[FFmpeg-devel] [PATCH 1/2] cbs_h265: read/write HEVC PREFIX SEI

Xiang, Haihao haihao.xiang at intel.com
Mon Apr 23 08:55:15 EEST 2018


> On 20/04/18 08:27, Haihao Xiang wrote:
> > Similar to cbs_h264, cbs_h265_{read, write}_nal_unit() can handle HEVC
> > prefix SEI NAL units now. Currently mastering display colour volume SEI
> > message is added only, we may add more SEI message if needed later
> > 
> > Signed-off-by: Haihao Xiang <haihao.xiang at intel.com>
> > ---
> >  libavcodec/cbs_h2645.c                |  43 ++++++++++
> >  libavcodec/cbs_h265.h                 |  38 +++++++++
> >  libavcodec/cbs_h265_syntax_template.c | 150
> > ++++++++++++++++++++++++++++++++++
> >  3 files changed, 231 insertions(+)
> > 
> > diff --git a/libavcodec/cbs_h2645.c b/libavcodec/cbs_h2645.c
> > index 5585831cf6..6fc5832966 100644
> > --- a/libavcodec/cbs_h2645.c
> > +++ b/libavcodec/cbs_h2645.c
> > @@ -29,6 +29,7 @@
> >  #include "h264_sei.h"
> >  #include "h2645_parse.h"
> >  #include "hevc.h"
> > +#include "hevc_sei.h"
> >  
> >  
> >  static int cbs_read_ue_golomb(CodedBitstreamContext *ctx, GetBitContext
> > *gbc,
> > @@ -465,6 +466,26 @@ static void cbs_h265_free_slice(void *unit, uint8_t
> > *content)
> >      av_freep(&content);
> >  }
> >  
> > +static void cbs_h265_free_sei_payload(H265RawSEIPayload *payload)
> > +{
> > +    switch (payload->payload_type) {
> > +    case HEVC_SEI_TYPE_MASTERING_DISPLAY_INFO:
> > +        break;
> > +    default:
> > +        av_buffer_unref(&payload->payload.other.data_ref);
> > +        break;
> > +    }
> > +}
> > +
> > +static void cbs_h265_free_sei(void *unit, uint8_t *content)
> > +{
> > +    H265RawSEI *sei = (H265RawSEI*)content;
> > +    int i;
> > +    for (i = 0; i < sei->payload_count; i++)
> > +        cbs_h265_free_sei_payload(&sei->payload[i]);
> > +    av_freep(&content);
> > +}
> > +
> >  static int cbs_h2645_fragment_add_nals(CodedBitstreamContext *ctx,
> >                                         CodedBitstreamFragment *frag,
> >                                         const H2645Packet *packet)
> > @@ -972,6 +993,20 @@ static int cbs_h265_read_nal_unit(CodedBitstreamContext
> > *ctx,
> >          }
> >          break;
> >  
> > +    case HEVC_NAL_SEI_PREFIX:
> 
> I don't think it would be too hard to handling SEI_SUFFIX here too?  (The
> different set of valid payloads doesn't matter when we aren't checking that
> below.)
> 

I also don't think so. But it seems most pre-defined SEI types in hevc_sei.h are
SEI_PREFIX, hence my thought is we may add support for SEI_SUFFIX in the future
if SEI_SUFFIX is really needed.

> > +        err = ff_cbs_alloc_unit_content(ctx, unit, sizeof(H265RawSEI),
> > +                                        &cbs_h265_free_sei);
> > +
> > +        if (err < 0)
> > +            return err;
> > +
> > +        err = cbs_h265_read_sei(ctx, &gbc, unit->content);
> > +
> > +        if (err < 0)
> > +            return err;
> > +
> > +        break;
> > +
> >      default:
> >          return AVERROR(ENOSYS);
> >      }
> > @@ -1212,6 +1247,14 @@ static int
> > cbs_h265_write_nal_unit(CodedBitstreamContext *ctx,
> >          }
> >          break;
> >  
> > +    case HEVC_NAL_SEI_PREFIX:
> > +        err = cbs_h265_write_sei(ctx, pbc, unit->content);
> > +
> > +        if (err < 0)
> > +            return err;
> > +
> > +        break;
> > +
> 
> Please make these cases match the styling of the others.
> 

My original patch used the same coding style of the others, but patcheck in
FFmpeg reported a warning below:

{ should be on the same line as the related previous statement
0001-vaapi_encode_h265-Insert-SEI-if-needed.patch:24:+        {

I will update it if you prefer the same coding style. 

