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add S12M timecode support to h264 decoder #15

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62e90e9
lavc/h264: create AVFrame side data from H.264 timecodes
dheitmueller Jun 29, 2018
393c390
h264/pic_timing: support multiple timecodes
Oct 12, 2018
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40 changes: 23 additions & 17 deletions libavcodec/h264_sei.c
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Original file line number Diff line number Diff line change
Expand Up @@ -84,32 +84,38 @@ static int decode_picture_timing(H264SEIPictureTiming *h, GetBitContext *gb,
return AVERROR_INVALIDDATA;

num_clock_ts = sei_num_clock_ts_table[h->pic_struct];

h->timecode_cnt = 0;
for (i = 0; i < num_clock_ts; i++) {
if (get_bits(gb, 1)) { /* clock_timestamp_flag */
if (get_bits(gb, 1)) { /* clock_timestamp_flag */
H264SEITimeCode *tc = &h->timecode[h->timecode_cnt++];
unsigned int full_timestamp_flag;

unsigned int counting_type, cnt_dropped_flag;
h->ct_type |= 1 << get_bits(gb, 2);
skip_bits(gb, 1); /* nuit_field_based_flag */
skip_bits(gb, 5); /* counting_type */
skip_bits(gb, 1); /* nuit_field_based_flag */
counting_type = get_bits(gb, 5); /* counting_type */
full_timestamp_flag = get_bits(gb, 1);
skip_bits(gb, 1); /* discontinuity_flag */
skip_bits(gb, 1); /* cnt_dropped_flag */
skip_bits(gb, 8); /* n_frames */
skip_bits(gb, 1); /* discontinuity_flag */
cnt_dropped_flag = get_bits(gb, 1); /* cnt_dropped_flag */
if (cnt_dropped_flag && counting_type > 1 && counting_type < 7)
tc->dropframe = 1;
tc->frame = get_bits(gb, 8); /* n_frames */
if (full_timestamp_flag) {
skip_bits(gb, 6); /* seconds_value 0..59 */
skip_bits(gb, 6); /* minutes_value 0..59 */
skip_bits(gb, 5); /* hours_value 0..23 */
tc->full = 1;
tc->seconds = get_bits(gb, 6); /* seconds_value 0..59 */
tc->minutes = get_bits(gb, 6); /* minutes_value 0..59 */
tc->hours = get_bits(gb, 5); /* hours_value 0..23 */
} else {
if (get_bits(gb, 1)) { /* seconds_flag */
skip_bits(gb, 6); /* seconds_value range 0..59 */
if (get_bits(gb, 1)) { /* minutes_flag */
skip_bits(gb, 6); /* minutes_value 0..59 */
if (get_bits(gb, 1)) /* hours_flag */
skip_bits(gb, 5); /* hours_value 0..23 */
tc->seconds = tc->minutes = tc->hours = tc->full = 0;
if (get_bits(gb, 1)) { /* seconds_flag */
tc->seconds = get_bits(gb, 6);
if (get_bits(gb, 1)) { /* minutes_flag */
tc->minutes = get_bits(gb, 6);
if (get_bits(gb, 1)) /* hours_flag */
tc->hours = get_bits(gb, 5);
}
}
}

if (sps->time_offset_length > 0)
skip_bits(gb,
sps->time_offset_length); /* time_offset */
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21 changes: 21 additions & 0 deletions libavcodec/h264_sei.h
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Expand Up @@ -63,6 +63,17 @@ typedef enum {
SEI_FPA_TYPE_2D = 6,
} SEI_FpaType;

typedef struct H264SEITimeCode {
/* When not continuously receiving full timecodes, we have to reference
the previous timecode received */
int full;
int frame;
int seconds;
int minutes;
int hours;
int dropframe;
} H264SEITimeCode;

typedef struct H264SEIPictureTiming {
int present;
SEI_PicStructType pic_struct;
Expand All @@ -83,6 +94,16 @@ typedef struct H264SEIPictureTiming {
* cpb_removal_delay in picture timing SEI message, see H.264 C.1.2
*/
int cpb_removal_delay;

