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gstreamer/gst/videoparsers/h264parse.c
Mark Nauwelaerts d0b942980e videoparsers: add h264parse 
Functionally equivalent to (legacy)h264parse and re-uses the latter's low
level NAL parsing, but otherwise based on GstBaseParse, and replacing
some property configuration with caps negotiation.
2011-01-28 12:50:25 +01:00

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/* GStreamer H.264 Parser
* Copyright (C) <2010> Mark Nauwelaerts <mark.nauwelaerts@collabora.co.uk>
* Copyright (C) <2010> Collabora Multimedia
* Copyright (C) <2010> Nokia Corporation
*
* Some bits C-c,C-v'ed and s/4/3 from h264parse:
* (C) 2005 Michal Benes <michal.benes@itonis.tv>
* (C) 2008 Wim Taymans <wim.taymans@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "h264parse.h"
#include <string.h>
GST_DEBUG_CATEGORY_EXTERN (h264_parse_debug);
#define GST_CAT_DEFAULT h264_parse_debug
/* simple bitstream parser, automatically skips over
* emulation_prevention_three_bytes. */
typedef struct
{
const guint8 *orig_data;
const guint8 *data;
const guint8 *end;
/* bitpos in the cache of next bit */
gint head;
/* cached bytes */
guint64 cache;
} GstNalBs;
static void
gst_nal_bs_init (GstNalBs * bs, const guint8 * data, guint size)
{
bs->orig_data = data;
bs->data = data;
bs->end = data + size;
bs->head = 0;
/* fill with something other than 0 to detect emulation prevention bytes */
bs->cache = 0xffffffff;
}
static inline void
gst_nal_bs_get_data (GstNalBs * bs, const guint8 ** data, guint * size)
{
*data = bs->orig_data;
*size = bs->end - bs->orig_data;
}
static guint32
gst_nal_bs_read (GstNalBs * bs, guint n)
{
guint32 res = 0;
gint shift;
if (n == 0)
return res;
/* fill up the cache if we need to */
while (bs->head < n) {
guint8 byte;
gboolean check_three_byte;
check_three_byte = TRUE;
next_byte:
if (bs->data >= bs->end) {
/* we're at the end, can't produce more than head number of bits */
n = bs->head;
break;
}
/* get the byte, this can be an emulation_prevention_three_byte that we need
* to ignore. */
byte = *bs->data++;
if (check_three_byte && byte == 0x03 && ((bs->cache & 0xffff) == 0)) {
/* next byte goes unconditionally to the cache, even if it's 0x03 */
check_three_byte = FALSE;
goto next_byte;
}
/* shift bytes in cache, moving the head bits of the cache left */
bs->cache = (bs->cache << 8) | byte;
bs->head += 8;
}
/* bring the required bits down and truncate */
if ((shift = bs->head - n) > 0)
res = bs->cache >> shift;
else
res = bs->cache;
/* mask out required bits */
if (n < 32)
res &= (1 << n) - 1;
bs->head = shift;
return res;
}
static gboolean
gst_nal_bs_eos (GstNalBs * bs)
{
return (bs->data >= bs->end) && (bs->head == 0);
}
/* read unsigned Exp-Golomb code */
static gint
gst_nal_bs_read_ue (GstNalBs * bs)
{
gint i = 0;
while (gst_nal_bs_read (bs, 1) == 0 && !gst_nal_bs_eos (bs) && i < 32)
i++;
return ((1 << i) - 1 + gst_nal_bs_read (bs, i));
}
/* read signed Exp-Golomb code */
static gint
gst_nal_bs_read_se (GstNalBs * bs)
{
gint i = 0;
i = gst_nal_bs_read_ue (bs);
/* (-1)^(i+1) Ceil (i / 2) */
i = (i + 1) / 2 * (i & 1 ? 1 : -1);
return i;
}
/* end parser helper */
static void
gst_h264_params_store_nal (GstH264Params * params, GstBuffer ** store, gint id,
GstNalBs * bs)
{
const guint8 *data;
GstBuffer *buf;
guint size;
g_return_if_fail (MAX_SPS_COUNT == MAX_PPS_COUNT);
if (id >= MAX_SPS_COUNT) {
GST_DEBUG_OBJECT (params->el,
"unable to store nal, id out-of-range %d", id);
return;
}
gst_nal_bs_get_data (bs, &data, &size);