> >      default:
> >          av_log(ctx->log_ctx, AV_LOG_ERROR, "Write unimplemented for "
> >                 "NAL unit type %"PRIu32".\n", unit->type);
> > diff --git a/libavcodec/cbs_h265.h b/libavcodec/cbs_h265.h
> > index 33e71fc234..e37c1b8d94 100644
> > --- a/libavcodec/cbs_h265.h
> > +++ b/libavcodec/cbs_h265.h
> > @@ -25,6 +25,14 @@
> >  #include "cbs_h2645.h"
> >  #include "hevc.h"
> >  
> > +enum {
> > +    // This limit is arbitrary - it is sufficient for one message of each
> > +    // type plus some repeats, and will therefore easily cover all sane
> > +    // streams.  However, it is possible to make technically-valid streams
> > +    // for which it will fail (for example, by including a large number of
> > +    // user-data-unregistered messages).
> > +    H265_MAX_SEI_PAYLOADS = 64,
> > +};
> >  
> >  typedef struct H265RawNALUnitHeader {
> >      uint8_t forbidden_zero_bit;
> > @@ -516,6 +524,36 @@ typedef struct H265RawSlice {
> >      AVBufferRef *data_ref;
> >  } H265RawSlice;
> >  
> > +typedef struct H265RawSEIMasteringDiplayColorVolume {
> 
> The H.265 standard uses English spelling of colour, not USAian.

Thanks, I will update it.

> 
> > +    struct {
> > +        uint16_t x;
> > +        uint16_t y;
> > +    } display_primaries[3];
> 
> Make it two arrays, display_primaries_x and display_primaries_y, so that it
> matches the standard.

Thanks, I will update it.

> 
> > +    uint16_t white_point_x;
> > +    uint16_t white_point_y;
> > +    uint32_t max_display_mastering_luminance;
> > +    uint32_t min_display_mastering_luminance;
> > +} H265RawSEIMasteringDiplayColorVolume;
> > +
> > +typedef struct H265RawSEIPayload {
> > +    uint32_t payload_type;
> > +    uint32_t payload_size;
> > +    union {
> > +        H265RawSEIMasteringDiplayColorVolume mastering_display;
> > +        struct {
> > +            uint8_t *data;
> > +            size_t data_length;
> > +            AVBufferRef *data_ref;
> > +        } other;
> > +    } payload;
> > +} H265RawSEIPayload;
> > +
> > +typedef struct H265RawSEI {
> > +    H265RawNALUnitHeader nal_unit_header;
> > +
> > +    H265RawSEIPayload payload[H265_MAX_SEI_PAYLOADS];
> > +    uint8_t payload_count;
> > +} H265RawSEI;
> >  
> >  typedef struct CodedBitstreamH265Context {
> >      // Reader/writer context in common with the H.264 implementation.
> > diff --git a/libavcodec/cbs_h265_syntax_template.c
> > b/libavcodec/cbs_h265_syntax_template.c
> > index 140c827c9d..cbe8f30be0 100644
> > --- a/libavcodec/cbs_h265_syntax_template.c
> > +++ b/libavcodec/cbs_h265_syntax_template.c
> > @@ -1501,3 +1501,153 @@ static int
> > FUNC(slice_segment_header)(CodedBitstreamContext *ctx, RWContext *rw,
> >  
> >      return 0;
> >  }
> > +
> > +static int FUNC(sei_mastering_display)(CodedBitstreamContext *ctx,
> > RWContext *rw,
> > +                                       H265RawSEIMasteringDiplayColorVolume
> > *current)
> > +{
> > +    int err, i;
> > +
> > +    for (i = 0; i < 3; i++) {
> 
> This variable is called 'c' in the standard (which matters when it ends up in
> the trace name).

Thanks, I will update it.

> 
> > +        xu(16, display_primaries_x, current->display_primaries[i].x, 0,
> > 50000);
> > +        xu(16, display_primaries_y, current->display_primaries[i].y, 0,
> > 50000);
> > +    }
> > +
> > +    xu(16, white_point_x, current->white_point_x, 0, 50000);
> > +    xu(16, white_point_y, current->white_point_y, 0, 50000);
> > +
> > +    xu(32, max_display_mastering_luminance, current-
> > >max_display_mastering_luminance, 0, 0xFFFFFFFF);
> 
> MAX_UINT_BITS(32)
> 
> Also break the overlong line.

Thanks, I will update it.

> 
> > +    xu(32, min_display_mastering_luminance, current-
> > >min_display_mastering_luminance, 0, 0xFFFFFFFF);
> 
> You could use "min_display_mastering_luminance shall be less than
> max_display_mastering_luminance" as a bound here?

yes, i will update it.

> 
> All of these should use the u() macro rather than xu(), since they aren't
> writing to a different variable.
> 

OK, I will use the u() macro in the new version of the patch.

