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ppsspp/ext/ffmpeg/libavcodec/h264_parser.c
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Henrik RydgårdandClaude Opus 5.5 d0e3141f43 FFmpeg: Vendor what PPSSPP uses into ext/ffmpeg, drop the submodule 
The ffmpeg submodule held prebuilt libraries for every platform next to the
sources (about 1.5 GB checked out), and nothing uses those any more. Only the
needed sources are copied in, from the submodule's commit, along with every
header and template they include. The path is new, so checking out commits on
either side of this works.

It's also cut down to what PPSSPP uses: the H.264, AAC, MP3, ATRAC3 and ATRAC3+
decoders, the H.264 parser, the demuxers as before, and the FFV1 encoder, AVI
muxer and file protocol for AVI dumping. config.h takes its CONFIG_ values from
FFmpeg 3.0.2's own configure run with just those enabled. The raw H.264 demuxer
stays even though nothing opens raw H.264: probing PSMF data uses it to identify
the video stream's codec, which otherwise comes out as none.

On top of that:
- The files nothing links (configure would build them, but they're never pulled
  out of the static library, going by the GCC link map) are left out: mostly
  libavutil's crypto and hashing and the alternative DCT/IDCT/FFT versions.
- libswresample isn't built, now that nothing uses it.
- The H.264 decoder only does 8-bit video, which is all the PSP has. The SPS
  parser rejects any other bit depth, and the DSP files no longer build their 9-
  to 16-bit variants, which the linker kept because the init functions pick one
  by bit depth at run time.

That's 160 files to compile instead of 277, and 391 of FFmpeg's vendored, about
5.8 MB. The README in ext/ffmpeg has what was done, the PPSSPP patches in the
copy, how to add a component, and the tradeoffs.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
2026-10-25 22:27:54 +01:00

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/*
* H.26L/H.264/AVC/JVT/14496-10/... parser
* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* H.264 / AVC / MPEG4 part10 parser.
* @author Michael Niedermayer <michaelni@gmx.at>
*/
#define UNCHECKED_BITSTREAM_READER 1
#include "libavutil/attributes.h"
#include "parser.h"
#include "h264data.h"
#include "golomb.h"
#include "internal.h"
#include "mpegutils.h"
typedef struct H264ParseContext {
H264Context h;
ParseContext pc;
int got_first;
} H264ParseContext;
static int h264_find_frame_end(H264ParseContext *p, const uint8_t *buf,
int buf_size)
{
H264Context *h = &p->h;
int i, j;
uint32_t state;
ParseContext *pc = &p->pc;
int next_avc= h->is_avc ? 0 : buf_size;
// mb_addr= pc->mb_addr - 1;
state = pc->state;
if (state > 13)
state = 7;
if (h->is_avc && !h->nal_length_size)
av_log(h->avctx, AV_LOG_ERROR, "AVC-parser: nal length size invalid\n");
for (i = 0; i < buf_size; i++) {
if (i >= next_avc) {
int nalsize = 0;
i = next_avc;
for (j = 0; j < h->nal_length_size; j++)
nalsize = (nalsize << 8) | buf[i++];
if (nalsize <= 0 || nalsize > buf_size - i) {
av_log(h->avctx, AV_LOG_ERROR, "AVC-parser: nal size %d remaining %d\n", nalsize, buf_size - i);
return buf_size;
}
next_avc = i + nalsize;
state = 5;
}
if (state == 7) {
