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dirac: add Comments and references to the standard 

Signed-off-by: Diego Biurrun <diego@biurrun.de>
tags/n1.0
Jordi Ortiz Diego Biurrun 13 years ago
parent
06e751a40f
commit
43da682c87
1 changed files with 61 additions and 19 deletions
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  1. +61
    -19
      libavcodec/dirac.c

+ 61
- 19
libavcodec/dirac.c View File

@@ -58,6 +58,7 @@ static const dirac_source_params dirac_source_parameters_defaults[] = {
{ 7680, 4320, 1, 0, 1, 6, 1, 3840, 2160, 0, 0, 3, 3 },
};

/* [DIRAC_STD] Table 10.4 - Available preset pixel aspect ratio values */
static const AVRational dirac_preset_aspect_ratios[] = {
{1, 1},
{10, 11},
@@ -67,11 +68,16 @@ static const AVRational dirac_preset_aspect_ratios[] = {
{4, 3},
};

/* [DIRAC_STD] Values 9,10 of 10.3.5 Frame Rate.
* Table 10.3 Available preset frame rate values
*/
static const AVRational dirac_frame_rate[] = {
{15000, 1001},
{25, 2},
};

/* [DIRAC_STD] This should be equivalent to Table 10.5 Available signal
* range presets */
static const struct {
uint8_t bitdepth;
enum AVColorRange color_range;
@@ -100,11 +106,14 @@ static const struct {
{ AVCOL_PRI_BT709, AVCOL_SPC_BT709, AVCOL_TRC_UNSPECIFIED /* DCinema */ },
};

/* [DIRAC_STD] Table 10.2 Supported chroma sampling formats + luma Offset */
static const enum PixelFormat dirac_pix_fmt[2][3] = {
{ PIX_FMT_YUV444P, PIX_FMT_YUV422P, PIX_FMT_YUV420P },
{ PIX_FMT_YUVJ444P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ420P },
};

/* [DIRAC_STD] 10.3 Parse Source Parameters.
* source_parameters(base_video_format) */
static int parse_source_parameters(AVCodecContext *avctx, GetBitContext *gb,
dirac_source_params *source)
{
@@ -112,13 +121,18 @@ static int parse_source_parameters(AVCodecContext *avctx, GetBitContext *gb,
unsigned luma_depth = 8, luma_offset = 16;
int idx;

/* [DIRAC_STD] 10.3.2 Frame size. frame_size(video_params) */
/* [DIRAC_STD] custom_dimensions_flag */
if (get_bits1(gb)) {
source->width = svq3_get_ue_golomb(gb);
source->height = svq3_get_ue_golomb(gb);
source->width = svq3_get_ue_golomb(gb); /* [DIRAC_STD] FRAME_WIDTH */
source->height = svq3_get_ue_golomb(gb); /* [DIRAC_STD] FRAME_HEIGHT */
}

// chroma subsampling
/* [DIRAC_STD] 10.3.3 Chroma Sampling Format.
* chroma_sampling_format(video_params) */
/* [DIRAC_STD] custom_chroma_format_flag */
if (get_bits1(gb))
/* [DIRAC_STD] CHROMA_FORMAT_INDEX */
source->chroma_format = svq3_get_ue_golomb(gb);
if (source->chroma_format > 2) {
av_log(avctx, AV_LOG_ERROR, "Unknown chroma format %d\n",
@@ -126,34 +140,43 @@ static int parse_source_parameters(AVCodecContext *avctx, GetBitContext *gb,
return AVERROR_INVALIDDATA;
}

/* [DIRAC_STD] 10.3.4 Scan Format. scan_format(video_params) */
/* [DIRAC_STD] custom_scan_format_flag */
if (get_bits1(gb))
/* [DIRAC_STD] SOURCE_SAMPLING */
source->interlaced = svq3_get_ue_golomb(gb);
if (source->interlaced > 1)
return AVERROR_INVALIDDATA;

