/**
* Decode the group of blocks header or slice header.
* @return <0 if an error occurred
*/
static int h261_decode_gob_header(H261Context *h)
{
unsigned int val;
MpegEncContext *const s = &h->s;
if (!h->gob_start_code_skipped) {
/* Check for GOB Start Code */
val = show_bits(&s->gb, 15);
if (val)
return -1;
/* We have a GBSC */
skip_bits(&s->gb, 16);
}
h->gob_start_code_skipped = 0;
h->gob_number = get_bits(&s->gb, 4); /* GN */
s->qscale = get_bits(&s->gb, 5); /* GQUANT */
/* Check if gob_number is valid */
if (s->mb_height == 18) { // CIF
if ((h->gob_number <= 0) || (h->gob_number > 12))
return -1;
} else { // QCIF
if ((h->gob_number != 1) && (h->gob_number != 3) &&
(h->gob_number != 5))
return -1;
}
/* GEI */
if (skip_1stop_8data_bits(&s->gb) < 0)
return AVERROR_INVALIDDATA;
if (s->qscale == 0) {
av_log(s->avctx, AV_LOG_ERROR, "qscale has forbidden 0 value\n");
if (s->avctx->err_recognition & (AV_EF_BITSTREAM | AV_EF_COMPLIANT))
return -1;
}
/* For the first transmitted macroblock in a GOB, MBA is the absolute
* address. For subsequent macroblocks, MBA is the difference between
* the absolute addresses of the macroblock and the last transmitted
* macroblock. */
h->current_mba = 0;
h->mba_diff = 0;
return 0;
}
int ff_flv_decode_picture_header(MpegEncContext *s)
{
int format, width, height;
/* picture header */
if (get_bits_long(&s->gb, 17) != 1) {
av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
return AVERROR_INVALIDDATA;
}
format = get_bits(&s->gb, 5);
if (format != 0 && format != 1) {
av_log(s->avctx, AV_LOG_ERROR, "Bad picture format\n");
return AVERROR_INVALIDDATA;
}
s->h263_flv = format + 1;
s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */
format = get_bits(&s->gb, 3);
switch (format) {
case 0:
width = get_bits(&s->gb, 8);
height = get_bits(&s->gb, 8);
break;
case 1:
width = get_bits(&s->gb, 16);
height = get_bits(&s->gb, 16);
break;
case 2:
width = 352;
height = 288;
break;
case 3:
width = 176;
height = 144;
break;
case 4:
width = 128;
height = 96;
break;
case 5:
width = 320;
height = 240;
break;
case 6:
width = 160;
height = 120;
break;
default:
width = height = 0;
break;
}
if (av_image_check_size(width, height, 0, s->avctx))
return AVERROR(EINVAL);
s->width = width;
s->height = height;
s->pict_type = AV_PICTURE_TYPE_I + get_bits(&s->gb, 2);
s->droppable = s->pict_type > AV_PICTURE_TYPE_P;
if (s->droppable)
s->pict_type = AV_PICTURE_TYPE_P;
skip_bits1(&s->gb); /* deblocking flag */
s->chroma_qscale = s->qscale = get_bits(&s->gb, 5);
s->h263_plus = 0;
s->unrestricted_mv = 1;
s->h263_long_vectors = 0;
/* PEI */
if (skip_1stop_8data_bits(&s->gb) < 0)
return AVERROR_INVALIDDATA;
s->f_code = 1;
if (s->ehc_mode)
s->avctx->sample_aspect_ratio= (AVRational){1,2};
if (s->avctx->debug & FF_DEBUG_PICT_INFO) {
av_log(s->avctx, AV_LOG_DEBUG, "%c esc_type:%d, qp:%d num:%d\n",
s->droppable ? 'D' : av_get_picture_type_char(s->pict_type),
s->h263_flv - 1, s->qscale, s->picture_number);
}
s->y_dc_scale_table = s->c_dc_scale_table = ff_mpeg1_dc_scale_table;
return 0;
}
/**
* Decode the H.261 picture header.