i += h->h264dsp.startcode_find_candidate(buf + i, next_avc - i);
if (i < next_avc)
state = 2;
} else if (state <= 2) {
if (buf[i] == 1)
state ^= 5; // 2->7, 1->4, 0->5
else if (buf[i])
state = 7;
else
state >>= 1; // 2->1, 1->0, 0->0
} else if (state <= 5) {
int nalu_type = buf[i] & 0x1F;
if (nalu_type == NAL_SEI || nalu_type == NAL_SPS ||
nalu_type == NAL_PPS || nalu_type == NAL_AUD) {
if (pc->frame_start_found) {
i++;
goto found;
}
} else if (nalu_type == NAL_SLICE || nalu_type == NAL_DPA ||
nalu_type == NAL_IDR_SLICE) {
state += 8;
continue;
}
state = 7;
} else {
h->parse_history[h->parse_history_count++]= buf[i];
if (h->parse_history_count>5) {
unsigned int mb, last_mb= h->parse_last_mb;
GetBitContext gb;
init_get_bits(&gb, h->parse_history, 8*h->parse_history_count);
h->parse_history_count=0;
mb= get_ue_golomb_long(&gb);
h->parse_last_mb= mb;
if (pc->frame_start_found) {
if (mb <= last_mb)
goto found;
} else
pc->frame_start_found = 1;
state = 7;
}
}
}
pc->state = state;
if (h->is_avc)
return next_avc;
return END_NOT_FOUND;
found:
pc->state = 7;
pc->frame_start_found = 0;
if (h->is_avc)
return next_avc;
return i - (state & 5) - 5 * (state > 7);
}
static int scan_mmco_reset(AVCodecParserContext *s)
{
H264ParseContext *p = s->priv_data;
H264Context *h = &p->h;
H264SliceContext *sl = &h->slice_ctx[0];
sl->slice_type_nos = s->pict_type & 3;
if (h->pps.redundant_pic_cnt_present)
get_ue_golomb(&sl->gb); // redundant_pic_count
if (ff_set_ref_count(h, sl) < 0)
return AVERROR_INVALIDDATA;
if (sl->slice_type_nos != AV_PICTURE_TYPE_I) {
int list;
for (list = 0; list < sl->list_count; list++) {
if (get_bits1(&sl->gb)) {
int index;
for (index = 0; ; index++) {
unsigned int reordering_of_pic_nums_idc = get_ue_golomb_31(&sl->gb);
if (reordering_of_pic_nums_idc < 3)
get_ue_golomb_long(&sl->gb);
else if (reordering_of_pic_nums_idc > 3) {
av_log(h->avctx, AV_LOG_ERROR,
"illegal reordering_of_pic_nums_idc %d\n",
reordering_of_pic_nums_idc);
return AVERROR_INVALIDDATA;
} else
break;
if (index >= sl->ref_count[list]) {
av_log(h->avctx, AV_LOG_ERROR,
"reference count %d overflow\n", index);
return AVERROR_INVALIDDATA;
}
}
}
}
}
if ((h->pps.weighted_pred && sl->slice_type_nos == AV_PICTURE_TYPE_P) ||
(h->pps.weighted_bipred_idc == 1 && sl->slice_type_nos == AV_PICTURE_TYPE_B))
ff_pred_weight_table(h, sl);
if (get_bits1(&sl->gb)) { // adaptive_ref_pic_marking_mode_flag
int i;
for (i = 0; i < MAX_MMCO_COUNT; i++) {
MMCOOpcode opcode = get_ue_golomb_31(&sl->gb);
if (opcode > (unsigned) MMCO_LONG) {
av_log(h->avctx, AV_LOG_ERROR,
"illegal memory management control operation %d\n",
opcode);
return AVERROR_INVALIDDATA;
}
if (opcode == MMCO_END)
return 0;
else if (opcode == MMCO_RESET)
return 1;
if (opcode == MMCO_SHORT2UNUSED || opcode == MMCO_SHORT2LONG)
get_ue_golomb_long(&sl->gb); // difference_of_pic_nums_minus1
if (opcode == MMCO_SHORT2LONG || opcode == MMCO_LONG2UNUSED ||
opcode == MMCO_LONG || opcode == MMCO_SET_MAX_LONG)
get_ue_golomb_31(&sl->gb);
}
}
return 0;
}
/**
* Parse NAL units of found picture and decode some basic information.
*
* @param s parser context.
* @param avctx codec context.
* @param buf buffer with field/frame data.
* @param buf_size size of the buffer.