// frame rate
if (get_bits1(gb)) {
/* [DIRAC_STD] 10.3.5 Frame Rate. frame_rate(video_params) */
if (get_bits1(gb)) { /* [DIRAC_STD] custom_frame_rate_flag */
source->frame_rate_index = svq3_get_ue_golomb(gb);

if (source->frame_rate_index > 10)
return AVERROR_INVALIDDATA;

if (!source->frame_rate_index) {
/* [DIRAC_STD] FRAME_RATE_NUMER */
frame_rate.num = svq3_get_ue_golomb(gb);
/* [DIRAC_STD] FRAME_RATE_DENOM */
frame_rate.den = svq3_get_ue_golomb(gb);
}
}
/* [DIRAC_STD] preset_frame_rate(video_params, index) */
if (source->frame_rate_index > 0) {
if (source->frame_rate_index <= 8)
frame_rate = avpriv_frame_rate_tab[source->frame_rate_index];
else
/* [DIRAC_STD] Table 10.3 values 9-10 */
frame_rate = dirac_frame_rate[source->frame_rate_index-9];
}
av_reduce(&avctx->time_base.num, &avctx->time_base.den,
frame_rate.den, frame_rate.num, 1<<30);

// aspect ratio
if (get_bits1(gb)) {
/* [DIRAC_STD] 10.3.6 Pixel Aspect Ratio.
* pixel_aspect_ratio(video_params) */
if (get_bits1(gb)) { /* [DIRAC_STD] custom_pixel_aspect_ratio_flag */
/* [DIRAC_STD] index */
source->aspect_ratio_index = svq3_get_ue_golomb(gb);

if (source->aspect_ratio_index > 6)
@@ -164,19 +187,29 @@ static int parse_source_parameters(AVCodecContext *avctx, GetBitContext *gb,
avctx->sample_aspect_ratio.den = svq3_get_ue_golomb(gb);
}
}
/* [DIRAC_STD] Take value from Table 10.4 Available preset pixel
* aspect ratio values */
if (source->aspect_ratio_index > 0)
avctx->sample_aspect_ratio =
dirac_preset_aspect_ratios[source->aspect_ratio_index-1];

if (get_bits1(gb)) {
/* [DIRAC_STD] 10.3.7 Clean area. clean_area(video_params) */
if (get_bits1(gb)) { /* [DIRAC_STD] custom_clean_area_flag */
/* [DIRAC_STD] CLEAN_WIDTH */
source->clean_width = svq3_get_ue_golomb(gb);
/* [DIRAC_STD] CLEAN_HEIGHT */
source->clean_height = svq3_get_ue_golomb(gb);
/* [DIRAC_STD] CLEAN_LEFT_OFFSET */
source->clean_left_offset = svq3_get_ue_golomb(gb);
/* [DIRAC_STD] CLEAN_RIGHT_OFFSET */
source->clean_right_offset = svq3_get_ue_golomb(gb);
}

// Override signal range.
if (get_bits1(gb)) {
/* [DIRAC_STD] 10.3.8 Signal range. signal_range(video_params)
* WARNING: Some adaptation seems to be done using the
* AVCOL_RANGE_MPEG/JPEG values */
if (get_bits1(gb)) { /* [DIRAC_STD] custom_signal_range_flag */
/* [DIRAC_STD] index */
source->pixel_range_index = svq3_get_ue_golomb(gb);

if (source->pixel_range_index > 4)
@@ -186,12 +219,13 @@ static int parse_source_parameters(AVCodecContext *avctx, GetBitContext *gb,
if (!source->pixel_range_index) {
luma_offset = svq3_get_ue_golomb(gb);
luma_depth = av_log2(svq3_get_ue_golomb(gb))+1;
svq3_get_ue_golomb(gb); // chroma offset
svq3_get_ue_golomb(gb); // chroma excursion

svq3_get_ue_golomb(gb); /* chroma offset */
svq3_get_ue_golomb(gb); /* chroma excursion */
avctx->color_range = luma_offset ? AVCOL_RANGE_MPEG : AVCOL_RANGE_JPEG;
}
}
/* [DIRAC_STD] Table 10.5
* Available signal range presets <--> pixel_range_presets */
if (source->pixel_range_index > 0) {
idx = source->pixel_range_index-1;
luma_depth = pixel_range_presets[idx].bitdepth;
@@ -203,8 +237,9 @@ static int parse_source_parameters(AVCodecContext *avctx, GetBitContext *gb,

avctx->pix_fmt = dirac_pix_fmt[!luma_offset][source->chroma_format];

