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h264: fix deadlocks on incomplete reference frame decoding. 

If decoding a second complementary field, and the first was
decoded in our thread, mark decoding of that field as complete.
If decoding fails, mark the decoded field/frame as complete.
Do not allow switching between field modes or field/frame mode
between slices within the same field/frame. Ensure that two
subsequent fields cover top/bottom (rather than top/frame,
bottom/frame or such nonsense situations).

Fixes various deadlocks when decoding samples with errors in
reference frames.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
tags/n0.11
Ronald S. Bultje 14 years ago
parent
c6ccb96bc9
commit
1e26a48fa2
1 changed files with 112 additions and 18 deletions
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  1. +112
    -18
      libavcodec/h264.c

+ 112
- 18
libavcodec/h264.c View File

@@ -2747,8 +2747,7 @@ static int field_end(H264Context *h, int in_setup)
s->mb_y = 0;

if (!in_setup && !s->dropable)
ff_thread_report_progress(&s->current_picture_ptr->f,
(16 * s->mb_height >> FIELD_PICTURE) - 1,
ff_thread_report_progress(&s->current_picture_ptr->f, INT_MAX,
s->picture_structure == PICT_BOTTOM_FIELD);

if (CONFIG_H264_VDPAU_DECODER &&
@@ -2871,9 +2870,7 @@ static int decode_slice_header(H264Context *h, H264Context *h0)
int num_ref_idx_active_override_flag;
unsigned int slice_type, tmp, i, j;
int default_ref_list_done = 0;
int last_pic_structure;

s->dropable = h->nal_ref_idc == 0;
int last_pic_structure, last_pic_dropable;

/* FIXME: 2tap qpel isn't implemented for high bit depth. */
if ((s->avctx->flags2 & CODEC_FLAG2_FAST) &&
@@ -2893,8 +2890,14 @@ static int decode_slice_header(H264Context *h, H264Context *h0)
}

h0->current_slice = 0;
if (!s0->first_field)
if (!s0->first_field) {
if (s->current_picture_ptr && !s->dropable &&
s->current_picture_ptr->owner2 == s) {
ff_thread_report_progress(&s->current_picture_ptr->f, INT_MAX,
s->picture_structure == PICT_BOTTOM_FIELD);
}
s->current_picture_ptr = NULL;
}
}

slice_type = get_ue_golomb_31(&s->gb);
@@ -3103,6 +3106,8 @@ static int decode_slice_header(H264Context *h, H264Context *h0)
h->mb_mbaff = 0;
h->mb_aff_frame = 0;
last_pic_structure = s0->picture_structure;
last_pic_dropable = s->dropable;
s->dropable = h->nal_ref_idc == 0;
if (h->sps.frame_mbs_only_flag) {
s->picture_structure = PICT_FRAME;
} else {
@@ -3115,7 +3120,17 @@ static int decode_slice_header(H264Context *h, H264Context *h0)
}
h->mb_field_decoding_flag = s->picture_structure != PICT_FRAME;

if (h0->current_slice == 0) {
if (h0->current_slice != 0) {
if (last_pic_structure != s->picture_structure ||
last_pic_dropable != s->dropable) {
av_log(h->s.avctx, AV_LOG_ERROR,
"Changing field mode (%d -> %d) between slices is not allowed\n",
last_pic_structure, s->picture_structure);
s->picture_structure = last_pic_structure;
s->dropable = last_pic_dropable;
return AVERROR_INVALIDDATA;
}
} else {
/* Shorten frame num gaps so we don't have to allocate reference
* frames just to throw them away */
if (h->frame_num != h->prev_frame_num) {
@@ -3134,6 +3149,72 @@ static int decode_slice_header(H264Context *h, H264Context *h0)
}
}

/* See if we have a decoded first field looking for a pair...
* Here, we're using that to see if we should mark previously
* decode frames as "finished".
* We have to do that before the "dummy" in-between frame allocation,
* since that can modify s->current_picture_ptr. */
if (s0->first_field) {
assert(s0->current_picture_ptr);
assert(s0->current_picture_ptr->f.data[0]);
assert(s0->current_picture_ptr->f.reference != DELAYED_PIC_REF);

/* Mark old field/frame as completed */
if (!last_pic_dropable && s0->current_picture_ptr->owner2 == s0) {
ff_thread_report_progress(&s0->current_picture_ptr->f, INT_MAX,
last_pic_structure == PICT_BOTTOM_FIELD);
}