buf = gst_buffer_new_and_alloc (size);
memcpy (GST_BUFFER_DATA (buf), data, size);
gst_buffer_replace (store + id, buf);
}
static GstH264ParamsSPS *
gst_h264_params_get_sps (GstH264Params * params, guint8 sps_id, gboolean set)
{
GstH264ParamsSPS *sps;
g_return_val_if_fail (params != NULL, NULL);
if (G_UNLIKELY (sps_id >= MAX_SPS_COUNT)) {
GST_WARNING_OBJECT (params->el,
"requested sps_id=%04x out of range", sps_id);
return NULL;
}
sps = &params->sps_buffers[sps_id];
if (set) {
if (sps->valid) {
params->sps = sps;
} else {
GST_WARNING_OBJECT (params->el, "invalid sps not selected");
params->sps = NULL;
sps = NULL;
}
}
return sps;
}
static GstH264ParamsPPS *
gst_h264_params_get_pps (GstH264Params * params, guint8 pps_id, gboolean set)
{
GstH264ParamsPPS *pps;
g_return_val_if_fail (params != NULL, NULL);
if (G_UNLIKELY (pps_id >= MAX_PPS_COUNT)) {
GST_WARNING_OBJECT (params->el,
"requested pps_id=%04x out of range", pps_id);
return NULL;
}
pps = &params->pps_buffers[pps_id];
if (set) {
if (pps->valid) {
params->pps = pps;
} else {
GST_WARNING_OBJECT (params->el, "invalid pps not selected");
params->pps = NULL;
pps = NULL;
}
}
return pps;
}
static gboolean
gst_h264_params_decode_sps_vui_hrd (GstH264Params * params,
GstH264ParamsSPS * sps, GstNalBs * bs)
{
gint sched_sel_idx;
sps->cpb_cnt_minus1 = gst_nal_bs_read_ue (bs);
if (sps->cpb_cnt_minus1 > 31U) {
GST_WARNING_OBJECT (params->el, "cpb_cnt_minus1 = %d out of range",
sps->cpb_cnt_minus1);
return FALSE;
}
/* bit_rate_scale */
gst_nal_bs_read (bs, 4);
/* cpb_size_scale */
gst_nal_bs_read (bs, 4);
for (sched_sel_idx = 0; sched_sel_idx <= sps->cpb_cnt_minus1; sched_sel_idx++) {
/* bit_rate_value_minus1 */
gst_nal_bs_read_ue (bs);
/* cpb_size_value_minus1 */
gst_nal_bs_read_ue (bs);
/* cbr_flag */
gst_nal_bs_read (bs, 1);
}
sps->initial_cpb_removal_delay_length_minus1 = gst_nal_bs_read (bs, 5);
sps->cpb_removal_delay_length_minus1 = gst_nal_bs_read (bs, 5);
sps->dpb_output_delay_length_minus1 = gst_nal_bs_read (bs, 5);
sps->time_offset_length_minus1 = gst_nal_bs_read (bs, 5);
return TRUE;
}
static gboolean
gst_h264_params_decode_sps_vui (GstH264Params * params, GstH264ParamsSPS * sps,
GstNalBs * bs)
{
if (G_UNLIKELY (!sps))
return FALSE;
/* aspect_ratio_info_present_flag */
if (gst_nal_bs_read (bs, 1)) {
/* aspect_ratio_idc */
if (gst_nal_bs_read (bs, 8) == 255) {
/* Extended_SAR */
/* sar_width */
gst_nal_bs_read (bs, 16);
/* sar_height */
gst_nal_bs_read (bs, 16);
}
}
/* overscan_info_present_flag */
if (gst_nal_bs_read (bs, 1)) {
/* overscan_appropriate_flag */
gst_nal_bs_read (bs, 1);
}
/* video_signal_type_present_flag */
if (gst_nal_bs_read (bs, 1)) {
/* video_format */
gst_nal_bs_read (bs, 3);
/* video_full_range_flag */
gst_nal_bs_read (bs, 1);
/* colour_description_present_flag */
if (gst_nal_bs_read (bs, 1)) {
/* colour_primaries */
gst_nal_bs_read (bs, 8);
/* transfer_characteristics */
gst_nal_bs_read (bs, 8);
/* matrix_coefficients */
gst_nal_bs_read (bs, 8);
}
}
/* chroma_loc_info_present_flag */
if (gst_nal_bs_read (bs, 1)) {
/* chroma_sample_loc_type_top_field */
gst_nal_bs_read_ue (bs);
/* chroma_sample_loc_type_bottom_field */
gst_nal_bs_read_ue (bs);
}
sps->timing_info_present_flag = gst_nal_bs_read (bs, 1);
if (sps->timing_info_present_flag) {
guint32 num_units_in_tick = gst_nal_bs_read (bs, 32);
guint32 time_scale = gst_nal_bs_read (bs, 32);
/* If any of these parameters = 0, discard all timing_info */
if (time_scale == 0) {
GST_WARNING_OBJECT (params->el,
"time_scale = 0 detected in stream (incompliant to H.264 E.2.1)."