// color spec
if (get_bits1(gb)) {
/* [DIRAC_STD] 10.3.9 Colour specification. colour_spec(video_params) */
if (get_bits1(gb)) { /* [DIRAC_STD] custom_colour_spec_flag */
/* [DIRAC_STD] index */
idx = source->color_spec_index = svq3_get_ue_golomb(gb);

if (source->color_spec_index > 4)
@@ -215,12 +250,13 @@ static int parse_source_parameters(AVCodecContext *avctx, GetBitContext *gb,
avctx->color_trc = dirac_color_presets[idx].color_trc;

if (!source->color_spec_index) {
/* [DIRAC_STD] 10.3.9.1 Colour primaries */
if (get_bits1(gb)) {
idx = svq3_get_ue_golomb(gb);
if (idx < 3)
avctx->color_primaries = dirac_primaries[idx];
}
/* [DIRAC_STD] 10.3.9.2 Colour matrix */
if (get_bits1(gb)) {
idx = svq3_get_ue_golomb(gb);
if (!idx)
@@ -228,7 +264,7 @@ static int parse_source_parameters(AVCodecContext *avctx, GetBitContext *gb,
else if (idx == 1)
avctx->colorspace = AVCOL_SPC_BT470BG;
}
/* [DIRAC_STD] 10.3.9.3 Transfer function */
if (get_bits1(gb) && !svq3_get_ue_golomb(gb))
avctx->color_trc = AVCOL_TRC_BT709;
}
@@ -242,6 +278,7 @@ static int parse_source_parameters(AVCodecContext *avctx, GetBitContext *gb,
return 0;
}

/* [DIRAC_STD] 10. Sequence Header. sequence_header() */
int avpriv_dirac_parse_sequence_header(AVCodecContext *avctx, GetBitContext *gb,
dirac_source_params *source)
{
@@ -249,10 +286,13 @@ int avpriv_dirac_parse_sequence_header(AVCodecContext *avctx, GetBitContext *gb,
unsigned video_format, picture_coding_mode;
int ret;

/* [DIRAC_SPEC] 10.1 Parse Parameters. parse_parameters() */
version_major = svq3_get_ue_golomb(gb);
svq3_get_ue_golomb(gb); /* version_minor */
avctx->profile = svq3_get_ue_golomb(gb);
avctx->level = svq3_get_ue_golomb(gb);
/* [DIRAC_SPEC] sequence_header() -> base_video_format as defined in
* 10.2 Base Video Format, table 10.1 Dirac predefined video formats */
video_format = svq3_get_ue_golomb(gb);

if (version_major < 2)
@@ -266,7 +306,8 @@ int avpriv_dirac_parse_sequence_header(AVCodecContext *avctx, GetBitContext *gb,
// Fill in defaults for the source parameters.
*source = dirac_source_parameters_defaults[video_format];

// Override the defaults.
/* [DIRAC_STD] 10.3 Source Parameters
* Override the defaults. */
if (ret = parse_source_parameters(avctx, gb, source))
return ret;

@@ -275,7 +316,8 @@ int avpriv_dirac_parse_sequence_header(AVCodecContext *avctx, GetBitContext *gb,

avcodec_set_dimensions(avctx, source->width, source->height);

// currently only used to signal field coding
/* [DIRAC_STD] picture_coding_mode shall be 0 for fields and 1 for frames
* currently only used to signal field coding */
picture_coding_mode = svq3_get_ue_golomb(gb);
if (picture_coding_mode != 0) {
av_log(avctx, AV_LOG_ERROR, "Unsupported picture coding mode %d",


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