From 5080802f42c4a3ba5fad87eb149c4e7192744634 Mon Sep 17 00:00:00 2001
From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Date: Mon, 24 Feb 2025 19:30:27 +0100
Subject: [PATCH 22/30] avcodec/h26[134]dec: Always report the buffer to be
 completely consumed

It is pointless to try to report the true number because
decode_simple_internal() always treats the buffer as
completely consumed for video codecs anyway.
(Apart from that: The h263dec code would report to only
have consumed the header data in case decoding is aborted
due to skip_frame which makes no sense.)

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
---
 libavcodec/h261dec.c | 16 +---------------
 libavcodec/h263dec.c | 31 ++++---------------------------
 libavcodec/h264dec.c | 15 +--------------
 3 files changed, 6 insertions(+), 56 deletions(-)

diff --git a/libavcodec/h261dec.c b/libavcodec/h261dec.c
index 116f1d43b2..8a2c4d35b4 100644
--- a/libavcodec/h261dec.c
+++ b/libavcodec/h261dec.c
@@ -536,20 +536,6 @@ static int h261_decode_gob(H261DecContext *h)
     return -1;
 }
 
-/**
- * returns the number of bytes consumed for building the current frame
- */
-static int get_consumed_bytes(MpegEncContext *s, int buf_size)
-{
-    int pos = get_bits_count(&s->gb) >> 3;
-    if (pos == 0)
-        pos = 1;      // avoid infinite loops (i doubt that is needed but ...)
-    if (pos + 10 > buf_size)
-        pos = buf_size;               // oops ;)
-
-    return pos;
-}
-
 static int h261_decode_frame(AVCodecContext *avctx, AVFrame *pict,
                              int *got_frame, AVPacket *avpkt)
 {
@@ -615,7 +601,7 @@ static int h261_decode_frame(AVCodecContext *avctx, AVFrame *pict,
 
     *got_frame = 1;
 
-    return get_consumed_bytes(s, buf_size);
+    return buf_size;
 }
 
 const FFCodec ff_h261_decoder = {
diff --git a/libavcodec/h263dec.c b/libavcodec/h263dec.c
index 452641e408..fa1146f025 100644
--- a/libavcodec/h263dec.c
+++ b/libavcodec/h263dec.c
@@ -170,29 +170,6 @@ av_cold int ff_h263_decode_init(AVCodecContext *avctx)
     return 0;
 }
 
-/**
- * Return the number of bytes consumed for building the current frame.
- */
-static int get_consumed_bytes(MpegEncContext *s, int buf_size)
-{
-    int pos = (get_bits_count(&s->gb) + 7) >> 3;
-
-    if (s->divx_packed || s->avctx->hwaccel) {
-        /* We would have to scan through the whole buf to handle the weird
-         * reordering ... */
-        return buf_size;
-    } else {
-        // avoid infinite loops (maybe not needed...)
-        if (pos == 0)
-            pos = 1;
-        // oops ;)
-        if (pos + 10 > buf_size)
-            pos = buf_size;
-
-        return pos;
-    }
-}
-
 static int decode_slice(MpegEncContext *s)
 {
     const int part_mask = s->partitioned_frame
@@ -523,7 +500,7 @@ retry:
         }
     }
     if (ret == FRAME_SKIPPED)
-        return get_consumed_bytes(s, buf_size);
+        return buf_size;
 
     /* skip if the header was thrashed */
     if (ret < 0) {
@@ -587,13 +564,13 @@ retry:
     /* skip B-frames if we don't have reference frames */
     if (!s->last_pic.ptr &&
         (s->pict_type == AV_PICTURE_TYPE_B || s->droppable))
-        return get_consumed_bytes(s, buf_size);
+        return buf_size;
     if ((avctx->skip_frame >= AVDISCARD_NONREF &&
          s->pict_type == AV_PICTURE_TYPE_B)    ||
         (avctx->skip_frame >= AVDISCARD_NONKEY &&
          s->pict_type != AV_PICTURE_TYPE_I)    ||
         avctx->skip_frame >= AVDISCARD_ALL)
-        return get_consumed_bytes(s, buf_size);
+        return buf_size;
 
     if ((ret = ff_mpv_frame_start(s, avctx)) < 0)
         return ret;
@@ -702,7 +679,7 @@ frame_end:
     if (slice_ret < 0 && (avctx->err_recognition & AV_EF_EXPLODE))
         return slice_ret;
     else
-        return get_consumed_bytes(s, buf_size);
+        return buf_size;
 }
 
 static const AVCodecHWConfigInternal *const h263_hw_config_list[] = {
diff --git a/libavcodec/h264dec.c b/libavcodec/h264dec.c
index 45ebe2656d..fd401027d6 100644
--- a/libavcodec/h264dec.c
+++ b/libavcodec/h264dec.c
@@ -827,19 +827,6 @@ end:
     return (ret < 0) ? ret : buf_size;
 }
 
-/**
- * Return the number of bytes consumed for building the current frame.
- */
-static int get_consumed_bytes(int pos, int buf_size)
-{
-    if (pos == 0)
-        pos = 1;        // avoid infinite loops (I doubt that is needed but...)
-    if (pos + 10 > buf_size)
-        pos = buf_size; // oops ;)
-
-    return pos;
-}
-
 static int h264_export_enc_params(AVFrame *f, const H264Picture *p)
 {
     AVVideoEncParams *par;
@@ -1100,7 +1087,7 @@ static int h264_decode_frame(AVCodecContext *avctx, AVFrame *pict,
 
     ff_h264_unref_picture(&h->last_pic_for_ec);
 
-    return get_consumed_bytes(buf_index, buf_size);
+    return buf_size;
 }
 
 #define OFFSET(x) offsetof(H264Context, x)
-- 
2.45.2