/* figure out if we have a complementary field pair */
if (!FIELD_PICTURE || s->picture_structure == last_pic_structure) {
/* Previous field is unmatched. Don't display it, but let it
* remain for reference if marked as such. */
if (!last_pic_dropable && last_pic_structure != PICT_FRAME) {
ff_thread_report_progress(&s0->current_picture_ptr->f, INT_MAX,
last_pic_structure == PICT_TOP_FIELD);
}
} else {
if (s0->current_picture_ptr->frame_num != h->frame_num) {
/* This and previous field were reference, but had
* different frame_nums. Consider this field first in
* pair. Throw away previous field except for reference
* purposes. */
if (!last_pic_dropable && last_pic_structure != PICT_FRAME) {
ff_thread_report_progress(&s0->current_picture_ptr->f, INT_MAX,
last_pic_structure == PICT_TOP_FIELD);
}
} else {
/* Second field in complementary pair */
if (!((last_pic_structure == PICT_TOP_FIELD &&
s->picture_structure == PICT_BOTTOM_FIELD) ||
(last_pic_structure == PICT_BOTTOM_FIELD &&
s->picture_structure == PICT_TOP_FIELD))) {
av_log(s->avctx, AV_LOG_ERROR,
"Invalid field mode combination %d/%d\n",
last_pic_structure, s->picture_structure);
s->picture_structure = last_pic_structure;
s->dropable = last_pic_dropable;
return AVERROR_INVALIDDATA;
} else if (last_pic_dropable != s->dropable) {
av_log(s->avctx, AV_LOG_ERROR,
"Cannot combine reference and non-reference fields in the same frame\n");
av_log_ask_for_sample(s->avctx, NULL);
s->picture_structure = last_pic_structure;
s->dropable = last_pic_dropable;
return AVERROR_INVALIDDATA;
}

/* Take ownership of this buffer. Note that if another thread owned
* the first field of this buffer, we're not operating on that pointer,
* so the original thread is still responsible for reporting progress
* on that first field (or if that was us, we just did that above).
* By taking ownership, we assign responsibility to ourselves to
* report progress on the second field. */
s0->current_picture_ptr->owner2 = s0;
}
}
}

while (h->frame_num != h->prev_frame_num &&
h->frame_num != (h->prev_frame_num + 1) % (1 << h->sps.log2_max_frame_num)) {
Picture *prev = h->short_ref_count ? h->short_ref[0] : NULL;
@@ -3167,7 +3248,9 @@ static int decode_slice_header(H264Context *h, H264Context *h0)
}
}

/* See if we have a decoded first field looking for a pair... */
/* See if we have a decoded first field looking for a pair...
* We're using that to see whether to continue decoding in that
* frame, or to allocate a new one. */
if (s0->first_field) {
assert(s0->current_picture_ptr);
assert(s0->current_picture_ptr->f.data[0]);
@@ -3180,12 +3263,10 @@ static int decode_slice_header(H264Context *h, H264Context *h0)
s0->current_picture_ptr = NULL;
s0->first_field = FIELD_PICTURE;
} else {
if (h->nal_ref_idc &&
s0->current_picture_ptr->f.reference &&
s0->current_picture_ptr->frame_num != h->frame_num) {
/* This and the previous field were reference, but had
* different frame_nums. Consider this field first in pair.
* Throw away previous one except for reference purposes. */
if (s0->current_picture_ptr->frame_num != h->frame_num) {
/* This and the previous field had different frame_nums.
* Consider this field first in pair. Throw away previous
* one except for reference purposes. */
s0->first_field = 1;
s0->current_picture_ptr = NULL;
} else {
@@ -4129,8 +4210,10 @@ static int decode_nal_units(H264Context *h, const uint8_t *buf, int buf_size)

ptr = ff_h264_decode_nal(hx, buf + buf_index, &dst_length,
&consumed, next_avc - buf_index);
if (ptr == NULL || dst_length < 0)
return -1;
if (ptr == NULL || dst_length < 0) {
buf_index = -1;
goto end;
}
i = buf_index + consumed;
if ((s->workaround_bugs & FF_BUG_AUTODETECT) && i + 3 < next_avc &&
buf[i] == 0x00 && buf[i + 1] == 0x00 &&
@@ -4187,7 +4270,8 @@ again:
if (h->nal_unit_type != NAL_IDR_SLICE) {
av_log(h->s.avctx, AV_LOG_ERROR,
"Invalid mix of idr and non-idr slices");
return -1;
buf_index = -1;
goto end;
}
idr(h); // FIXME ensure we don't lose some frames if there is reordering
case NAL_SLICE:
@@ -4311,7 +4395,8 @@ again:
av_log(avctx, AV_LOG_ERROR,
"Unsupported bit depth: %d\n",
h->sps.bit_depth_luma);
return -1;
buf_index = -1;
goto end;
}
}
break;
@@ -4352,6 +4437,15 @@ again:
}
if (context_count)
execute_decode_slices(h, context_count);

end:
/* clean up */
if (s->current_picture_ptr && s->current_picture_ptr->owner2 == s &&
!s->dropable) {
ff_thread_report_progress(&s->current_picture_ptr->f, INT_MAX,
s->picture_structure == PICT_BOTTOM_FIELD);
}

return buf_index;
}



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