" Discarding related info.");
} else if (num_units_in_tick == 0) {
GST_WARNING_OBJECT (params->el,
"num_units_in_tick = 0 detected in stream (incompliant to H.264 E.2.1)."
" Discarding related info.");
} else {
sps->num_units_in_tick = num_units_in_tick;
sps->time_scale = time_scale;
sps->fixed_frame_rate_flag = gst_nal_bs_read (bs, 1);
GST_LOG_OBJECT (params->el, "timing info: dur=%d/%d fixed=%d",
num_units_in_tick, time_scale, sps->fixed_frame_rate_flag);
}
}
sps->nal_hrd_parameters_present_flag = gst_nal_bs_read (bs, 1);
if (sps->nal_hrd_parameters_present_flag) {
gst_h264_params_decode_sps_vui_hrd (params, sps, bs);
}
sps->vcl_hrd_parameters_present_flag = gst_nal_bs_read (bs, 1);
if (sps->vcl_hrd_parameters_present_flag) {
gst_h264_params_decode_sps_vui_hrd (params, sps, bs);
}
if (sps->nal_hrd_parameters_present_flag
|| sps->vcl_hrd_parameters_present_flag) {
gst_nal_bs_read (bs, 1); /* low_delay_hrd_flag */
}
sps->pic_struct_present_flag = gst_nal_bs_read (bs, 1);
/* derive framerate */
/* FIXME verify / also handle other cases */
if (sps->fixed_frame_rate_flag && sps->frame_mbs_only_flag &&
!sps->pic_struct_present_flag) {
sps->fps_num = sps->time_scale;
sps->fps_den = sps->num_units_in_tick;
/* picture is a frame = 2 fields */
sps->fps_den *= 2;
GST_LOG_OBJECT (params->el, "framerate %d/%d", sps->fps_num, sps->fps_den);
}
return TRUE;
}
static gboolean
gst_h264_params_decode_sps (GstH264Params * params, GstNalBs * bs)
{
guint8 profile_idc, level_idc;
guint8 sps_id;
GstH264ParamsSPS *sps = NULL;
guint subwc[] = { 1, 2, 2, 1 };
guint subhc[] = { 1, 2, 1, 1 };
guint chroma;
guint fc_top, fc_bottom, fc_left, fc_right;
gint width, height;
profile_idc = gst_nal_bs_read (bs, 8);
/* constraint_set0_flag */
gst_nal_bs_read (bs, 1);
/* constraint_set1_flag */
gst_nal_bs_read (bs, 1);
/* constraint_set1_flag */
gst_nal_bs_read (bs, 1);
/* constraint_set1_flag */
gst_nal_bs_read (bs, 1);
/* reserved */
gst_nal_bs_read (bs, 4);
level_idc = gst_nal_bs_read (bs, 8);
sps_id = gst_nal_bs_read_ue (bs);
sps = gst_h264_params_get_sps (params, sps_id, FALSE);
if (G_UNLIKELY (sps == NULL))
return FALSE;
gst_h264_params_store_nal (params, params->sps_nals, sps_id, bs);
/* could be redefined mid stream, arrange for clear state */
memset (sps, 0, sizeof (*sps));
GST_LOG_OBJECT (params->el, "sps id %d", sps_id);
sps->valid = TRUE;
/* validate and force activate this one if it is the first SPS we see */
if (params->sps == NULL)
params->sps = sps;
sps->profile_idc = profile_idc;
sps->level_idc = level_idc;
if (profile_idc == 100 || profile_idc == 110 || profile_idc == 122
|| profile_idc == 244 || profile_idc == 44 ||
profile_idc == 83 || profile_idc == 86) {
gint scp_flag = 0;
/* chroma_format_idc */
if ((chroma = gst_nal_bs_read_ue (bs)) == 3) {
/* separate_colour_plane_flag */
sps->scp_flag = gst_nal_bs_read (bs, 1);
}
/* bit_depth_luma_minus8 */
gst_nal_bs_read_ue (bs);
/* bit_depth_chroma_minus8 */
gst_nal_bs_read_ue (bs);
/* qpprime_y_zero_transform_bypass_flag */
gst_nal_bs_read (bs, 1);
/* seq_scaling_matrix_present_flag */