*/
static inline int parse_nal_units(AVCodecParserContext *s,
AVCodecContext *avctx,
const uint8_t * const buf, int buf_size)
{
H264ParseContext *p = s->priv_data;
H264Context *h = &p->h;
H264SliceContext *sl = &h->slice_ctx[0];
int buf_index, next_avc;
unsigned int pps_id;
unsigned int slice_type;
int state = -1, got_reset = 0;
const uint8_t *ptr;
int q264 = buf_size >=4 && !memcmp("Q264", buf, 4);
int field_poc[2];
/* set some sane default values */
s->pict_type = AV_PICTURE_TYPE_I;
s->key_frame = 0;
s->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;
h->avctx = avctx;
ff_h264_reset_sei(h);
h->sei_fpa.frame_packing_arrangement_cancel_flag = -1;
if (!buf_size)
return 0;
buf_index = 0;
next_avc = h->is_avc ? 0 : buf_size;
for (;;) {
int src_length, dst_length, consumed, nalsize = 0;
if (buf_index >= next_avc) {
nalsize = get_avc_nalsize(h, buf, buf_size, &buf_index);
if (nalsize < 0)
break;
next_avc = buf_index + nalsize;
} else {
buf_index = find_start_code(buf, buf_size, buf_index, next_avc);
if (buf_index >= buf_size)
break;
if (buf_index >= next_avc)
continue;
}
src_length = next_avc - buf_index;
state = buf[buf_index];
switch (state & 0x1f) {
case NAL_SLICE:
case NAL_IDR_SLICE:
// Do not walk the whole buffer just to decode slice header
if ((state & 0x1f) == NAL_IDR_SLICE || ((state >> 5) & 0x3) == 0) {
/* IDR or disposable slice
* No need to decode many bytes because MMCOs shall not be present. */
if (src_length > 60)
src_length = 60;
} else {
/* To decode up to MMCOs */
if (src_length > 1000)
src_length = 1000;
}
break;
}
ptr = ff_h264_decode_nal(h, sl, buf + buf_index, &dst_length,
&consumed, src_length);
if (!ptr || dst_length < 0)
break;
buf_index += consumed;
init_get_bits(&h->gb, ptr, 8 * dst_length);
switch (h->nal_unit_type) {
case NAL_SPS:
ff_h264_decode_seq_parameter_set(h, 0);
break;
case NAL_PPS:
ff_h264_decode_picture_parameter_set(h, h->gb.size_in_bits);
break;
case NAL_SEI:
ff_h264_decode_sei(h);
break;
case NAL_IDR_SLICE:
s->key_frame = 1;
h->prev_frame_num = 0;
h->prev_frame_num_offset = 0;
h->prev_poc_msb =
h->prev_poc_lsb = 0;
/* fall through */
case NAL_SLICE:
init_get_bits(&sl->gb, ptr, 8 * dst_length);
get_ue_golomb_long(&sl->gb); // skip first_mb_in_slice
slice_type = get_ue_golomb_31(&sl->gb);
s->pict_type = golomb_to_pict_type[slice_type % 5];
if (h->sei_recovery_frame_cnt >= 0) {
/* key frame, since recovery_frame_cnt is set */
s->key_frame = 1;
}
pps_id = get_ue_golomb(&sl->gb);
if (pps_id >= MAX_PPS_COUNT) {
av_log(h->avctx, AV_LOG_ERROR,
"pps_id %u out of range\n", pps_id);
return -1;
}
if (!h->pps_buffers[pps_id]) {
av_log(h->avctx, AV_LOG_ERROR,
"non-existing PPS %u referenced\n", pps_id);
return -1;
}
h->pps = *h->pps_buffers[pps_id];
if (!h->sps_buffers[h->pps.sps_id]) {
av_log(h->avctx, AV_LOG_ERROR,
"non-existing SPS %u referenced\n", h->pps.sps_id);
return -1;
}
h->sps = *h->sps_buffers[h->pps.sps_id];
h->frame_num = get_bits(&sl->gb, h->sps.log2_max_frame_num);
if(h->sps.ref_frame_count <= 1 && h->pps.ref_count[0] <= 1 && s->pict_type == AV_PICTURE_TYPE_I)
s->key_frame = 1;
s->coded_width = 16 * h->sps.mb_width;
s->coded_height = 16 * h->sps.mb_height;
s->width = s->coded_width - (h->sps.crop_right + h->sps.crop_left);
s->height = s->coded_height - (h->sps.crop_top + h->sps.crop_bottom);
if (s->width <= 0 || s->height <= 0) {
s->width = s->coded_width;
s->height = s->coded_height;
}
switch (h->sps.bit_depth_luma) {
case 9:
if (CHROMA444(h)) s->format = AV_PIX_FMT_YUV444P9;
else if (CHROMA422(h)) s->format = AV_PIX_FMT_YUV422P9;
else s->format = AV_PIX_FMT_YUV420P9;
break;
case 10:
if (CHROMA444(h)) s->format = AV_PIX_FMT_YUV444P10;
else if (CHROMA422(h)) s->format = AV_PIX_FMT_YUV422P10;
else s->format = AV_PIX_FMT_YUV420P10;
break;
case 8:
if (CHROMA444(h)) s->format = AV_PIX_FMT_YUV444P;
else if (CHROMA422(h)) s->format = AV_PIX_FMT_YUV422P;
else s->format = AV_PIX_FMT_YUV420P;
break;
default:
s->format = AV_PIX_FMT_NONE;
}
avctx->profile = ff_h264_get_profile(&h->sps);