* @return <0 if no startcode found
*/
static int h261_decode_picture_header(H261Context *h)
{
MpegEncContext *const s = &h->s;
int format, i;
uint32_t startcode = 0;
for (i = get_bits_left(&s->gb); i > 24; i -= 1) {
startcode = ((startcode << 1) | get_bits(&s->gb, 1)) & 0x000FFFFF;
if (startcode == 0x10)
break;
}
if (startcode != 0x10) {
av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
return -1;
}
/* temporal reference */
i = get_bits(&s->gb, 5); /* picture timestamp */
if (i < (s->picture_number & 31))
i += 32;
s->picture_number = (s->picture_number & ~31) + i;
#ifdef IDE_COMPILE
s->avctx->time_base.num = 1001;
s->avctx->time_base.den = 30000;
#else
s->avctx->time_base = (AVRational) { 1001, 30000 };
#endif
/* PTYPE starts here */
skip_bits1(&s->gb); /* split screen off */
skip_bits1(&s->gb); /* camera off */
skip_bits1(&s->gb); /* freeze picture release off */
format = get_bits1(&s->gb);
// only 2 formats possible
if (format == 0) { // QCIF
s->width = 176;
s->height = 144;
s->mb_width = 11;
s->mb_height = 9;
} else { // CIF
s->width = 352;
s->height = 288;
s->mb_width = 22;
s->mb_height = 18;
}
s->mb_num = s->mb_width * s->mb_height;
skip_bits1(&s->gb); /* still image mode off */
skip_bits1(&s->gb); /* Reserved */
/* PEI */
if (skip_1stop_8data_bits(&s->gb) < 0)
return AVERROR_INVALIDDATA;
/* H.261 has no I-frames, but if we pass AV_PICTURE_TYPE_I for the first
* frame, the codec crashes if it does not contain all I-blocks
* (e.g. when a packet is lost). */
s->pict_type = AV_PICTURE_TYPE_P;
h->gob_number = 0;
return 0;
}
/* don't understand why they choose a different header ! */
int ff_intel_h263_decode_picture_header(MpegEncContext *s)
{
int format;
if (get_bits_left(&s->gb) == 64) { /* special dummy frames */
return FRAME_SKIPPED;
}
/* picture header */
if (get_bits_long(&s->gb, 22) != 0x20) {
av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
return -1;
}
s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */
if (check_marker(&s->gb, "after picture_number") != 1) {
return -1; /* marker */
}
if (get_bits1(&s->gb) != 0) {
av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
return -1; /* h263 id */
}
skip_bits1(&s->gb); /* split screen off */
skip_bits1(&s->gb); /* camera off */
skip_bits1(&s->gb); /* freeze picture release off */
format = get_bits(&s->gb, 3);
if (format == 0 || format == 6) {
av_log(s->avctx, AV_LOG_ERROR, "Intel H263 free format not supported\n");
return -1;
}
s->h263_plus = 0;
s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
s->h263_long_vectors = get_bits1(&s->gb);
if (get_bits1(&s->gb) != 0) {
av_log(s->avctx, AV_LOG_ERROR, "SAC not supported\n");
return -1; /* SAC: off */
}
s->obmc= get_bits1(&s->gb);
s->unrestricted_mv = s->obmc || s->h263_long_vectors;
s->pb_frame = get_bits1(&s->gb);
if (format < 6) {
s->width = ff_h263_format[format][0];
s->height = ff_h263_format[format][1];
s->avctx->sample_aspect_ratio.num = 12;
s->avctx->sample_aspect_ratio.den = 11;
} else {
format = get_bits(&s->gb, 3);
if(format == 0 || format == 7){
av_log(s->avctx, AV_LOG_ERROR, "Wrong Intel H263 format\n");
return -1;
}
if(get_bits(&s->gb, 2))
av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
s->loop_filter = get_bits1(&s->gb) * !s->avctx->lowres;
if(get_bits1(&s->gb))
av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
if(get_bits1(&s->gb))
s->pb_frame = 2;
if(get_bits(&s->gb, 5))
av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
if(get_bits(&s->gb, 5) != 1)
av_log(s->avctx, AV_LOG_ERROR, "Invalid marker\n");
}
if(format == 6){
int ar = get_bits(&s->gb, 4);
skip_bits(&s->gb, 9); // display width
check_marker(&s->gb, "in dimensions");
skip_bits(&s->gb, 9); // display height
if(ar == 15){
s->avctx->sample_aspect_ratio.num = get_bits(&s->gb, 8); // aspect ratio - width
s->avctx->sample_aspect_ratio.den = get_bits(&s->gb, 8); // aspect ratio - height
} else {
s->avctx->sample_aspect_ratio = ff_h263_pixel_aspect[ar];
}
if (s->avctx->sample_aspect_ratio.num == 0)
av_log(s->avctx, AV_LOG_ERROR, "Invalid aspect ratio.\n");
}
s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
if(s->pb_frame){
skip_bits(&s->gb, 3); //temporal reference for B-frame
skip_bits(&s->gb, 2); //dbquant
}
/* PEI */
if (skip_1stop_8data_bits(&s->gb) < 0)
return AVERROR_INVALIDDATA;
s->f_code = 1;
s->y_dc_scale_table=
s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
ff_h263_show_pict_info(s);
return 0;
}