if (gst_nal_bs_read (bs, 1)) {
gint i, j, m, d;
m = (chroma != 3) ? 8 : 12;
for (i = 0; i < m; i++) {
/* seq_scaling_list_present_flag[i] */
d = gst_nal_bs_read (bs, 1);
if (d) {
gint lastScale = 8, nextScale = 8, deltaScale;
j = (i < 6) ? 16 : 64;
for (; j > 0; j--) {
if (nextScale != 0) {
deltaScale = gst_nal_bs_read_se (bs);
nextScale = (lastScale + deltaScale + 256) % 256;
}
if (nextScale != 0)
lastScale = nextScale;
}
}
}
}
if (scp_flag)
chroma = 0;
} else {
/* inferred value */
chroma = 1;
}
/* between 0 and 12 */
sps->log2_max_frame_num_minus4 = gst_nal_bs_read_ue (bs);
if (sps->log2_max_frame_num_minus4 > 12) {
GST_WARNING_OBJECT (params->el,
"log2_max_frame_num_minus4 = %d out of range" " [0,12]",
sps->log2_max_frame_num_minus4);
return FALSE;
}
sps->pic_order_cnt_type = gst_nal_bs_read_ue (bs);
if (sps->pic_order_cnt_type == 0) {
sps->log2_max_pic_order_cnt_lsb_minus4 = gst_nal_bs_read_ue (bs);
} else if (sps->pic_order_cnt_type == 1) {
gint d;
/* delta_pic_order_always_zero_flag */
gst_nal_bs_read (bs, 1);
/* offset_for_non_ref_pic */
gst_nal_bs_read_ue (bs);
/* offset_for_top_to_bottom_field */
gst_nal_bs_read_ue (bs);
/* num_ref_frames_in_pic_order_cnt_cycle */
d = gst_nal_bs_read_ue (bs);
for (; d > 0; d--) {
/* offset_for_ref_frame[i] */
gst_nal_bs_read_ue (bs);
}
}
/* max_num_ref_frames */
gst_nal_bs_read_ue (bs);
/* gaps_in_frame_num_value_allowed_flag */
gst_nal_bs_read (bs, 1);
/* pic_width_in_mbs_minus1 */
width = gst_nal_bs_read_ue (bs);
/* pic_height_in_map_units_minus1 */
height = gst_nal_bs_read_ue (bs);
sps->frame_mbs_only_flag = gst_nal_bs_read (bs, 1);
if (!sps->frame_mbs_only_flag) {
/* mb_adaptive_frame_field_flag */
gst_nal_bs_read (bs, 1);
}
width++;
width *= 16;
height++;
height *= 16 * (2 - sps->frame_mbs_only_flag);
/* direct_8x8_inference_flag */
gst_nal_bs_read (bs, 1);
/* frame_cropping_flag */
if (gst_nal_bs_read (bs, 1)) {
/* frame_crop_left_offset */
fc_left = gst_nal_bs_read_ue (bs);
/* frame_crop_right_offset */
fc_right = gst_nal_bs_read_ue (bs);
/* frame_crop_top_offset */
fc_top = gst_nal_bs_read_ue (bs);
/* frame_crop_bottom_offset */
fc_bottom = gst_nal_bs_read_ue (bs);
} else {
fc_left = fc_right = fc_top = fc_bottom = 0;
}
GST_LOG_OBJECT (params->el, "decoding SPS: profile_idc = %d, "
"level_idc = %d, sps_id = %d, pic_order_cnt_type = %d, "
"frame_mbs_only_flag = %d",
sps->profile_idc, sps->level_idc, sps_id, sps->pic_order_cnt_type,
sps->frame_mbs_only_flag);
/* calculate width and height */
GST_LOG_OBJECT (params->el, "initial width=%d, height=%d", width, height);
GST_LOG_OBJECT (params->el, "crop (%d,%d)(%d,%d)",
fc_left, fc_top, fc_right, fc_bottom);
if (chroma > 3) {
GST_LOG_OBJECT (params->el, "chroma=%d in SPS is out of range", chroma);
return FALSE;
}
width -= (fc_left + fc_right) * subwc[chroma];
height -=
(fc_top + fc_bottom) * subhc[chroma] * (2 - sps->frame_mbs_only_flag);
if (width < 0 || height < 0) {
GST_WARNING_OBJECT (params->el, "invalid width/height in SPS");
return FALSE;
}
GST_LOG_OBJECT (params->el, "final width=%u, height=%u", width, height);
sps->width = width;