avctx->level = h->sps.level_idc;
if (h->sps.frame_mbs_only_flag) {
h->picture_structure = PICT_FRAME;
} else {
if (get_bits1(&sl->gb)) { // field_pic_flag
h->picture_structure = PICT_TOP_FIELD + get_bits1(&sl->gb); // bottom_field_flag
} else {
h->picture_structure = PICT_FRAME;
}
}
if (h->nal_unit_type == NAL_IDR_SLICE)
get_ue_golomb_long(&sl->gb); /* idr_pic_id */
if (h->sps.poc_type == 0) {
h->poc_lsb = get_bits(&sl->gb, h->sps.log2_max_poc_lsb);
if (h->pps.pic_order_present == 1 &&
h->picture_structure == PICT_FRAME)
h->delta_poc_bottom = get_se_golomb(&sl->gb);
}
if (h->sps.poc_type == 1 &&
!h->sps.delta_pic_order_always_zero_flag) {
h->delta_poc[0] = get_se_golomb(&sl->gb);
if (h->pps.pic_order_present == 1 &&
h->picture_structure == PICT_FRAME)
h->delta_poc[1] = get_se_golomb(&sl->gb);
}
/* Decode POC of this picture.
* The prev_ values needed for decoding POC of the next picture are not set here. */
field_poc[0] = field_poc[1] = INT_MAX;
ff_init_poc(h, field_poc, &s->output_picture_number);
/* Continue parsing to check if MMCO_RESET is present.
* FIXME: MMCO_RESET could appear in non-first slice.
* Maybe, we should parse all undisposable non-IDR slice of this
* picture until encountering MMCO_RESET in a slice of it. */
if (h->nal_ref_idc && h->nal_unit_type != NAL_IDR_SLICE) {
got_reset = scan_mmco_reset(s);
if (got_reset < 0)
return got_reset;
}
/* Set up the prev_ values for decoding POC of the next picture. */
h->prev_frame_num = got_reset ? 0 : h->frame_num;
h->prev_frame_num_offset = got_reset ? 0 : h->frame_num_offset;
if (h->nal_ref_idc != 0) {
if (!got_reset) {
h->prev_poc_msb = h->poc_msb;
h->prev_poc_lsb = h->poc_lsb;
} else {
h->prev_poc_msb = 0;
h->prev_poc_lsb =
h->picture_structure == PICT_BOTTOM_FIELD ? 0 : field_poc[0];
}
}
if (h->sps.pic_struct_present_flag) {
switch (h->sei_pic_struct) {
case SEI_PIC_STRUCT_TOP_FIELD:
case SEI_PIC_STRUCT_BOTTOM_FIELD:
s->repeat_pict = 0;
break;
case SEI_PIC_STRUCT_FRAME:
case SEI_PIC_STRUCT_TOP_BOTTOM:
case SEI_PIC_STRUCT_BOTTOM_TOP:
s->repeat_pict = 1;
break;
case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
s->repeat_pict = 2;
break;
case SEI_PIC_STRUCT_FRAME_DOUBLING:
s->repeat_pict = 3;
break;
case SEI_PIC_STRUCT_FRAME_TRIPLING:
s->repeat_pict = 5;
break;
default:
s->repeat_pict = h->picture_structure == PICT_FRAME ? 1 : 0;
break;
}
} else {
s->repeat_pict = h->picture_structure == PICT_FRAME ? 1 : 0;
}
if (h->picture_structure == PICT_FRAME) {
s->picture_structure = AV_PICTURE_STRUCTURE_FRAME;
if (h->sps.pic_struct_present_flag) {
switch (h->sei_pic_struct) {
case SEI_PIC_STRUCT_TOP_BOTTOM:
case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
s->field_order = AV_FIELD_TT;
break;
case SEI_PIC_STRUCT_BOTTOM_TOP:
case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
s->field_order = AV_FIELD_BB;
break;
default:
s->field_order = AV_FIELD_PROGRESSIVE;
break;
}
} else {
if (field_poc[0] < field_poc[1])
s->field_order = AV_FIELD_TT;
else if (field_poc[0] > field_poc[1])
s->field_order = AV_FIELD_BB;
else
s->field_order = AV_FIELD_PROGRESSIVE;
}
} else {
if (h->picture_structure == PICT_TOP_FIELD)
s->picture_structure = AV_PICTURE_STRUCTURE_TOP_FIELD;
else
s->picture_structure = AV_PICTURE_STRUCTURE_BOTTOM_FIELD;
s->field_order = AV_FIELD_UNKNOWN;
}
return 0; /* no need to evaluate the rest */
}
}
if (q264)
return 0;
/* didn't find a picture! */
av_log(h->avctx, AV_LOG_ERROR, "missing picture in access unit with size %d\n", buf_size);
return -1;
}
static int h264_parse(AVCodecParserContext *s,
AVCodecContext *avctx,
const uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size)
{
H264ParseContext *p = s->priv_data;
H264Context *h = &p->h;
ParseContext *pc = &p->pc;
int next;
if (!p->got_first) {
p->got_first = 1;
if (avctx->extradata_size) {
h->avctx = avctx;
// must be done like in decoder, otherwise opening the parser,
// letting it create extradata and then closing and opening again
// will cause has_b_frames to be always set.
