decode *dec_ctx; // Full decoder context for DVB state management
+	struct cc_subtitle sub;        // Persistent cc_subtitle for DVB prev tracking
 };
 
 struct lib_ccx_ctx