diff --git a/doc/APIchanges b/doc/APIchanges
index 4027d599e7..344f484a8b 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -15,6 +15,9 @@ libavutil:     2017-10-21
 
 API changes, most recent first:
 
+2021-03-xx - xxxxxxxxxx - avcodec.h
+  Deprecate AV_CODEC_FLAG_TRUNCATED, as it is redundant with parsers.
+
 2021-03-04 - xxxxxxxxxx - lavc 58.128.101 - avcodec.h
   Enable err_recognition to be set for encoders.
 
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 46d31b34ad..45929d6b05 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -310,11 +310,15 @@ typedef struct RcOverride{
  * error[?] variables will be set during encoding.
  */
 #define AV_CODEC_FLAG_PSNR            (1 << 15)
+#if FF_API_FLAG_TRUNCATED
 /**
  * Input bitstream might be truncated at a random location
  * instead of only at frame boundaries.
+ *
+ * @deprecated use codec parsers for packetizing input
  */
 #define AV_CODEC_FLAG_TRUNCATED       (1 << 16)
+#endif
 /**
  * Use interlaced DCT.
  */
diff --git a/libavcodec/decode.c b/libavcodec/decode.c
index c976795311..c00069b8d4 100644
--- a/libavcodec/decode.c
+++ b/libavcodec/decode.c
@@ -462,7 +462,11 @@ FF_ENABLE_DEPRECATION_WARNINGS
     if (!got_frame)
         av_frame_unref(frame);
 
-    if (ret >= 0 && avctx->codec->type == AVMEDIA_TYPE_VIDEO && !(avctx->flags & AV_CODEC_FLAG_TRUNCATED))
+    if (ret >= 0 && avctx->codec->type == AVMEDIA_TYPE_VIDEO
+#if FF_API_FLAG_TRUNCATED
+        && !(avctx->flags & AV_CODEC_FLAG_TRUNCATED)
+#endif
+        )
         ret = pkt->size;
 
 #if FF_API_AVCTX_TIMEBASE
diff --git a/libavcodec/h263dec.c b/libavcodec/h263dec.c
index dafa54d8d4..57d4a0d4e7 100644
--- a/libavcodec/h263dec.c
+++ b/libavcodec/h263dec.c
@@ -172,13 +172,17 @@ static int get_consumed_bytes(MpegEncContext *s, int buf_size)
         /* We would have to scan through the whole buf to handle the weird
          * reordering ... */
         return buf_size;
-    } else if (s->avctx->flags & AV_CODEC_FLAG_TRUNCATED) {
+    }
+#if FF_API_FLAG_TRUNCATED
+    else if (s->avctx->flags & AV_CODEC_FLAG_TRUNCATED) {
         pos -= s->parse_context.last_index;
         // padding is not really read so this might be -1
         if (pos < 0)
             pos = 0;
         return pos;
-    } else {
+    }
+#endif
+    else {
         // avoid infinite loops (maybe not needed...)
         if (pos == 0)
             pos = 1;
@@ -443,6 +447,7 @@ int ff_h263_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
         return 0;
     }
 
+#if FF_API_FLAG_TRUNCATED
     if (s->avctx->flags & AV_CODEC_FLAG_TRUNCATED) {
         int next;
 
@@ -462,6 +467,7 @@ int ff_h263_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
                              &buf_size) < 0)
             return buf_size;
     }
+#endif
 
 retry:
     if (s->divx_packed && s->bitstream_buffer_size) {
diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c
index 92dd6a0b24..9e1f9c4b79 100644
--- a/libavcodec/mpeg12dec.c
+++ b/libavcodec/mpeg12dec.c
@@ -1267,10 +1267,14 @@ static int mpeg_decode_postinit(AVCodecContext *avctx)
         (s1->save_progressive_seq != s->progressive_sequence && FFALIGN(s->height, 16) != FFALIGN(s->height, 32)) ||
         0) {
         if (s1->mpeg_enc_ctx_allocated) {
+#if FF_API_FLAG_TRUNCATED
             ParseContext pc = s->parse_context;
             s->parse_context.buffer = 0;
             ff_mpv_common_end(s);
             s->parse_context = pc;
+#else
+            ff_mpv_common_end(s);
+#endif
             s1->mpeg_enc_ctx_allocated = 0;
         }
 
@@ -2506,7 +2510,11 @@ static int decode_chunks(AVCodecContext *avctx, AVFrame *picture,
             if (avctx->err_recognition & AV_EF_EXPLODE && s2->er.error_count)
                 return AVERROR_INVALIDDATA;
 
-            return FFMAX(0, buf_ptr - buf - s2->parse_context.last_index);
+            return FFMAX(0, buf_ptr - buf
+#if FF_API_FLAG_TRUNCATED
+                         - s2->parse_context.last_index
+#endif
+                        );
         }
 
         input_size = buf_end - buf_ptr;
@@ -2812,6 +2820,7 @@ static int mpeg_decode_frame(AVCodecContext *avctx, void *data,
         return buf_size;
     }
 