sps->height = height;
sps->vui_parameters_present_flag = gst_nal_bs_read (bs, 1);
if (sps->vui_parameters_present_flag) {
/* discard parsing problem */
gst_h264_params_decode_sps_vui (params, sps, bs);
}
return TRUE;
}
static gboolean
gst_h264_params_decode_pps (GstH264Params * params, GstNalBs * bs)
{
guint8 pps_id;
GstH264ParamsPPS *pps = NULL;
pps_id = gst_nal_bs_read_ue (bs);
pps = gst_h264_params_get_pps (params, pps_id, FALSE);
if (G_UNLIKELY (pps == NULL))
return FALSE;
/* validate and set */
pps->valid = TRUE;
params->pps = pps;
gst_h264_params_store_nal (params, params->pps_nals, pps_id, bs);
pps->sps_id = gst_nal_bs_read_ue (bs);
GST_LOG_OBJECT (params->el, "pps %d referencing sps %d", pps_id, pps->sps_id);
/* activate referenced sps */
if (!gst_h264_params_get_sps (params, pps->sps_id, TRUE))
return FALSE;
/* not parsing the rest for the time being */
return TRUE;
}
static gboolean
gst_h264_params_decode_sei_buffering_period (GstH264Params * params,
GstNalBs * bs)
{
#ifdef EXTRA_PARSE
guint8 sps_id;
gint sched_sel_idx;
GstH264ParamsSPS *sps;
sps_id = gst_nal_bs_read_ue (bs);
sps = gst_h264_params_get_sps (params, sps_id, TRUE);
if (G_UNLIKELY (sps == NULL))
return FALSE;
if (sps->nal_hrd_parameters_present_flag) {
for (sched_sel_idx = 0; sched_sel_idx <= sps->cpb_cnt_minus1;
sched_sel_idx++) {
params->initial_cpb_removal_delay[sched_sel_idx]
= gst_nal_bs_read (bs,
sps->initial_cpb_removal_delay_length_minus1 + 1);
/* initial_cpb_removal_delay_offset */
gst_nal_bs_read (bs, sps->initial_cpb_removal_delay_length_minus1 + 1);
}
}
if (sps->vcl_hrd_parameters_present_flag) {
for (sched_sel_idx = 0; sched_sel_idx <= sps->cpb_cnt_minus1;
sched_sel_idx++) {
params->initial_cpb_removal_delay[sched_sel_idx]
= gst_nal_bs_read (bs,
sps->initial_cpb_removal_delay_length_minus1 + 1);
/* initial_cpb_removal_delay_offset */
gst_nal_bs_read (bs, sps->initial_cpb_removal_delay_length_minus1 + 1);
}
}
#endif
if (params->ts_trn_nb == GST_CLOCK_TIME_NONE ||
params->dts == GST_CLOCK_TIME_NONE)
params->ts_trn_nb = 0;
else
params->ts_trn_nb = params->dts;
GST_LOG_OBJECT (params->el,
"new buffering period; ts_trn_nb updated: %" GST_TIME_FORMAT,
GST_TIME_ARGS (params->ts_trn_nb));
return 0;
}
static gboolean
gst_h264_params_decode_sei_picture_timing (GstH264Params * params,
GstNalBs * bs)
{
GstH264ParamsSPS *sps = params->sps;
if (sps == NULL) {
GST_WARNING_OBJECT (params->el,
"SPS == NULL; delayed decoding of picture timing info not implemented ");
return FALSE;
}
if (sps->nal_hrd_parameters_present_flag
|| sps->vcl_hrd_parameters_present_flag) {
params->sei_cpb_removal_delay =
gst_nal_bs_read (bs, sps->cpb_removal_delay_length_minus1 + 1);
/* sei_dpb_output_delay */
gst_nal_bs_read (bs, sps->dpb_output_delay_length_minus1 + 1);
}
if (sps->pic_struct_present_flag) {
#ifdef EXTRA_PARSE
/* pic_struct to NumClockTS lookup table */
static const guint8 sei_num_clock_ts_table[9] =
{ 1, 1, 1, 2, 2, 3, 3, 2, 3 };
guint i, num_clock_ts;
guint sei_ct_type = 0;
#endif
params->sei_pic_struct = gst_nal_bs_read (bs, 4);