> > +
> > +    return 0;
> > +}
> > +
> > +static int FUNC(sei_payload)(CodedBitstreamContext *ctx, RWContext *rw,
> > +                             H265RawSEIPayload *current)
> > +{
> > +    int err, i;
> > +    int start_position, end_position;
> > +
> > +#ifdef READ
> > +    start_position = get_bits_count(rw);
> > +#else
> > +    start_position = put_bits_count(rw);
> > +#endif
> > +
> > +    switch (current->payload_type) {
> > +    case HEVC_SEI_TYPE_MASTERING_DISPLAY_INFO:
> > +        CHECK(FUNC(sei_mastering_display)
> > +              (ctx, rw, &current->payload.mastering_display));
> > +
> > +        break;
> > +
> > +    default:
> > +        allocate(current->payload.other.data, current->payload_size);
> > +
> > +        for (i = 0; i < current->payload_size; i++)
> > +            xu(8, payload_byte, current->payload.other.data[i], 0, 255);
> > +    }
> > +
> > +    if (byte_alignment(rw)) {
> > +        av_unused int one = 1, zero = 0;
> > +        xu(1, bit_equal_to_one, one, 1, 1);
> > +        while (byte_alignment(rw))
> > +            xu(1, bit_equal_to_zero, zero, 0, 0);
> > +    }
> > +
> > +#ifdef READ
> > +    end_position = get_bits_count(rw);
> > +    if (end_position < start_position + 8 * current->payload_size) {
> > +        av_log(ctx->log_ctx, AV_LOG_ERROR, "Incorrect SEI payload length: "
> > +               "header %"PRIu32" bits, actually %d bits.\n",
> > +               8 * current->payload_size,
> > +               end_position - start_position);
> > +        return AVERROR_INVALIDDATA;
> > +    }
> > +#else
> > +    end_position = put_bits_count(rw);
> > +    current->payload_size = (end_position - start_position) >> 3;
> > +#endif
> > +
> > +    return 0;
> > +}
> > +
> > +static int FUNC(sei)(CodedBitstreamContext *ctx, RWContext *rw,
> > +                     H265RawSEI *current)
> > +{
> > +    int err, k;
> > +
> > +    HEADER("Supplemental Enhancement Information");
> > +
> > +    CHECK(FUNC(nal_unit_header)(ctx, rw, &current->nal_unit_header,
> > HEVC_NAL_SEI_PREFIX));
> > +
> > +#ifdef READ
> > +    for (k = 0; k < H265_MAX_SEI_PAYLOADS; k++) {
> > +        uint32_t payload_type = 0;
> > +        uint32_t payload_size = 0;
> > +        uint32_t tmp;
> > +
> > +        while (show_bits(rw, 8) == 0xff) {
> > +            xu(8, ff_byte, tmp, 0xff, 0xff);
> > +            payload_type += 255;
> > +        }
> > +        xu(8, last_payload_type_byte, tmp, 0, 254);
> > +        payload_type += tmp;
> > +
> > +        while (show_bits(rw, 8) == 0xff) {
> > +            xu(8, ff_byte, tmp, 0xff, 0xff);
> > +            payload_size += 255;
> > +        }
> > +        xu(8, last_payload_size_byte, tmp, 0, 254);
> > +        payload_size += tmp;
> > +
> > +        current->payload[k].payload_type = payload_type;
> > +        current->payload[k].payload_size = payload_size;
> > +
> > +        CHECK(FUNC(sei_payload)(ctx, rw, &current->payload[k]));
> > +
> > +        if (!cbs_h2645_read_more_rbsp_data(rw))
> > +            break;
> > +    }
> > +    if (k >= H265_MAX_SEI_PAYLOADS) {
> > +        av_log(ctx->log_ctx, AV_LOG_ERROR, "Too many payloads in "
> > +               "SEI message: found %d.\n", k);
> > +        return AVERROR_INVALIDDATA;
> > +    }
> > +    current->payload_count = k + 1;
> > +#else
> > +    for (k = 0; k < current->payload_count; k++) {
> > +        PutBitContext start_state;
> > +        uint32_t tmp;
> > +        int need_size, i;
> > +
> > +        // Somewhat clumsy: we write the payload twice when
> > +        // we don't know the size in advance.  This will mess
> > +        // with trace output, but is otherwise harmless.
> > +        start_state = *rw;
> > +        need_size = !current->payload[k].payload_size;
> > +        for (i = 0; i < 1 + need_size; i++) {
> > +            *rw = start_state;
> > +
> > +            tmp = current->payload[k].payload_type;
> > +            while (tmp >= 255) {
> > +                xu(8, ff_byte, 0xff, 0xff, 0xff);
> > +                tmp -= 255;
> > +            }
> > +            xu(8, last_payload_type_byte, tmp, 0, 254);
> > +
> > +            tmp = current->payload[k].payload_size;
> > +            while (tmp >= 255) {
> > +                xu(8, ff_byte, 0xff, 0xff, 0xff);
> > +                tmp -= 255;
> > +            }
> > +            xu(8, last_payload_size_byte, tmp, 0, 254);
> > +
> > +            CHECK(FUNC(sei_payload)(ctx, rw, &current->payload[k]));
> > +        }
> > +    }
> > +#endif
> 
> I admit you're copying what I wrote in the equivalent code for H.264, but this
> is still kindof horrible.  Any thoughts on how to do this more nicely are
> welcome...

Do you mean writing the payload twice in the code or re-using the code in this
way? 


> > +
> > +    CHECK(FUNC(rbsp_trailing_bits)(ctx, rw));
> > +
> > +    return 0;
> > +}
> > 
> 
> Looks generally ok, thank you for working on this!

Thanks for your review, I will update the patch. 

> 
> - Mark
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