/**
* Maximum three timecodes in a pic_timing SEI.
*/
H264SEITimeCode timecode[3];

/**
* Number of timecode in use
*/
int timecode_cnt;
} H264SEIPictureTiming;

typedef struct H264SEIAFD {
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45 changes: 45 additions & 0 deletions libavcodec/h264_slice.c
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Expand Up @@ -1295,6 +1295,51 @@ static int h264_export_frame_props(H264Context *h)
h->avctx->properties |= FF_CODEC_PROPERTY_CLOSED_CAPTIONS;
}

if (h->sei.picture_timing.timecode_cnt > 0) {
uint32_t tc = 0;
uint32_t *tc_sd;

AVFrameSideData *tcside = av_frame_new_side_data(cur->f,
AV_FRAME_DATA_S12M_TIMECODE,
sizeof(uint32_t)*4);
if (!tcside)
return AVERROR(ENOMEM);

tc_sd = (uint32_t*)tcside->data;
tc_sd[0] = h->sei.picture_timing.timecode_cnt;

for (int i = 0; i < tc_sd[0]; i++) {
uint32_t frames;

/* For SMPTE 12-M timecodes, frame count is a special case if > 30 FPS.
See SMPTE ST 12-1:2014 Sec 12.1 for more info. */
if (av_cmp_q(h->avctx->framerate, (AVRational) {30, 1}) == 1) {
frames = h->sei.picture_timing.timecode[i].frame / 2;
if (h->sei.picture_timing.timecode[i].frame % 2 == 1) {
if (av_cmp_q(h->avctx->framerate, (AVRational) {50, 1}) == 0)
tc |= (1 << 7);
else
tc |= (1 << 23);
}
} else {
frames = h->sei.picture_timing.timecode[i].frame;
}

tc |= h->sei.picture_timing.timecode[i].dropframe << 30;
tc |= (frames / 10) << 28;
tc |= (frames % 10) << 24;
tc |= (h->sei.picture_timing.timecode[i].seconds / 10) << 20;
tc |= (h->sei.picture_timing.timecode[i].seconds % 10) << 16;
tc |= (h->sei.picture_timing.timecode[i].minutes / 10) << 12;
tc |= (h->sei.picture_timing.timecode[i].minutes % 10) << 8;
tc |= (h->sei.picture_timing.timecode[i].hours / 10) << 4;
tc |= (h->sei.picture_timing.timecode[i].hours % 10);

tc_sd[i + 1] = tc;
}
h->sei.picture_timing.timecode_cnt = 0;
}

return 0;
}

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1 change: 1 addition & 0 deletions libavutil/frame.c
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Expand Up @@ -778,6 +778,7 @@ const char *av_frame_side_data_name(enum AVFrameSideDataType type)
case AV_FRAME_DATA_MASTERING_DISPLAY_METADATA: return "Mastering display metadata";
case AV_FRAME_DATA_CONTENT_LIGHT_LEVEL: return "Content light level metadata";
case AV_FRAME_DATA_GOP_TIMECODE: return "GOP timecode";
case AV_FRAME_DATA_S12M_TIMECODE: return "SMPTE 12-1 timecode";
}
return NULL;
}
8 changes: 8 additions & 0 deletions libavutil/frame.h
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Expand Up @@ -134,6 +134,14 @@ enum AVFrameSideDataType {
* the form of the AVContentLightMetadata struct.
*/
AV_FRAME_DATA_CONTENT_LIGHT_LEVEL,

/**
* Timecode which conforms to SMPTE ST 12-1. The data is an array of 4 uint32_t
* where the first uint32_t describes how many (1-3) of the other timecodes are used.
* The timecode format is described in the av_timecode_get_smpte_from_framenum()
* function in libavutil/timecode.c.
*/
AV_FRAME_DATA_S12M_TIMECODE,
};

enum AVActiveFormatDescription {
Expand Down