GST_LOG_OBJECT (params, "pic_struct:%d", params->sei_pic_struct);
if (params->sei_pic_struct > SEI_PIC_STRUCT_FRAME_TRIPLING)
return FALSE;
#ifdef EXTRA_PARSE
num_clock_ts = sei_num_clock_ts_table[params->sei_pic_struct];
for (i = 0; i < num_clock_ts; i++) {
/* clock_timestamp_flag */
if (gst_nal_bs_read (bs, 1)) {
guint full_timestamp_flag;
sei_ct_type |= 1 << gst_nal_bs_read (bs, 2);
/* nuit_field_based_flag */
gst_nal_bs_read (bs, 1);
/* counting_type */
gst_nal_bs_read (bs, 5);
full_timestamp_flag = gst_nal_bs_read (bs, 1);
/* discontinuity_flag */
gst_nal_bs_read (bs, 1);
/* cnt_dropped_flag */
gst_nal_bs_read (bs, 1);
/* n_frames */
gst_nal_bs_read (bs, 8);
if (full_timestamp_flag) {
/* seconds_value 0..59 */
gst_nal_bs_read (bs, 6);
/* minutes_value 0..59 */
gst_nal_bs_read (bs, 6);
/* hours_value 0..23 */
gst_nal_bs_read (bs, 5);
} else {
/* seconds_flag */
if (gst_nal_bs_read (bs, 1)) {
/* seconds_value range 0..59 */
gst_nal_bs_read (bs, 6);
/* minutes_flag */
if (gst_nal_bs_read (bs, 1)) {
/* minutes_value 0..59 */
gst_nal_bs_read (bs, 6);
/* hours_flag */
if (gst_nal_bs_read (bs, 1))
/* hours_value 0..23 */
gst_nal_bs_read (bs, 5);
}
}
}
if (sps->time_offset_length_minus1 >= 0) {
/* time_offset */
gst_nal_bs_read (bs, sps->time_offset_length_minus1 + 1);
}
}
}
GST_LOG_OBJECT (params, "ct_type:%X", sei_ct_type);
#endif
}
return TRUE;
}
static gboolean
gst_h264_params_decode_sei (GstH264Params * params, GstNalBs * bs)
{
guint8 tmp;
GstH264ParamsSEIPayloadType payloadType = 0;
gint8 payloadSize = 0;
do {
tmp = gst_nal_bs_read (bs, 8);
payloadType += tmp;
} while (tmp == 255);
do {
tmp = gst_nal_bs_read (bs, 8);
payloadSize += tmp;
} while (tmp == 255);
GST_LOG_OBJECT (params->el,
"SEI message received: payloadType = %d, payloadSize = %d bytes",
payloadType, payloadSize);
switch (payloadType) {
case SEI_BUF_PERIOD:
if (!gst_h264_params_decode_sei_buffering_period (params, bs))
return FALSE;
break;
case SEI_PIC_TIMING:
/* TODO: According to H264 D2.2 Note1, it might be the case that the
* picture timing SEI message is encountered before the corresponding SPS
* is specified. Need to hold down the message and decode it later. */
if (!gst_h264_params_decode_sei_picture_timing (params, bs))
return FALSE;
break;
default:
GST_LOG_OBJECT (params->el,
"SEI message of payloadType = %d is received but not parsed",
payloadType);
break;
}
return TRUE;
}
static gboolean
gst_h264_params_decode_slice_header (GstH264Params * params, GstNalBs * bs)
{
GstH264ParamsSPS *sps;
GstH264ParamsPPS *pps;
guint8 pps_id;
params->first_mb_in_slice = gst_nal_bs_read_ue (bs);
params->slice_type = gst_nal_bs_read_ue (bs);
pps_id = gst_nal_bs_read_ue (bs);
GST_LOG_OBJECT (params->el, "slice header references pps id %d", pps_id);
pps = gst_h264_params_get_pps (params, pps_id, TRUE);
if (G_UNLIKELY (pps == NULL))
return FALSE;
sps = gst_h264_params_get_sps (params, pps->sps_id, TRUE);
if (G_UNLIKELY (sps == NULL))
return FALSE;
if (sps->scp_flag) {
/* colour_plane_id */
gst_nal_bs_read (bs, 2);
}
/* frame num */
gst_nal_bs_read (bs, sps->log2_max_pic_order_cnt_lsb_minus4 + 4);