+#if FF_API_FLAG_TRUNCATED
     if (s2->avctx->flags & AV_CODEC_FLAG_TRUNCATED) {
         int next = ff_mpeg1_find_frame_end(&s2->parse_context, buf,
                                            buf_size, NULL);
@@ -2820,6 +2829,7 @@ static int mpeg_decode_frame(AVCodecContext *avctx, void *data,
                              (const uint8_t **) &buf, &buf_size) < 0)
             return buf_size;
     }
+#endif
 
     s2->codec_tag = avpriv_toupper4(avctx->codec_tag);
     if (s->mpeg_enc_ctx_allocated == 0 && (   s2->codec_tag == AV_RL32("VCR2")
diff --git a/libavcodec/mpegvideo.c b/libavcodec/mpegvideo.c
index 988dd18a33..45f42618e2 100644
--- a/libavcodec/mpegvideo.c
+++ b/libavcodec/mpegvideo.c
@@ -944,7 +944,9 @@ av_cold int ff_mpv_common_init(MpegEncContext *s)
     if ((ret = init_context_frame(s)))
         return AVERROR(ENOMEM);
 
+#if FF_API_FLAG_TRUNCATED
     s->parse_context.state = -1;
+#endif
 
     s->context_initialized = 1;
     memset(s->thread_context, 0, sizeof(s->thread_context));
@@ -1123,8 +1125,10 @@ void ff_mpv_common_end(MpegEncContext *s)
         s->slice_context_count = 1;
     } else free_duplicate_context(s);
 
+#if FF_API_FLAG_TRUNCATED
     av_freep(&s->parse_context.buffer);
     s->parse_context.buffer_size = 0;
+#endif
 
     av_freep(&s->bitstream_buffer);
     s->allocated_bitstream_buffer_size = 0;
@@ -2320,12 +2324,14 @@ void ff_mpeg_flush(AVCodecContext *avctx){
     s->mb_x= s->mb_y= 0;
     s->closed_gop= 0;
 
+#if FF_API_FLAG_TRUNCATED
     s->parse_context.state= -1;
     s->parse_context.frame_start_found= 0;
     s->parse_context.overread= 0;
     s->parse_context.overread_index= 0;
     s->parse_context.index= 0;
     s->parse_context.last_index= 0;
+#endif
     s->bitstream_buffer_size=0;
     s->pp_time=0;
 }
diff --git a/libavcodec/mpegvideo.h b/libavcodec/mpegvideo.h
index 5a99c19656..0779a3d51a 100644
--- a/libavcodec/mpegvideo.h
+++ b/libavcodec/mpegvideo.h
@@ -359,7 +359,9 @@ typedef struct MpegEncContext {
     int mb_num_left;                 ///< number of MBs left in this video packet (for partitioned Slices only)
     int next_p_frame_damaged;        ///< set if the next p frame is damaged, to avoid showing trashed B-frames
 
+#if FF_API_FLAG_TRUNCATED
     ParseContext parse_context;
+#endif
 
     /* H.263 specific */
     int gob_index;
diff --git a/libavcodec/options_table.h b/libavcodec/options_table.h
index e12159f734..3202f68cd3 100644
--- a/libavcodec/options_table.h
+++ b/libavcodec/options_table.h
@@ -59,7 +59,9 @@ static const AVOption avcodec_options[] = {
 {"pass2", "use internal 2-pass ratecontrol in second pass mode", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG_PASS2 }, INT_MIN, INT_MAX, 0, "flags"},
 {"gray", "only decode/encode grayscale", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG_GRAY }, INT_MIN, INT_MAX, V|E|D, "flags"},
 {"psnr", "error[?] variables will be set during encoding", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG_PSNR }, INT_MIN, INT_MAX, V|E, "flags"},
+#if FF_API_FLAG_TRUNCATED
 {"truncated", "Input bitstream might be randomly truncated", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG_TRUNCATED }, INT_MIN, INT_MAX, V|D, "flags"},
+#endif
 {"ildct", "use interlaced DCT", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG_INTERLACED_DCT }, INT_MIN, INT_MAX, V|E, "flags"},
 {"low_delay", "force low delay", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG_LOW_DELAY }, INT_MIN, INT_MAX, V|D|E, "flags"},
 {"global_header", "place global headers in extradata instead of every keyframe", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG_GLOBAL_HEADER }, INT_MIN, INT_MAX, V|A|E, "flags"},
diff --git a/libavcodec/pthread.c b/libavcodec/pthread.c
index 572471586d..86c208e73e 100644
--- a/libavcodec/pthread.c
+++ b/libavcodec/pthread.c
@@ -46,7 +46,9 @@
 static void validate_thread_parameters(AVCodecContext *avctx)
 {
     int frame_threading_supported = (avctx->codec->capabilities & AV_CODEC_CAP_FRAME_THREADS)
+#if FF_API_FLAG_TRUNCATED
                                 && !(avctx->flags  & AV_CODEC_FLAG_TRUNCATED)
+#endif
                                 && !(avctx->flags  & AV_CODEC_FLAG_LOW_DELAY)
                                 && !(avctx->flags2 & AV_CODEC_FLAG2_CHUNKS);
     if (avctx->thread_count == 1) {
diff --git a/libavcodec/version.h b/libavcodec/version.h
index 169c763e8a..d3e813428b 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -162,5 +162,8 @@
 #ifndef FF_API_GET_FRAME_CLASS
 #define FF_API_GET_FRAME_CLASS     (LIBAVCODEC_VERSION_MAJOR < 60)
 #endif
+#ifndef FF_API_FLAG_TRUNCATED
+#define FF_API_FLAG_TRUNCATED      (LIBAVCODEC_VERSION_MAJOR < 60)
+#endif
 
 #endif /* AVCODEC_VERSION_H */