// Note that estimate_timings_from_pts does exactly this.
if (!avctx->has_b_frames)
h->low_delay = 1;
ff_h264_decode_extradata(h, avctx->extradata, avctx->extradata_size);
}
}
if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
next = buf_size;
} else {
next = h264_find_frame_end(p, buf, buf_size);
if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
*poutbuf = NULL;
*poutbuf_size = 0;
return buf_size;
}
if (next < 0 && next != END_NOT_FOUND) {
av_assert1(pc->last_index + next >= 0);
h264_find_frame_end(p, &pc->buffer[pc->last_index + next], -next); // update state
}
}
parse_nal_units(s, avctx, buf, buf_size);
if (avctx->framerate.num)
avctx->time_base = av_inv_q(av_mul_q(avctx->framerate, (AVRational){avctx->ticks_per_frame, 1}));
if (h->sei_cpb_removal_delay >= 0) {
s->dts_sync_point = h->sei_buffering_period_present;
s->dts_ref_dts_delta = h->sei_cpb_removal_delay;
s->pts_dts_delta = h->sei_dpb_output_delay;
} else {
s->dts_sync_point = INT_MIN;
s->dts_ref_dts_delta = INT_MIN;
s->pts_dts_delta = INT_MIN;
}
if (s->flags & PARSER_FLAG_ONCE) {
s->flags &= PARSER_FLAG_COMPLETE_FRAMES;
}
*poutbuf = buf;
*poutbuf_size = buf_size;
return next;
}
static int h264_split(AVCodecContext *avctx,
const uint8_t *buf, int buf_size)
{
uint32_t state = -1;
int has_sps = 0;
int has_pps = 0;
const uint8_t *ptr = buf, *end = buf + buf_size;
int nalu_type;
while (ptr < end) {
ptr = avpriv_find_start_code(ptr, end, &state);
if ((state & 0xFFFFFF00) != 0x100)
break;
nalu_type = state & 0x1F;
if (nalu_type == NAL_SPS) {
has_sps = 1;
} else if (nalu_type == NAL_PPS)
has_pps = 1;
/* else if (nalu_type == 0x01 ||
* nalu_type == 0x02 ||
* nalu_type == 0x05) {
* }
*/
else if ((nalu_type != NAL_SEI || has_pps) &&
nalu_type != NAL_AUD && nalu_type != NAL_SPS_EXT &&
nalu_type != 0x0f) {
if (has_sps) {
while (ptr - 4 > buf && ptr[-5] == 0)
ptr--;
return ptr - 4 - buf;
}
}
}
return 0;
}
static void h264_close(AVCodecParserContext *s)
{
H264ParseContext *p = s->priv_data;
H264Context *h = &p->h;
ParseContext *pc = &p->pc;
av_freep(&pc->buffer);
ff_h264_free_context(h);
}
static av_cold int init(AVCodecParserContext *s)
{
H264ParseContext *p = s->priv_data;
H264Context *h = &p->h;
h->slice_ctx = av_mallocz(sizeof(*h->slice_ctx));
if (!h->slice_ctx)
return 0;
h->nb_slice_ctx = 1;
h->slice_context_count = 1;
ff_h264dsp_init(&h->h264dsp, 8, 1);
return 0;
}
AVCodecParser ff_h264_parser = {
.codec_ids = { AV_CODEC_ID_H264 },
.priv_data_size = sizeof(H264ParseContext),
.parser_init = init,
.parser_parse = h264_parse,
.parser_close = h264_close,
.split = h264_split,
};
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