if (!sps->frame_mbs_only_flag) {
params->field_pic_flag = gst_nal_bs_read (bs, 1);
if (params->field_pic_flag)
params->bottom_field_flag = gst_nal_bs_read (bs, 1);
}
/* not parsing the rest for the time being */
return TRUE;
}
/* only payload in @data */
gboolean
gst_h264_params_parse_nal (GstH264Params * params, guint8 * data, gint size)
{
GstH264ParamsNalUnitType nal_type;
GstNalBs bs;
gint nal_ref_idc;
gboolean res = TRUE;
g_return_val_if_fail (params != NULL, FALSE);
g_return_val_if_fail (data != NULL, FALSE);
g_return_val_if_fail (size != 0, FALSE);
nal_type = (data[0] & 0x1f);
nal_ref_idc = (data[0] & 0x60) >> 5;
GST_LOG_OBJECT (params->el, "NAL type: %d, ref_idc: %d", nal_type,
nal_ref_idc);
gst_nal_bs_init (&bs, data + 1, size - 1);
/* optimality HACK */
bs.orig_data = data;
/* first parse some things needed to get to the frame type */
switch (nal_type) {
case NAL_SLICE:
case NAL_SLICE_DPA:
case NAL_SLICE_DPB:
case NAL_SLICE_DPC:
case NAL_SLICE_IDR:
{
gint first_mb_in_slice, slice_type;
gst_h264_params_decode_slice_header (params, &bs);
first_mb_in_slice = params->first_mb_in_slice;
slice_type = params->slice_type;
GST_LOG_OBJECT (params->el, "first MB: %d, slice type: %d",
first_mb_in_slice, slice_type);
switch (slice_type) {
case 0:
case 5:
case 3:
case 8: /* SP */
/* P frames */
GST_LOG_OBJECT (params->el, "we have a P slice");
break;
case 1:
case 6:
/* B frames */
GST_LOG_OBJECT (params->el, "we have a B slice");
break;
case 2:
case 7:
case 4:
case 9:
/* I frames */
GST_LOG_OBJECT (params->el, "we have an I slice");
break;
}
break;
}
case NAL_SEI:
GST_LOG_OBJECT (params->el, "SEI NAL");
res = gst_h264_params_decode_sei (params, &bs);
break;
case NAL_SPS:
GST_LOG_OBJECT (params->el, "SPS NAL");
res = gst_h264_params_decode_sps (params, &bs);
break;
case NAL_PPS:
GST_LOG_OBJECT (params->el, "PPS NAL");
res = gst_h264_params_decode_pps (params, &bs);
break;
case NAL_AU_DELIMITER:
GST_LOG_OBJECT (params->el, "AU delimiter NAL");
break;
default:
GST_LOG_OBJECT (params->el, "unparsed NAL");
break;
}
return res;
}
void
gst_h264_params_get_timestamp (GstH264Params * params,
GstClockTime * out_ts, GstClockTime * out_dur, gboolean frame)
{
GstH264ParamsSPS *sps = params->sps;
GstClockTime upstream;
gint duration = 1;
g_return_if_fail (out_dur != NULL);
g_return_if_fail (out_ts != NULL);
upstream = *out_ts;
if (!frame) {
GST_LOG_OBJECT (params->el, "no frame data -> 0 duration");
*out_dur = 0;
goto exit;
} else {
*out_ts = upstream;
}
if (!sps) {
GST_DEBUG_OBJECT (params->el, "referred SPS invalid");
goto exit;
} else if (!sps->timing_info_present_flag) {
GST_DEBUG_OBJECT (params->el,
"unable to compute timestamp: timing info not present");
goto exit;
} else if (sps->time_scale == 0) {
GST_DEBUG_OBJECT (params->el,
"unable to compute timestamp: time_scale = 0 "
"(this is forbidden in spec; bitstream probably contains error)");
goto exit;
}
if (sps->pic_struct_present_flag && params->sei_pic_struct != (guint8) - 1) {
/* Note that when h264parse->sei_pic_struct == -1 (unspecified), there
* are ways to infer its value. This is related to computing the
* TopFieldOrderCnt and BottomFieldOrderCnt, which looks
* complicated and thus not implemented for the time being. Yet
* the value we have here is correct for many applications
*/
switch (params->sei_pic_struct) {
case SEI_PIC_STRUCT_TOP_FIELD:
case SEI_PIC_STRUCT_BOTTOM_FIELD:
duration = 1;
break;
case SEI_PIC_STRUCT_FRAME:
case SEI_PIC_STRUCT_TOP_BOTTOM:
case SEI_PIC_STRUCT_BOTTOM_TOP:
duration = 2;
break;
case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
duration = 3;
break;
case SEI_PIC_STRUCT_FRAME_DOUBLING:
duration = 4;
break;
case SEI_PIC_STRUCT_FRAME_TRIPLING:
duration = 6;
break;
default:
GST_DEBUG_OBJECT (params,
"h264parse->sei_pic_struct of unknown value %d. Not parsed",
params->sei_pic_struct);
break;
}
} else {
duration = params->field_pic_flag ? 1 : 2;
}
GST_LOG_OBJECT (params->el, "frame tick duration %d", duration);
/*
* h264parse.264 C.1.2 Timing of coded picture removal (equivalent to DTS):
* Tr,n(0) = initial_cpb_removal_delay[ SchedSelIdx ] / 90000
* Tr,n(n) = Tr,n(nb) + Tc * cpb_removal_delay(n)
* where
* Tc = num_units_in_tick / time_scale
*/
if (params->ts_trn_nb != GST_CLOCK_TIME_NONE) {
GST_LOG_OBJECT (params->el, "buffering based ts");
/* buffering period is present */
if (upstream != GST_CLOCK_TIME_NONE) {
/* If upstream timestamp is valid, we respect it and adjust current
* reference point */
params->ts_trn_nb = upstream -
(GstClockTime) gst_util_uint64_scale_int
(params->sei_cpb_removal_delay * GST_SECOND,
sps->num_units_in_tick, sps->time_scale);
} else {
/* If no upstream timestamp is given, we write in new timestamp */
upstream = params->dts = params->ts_trn_nb +
(GstClockTime) gst_util_uint64_scale_int
(params->sei_cpb_removal_delay * GST_SECOND,
sps->num_units_in_tick, sps->time_scale);
}
} else {
GstClockTime dur;
GST_LOG_OBJECT (params->el, "duration based ts");
/* naive method: no removal delay specified
* track upstream timestamp and provide best guess frame duration */
dur = gst_util_uint64_scale_int (duration * GST_SECOND,
sps->num_units_in_tick, sps->time_scale);
/* sanity check */
if (dur < GST_MSECOND) {
GST_DEBUG_OBJECT (params->el, "discarding dur %" GST_TIME_FORMAT,
GST_TIME_ARGS (dur));
} else {
*out_dur = dur;
}
}
exit:
if (GST_CLOCK_TIME_IS_VALID (upstream))
*out_ts = params->dts = upstream;
if (GST_CLOCK_TIME_IS_VALID (*out_dur) &&
GST_CLOCK_TIME_IS_VALID (params->dts))
params->dts += *out_dur;
}
void
gst_h264_params_create (GstH264Params ** _params, GstElement * element)
{
GstH264Params *params;
g_return_if_fail (_params != NULL);
params = g_new0 (GstH264Params, 1);
params->el = element;
params->dts = GST_CLOCK_TIME_NONE;
params->ts_trn_nb = GST_CLOCK_TIME_NONE;
*_params = params;
}
void
gst_h264_params_free (GstH264Params * params)
{
gint i;
g_return_if_fail (params != NULL);
for (i = 0; i < MAX_SPS_COUNT; i++)
gst_buffer_replace (&params->sps_nals[i], NULL);
for (i = 0; i < MAX_PPS_COUNT; i++)
gst_buffer_replace (&params->sps_nals[i], NULL);
g_free (params);
}
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