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decoder: h264: add support for missing second field.
Interlaced H.264 video frames always have two fields to decode and display. However, in some cases, e.g. packet loss, one of the field can be missing. This perturbs the reference picture marking process, whereby the number of references available in DPB no longer matches the expected value. This patch adds initial support for missing field within a decoded frame. The current strategy taken is to find out the nearest field, by POC value, and with the same parity. https://bugzilla.gnome.org/show_bug.cgi?id=745048
This commit is contained in:
Gwenole Beauchesne
parent
4776138d4a
commit
efaadfc7c0
1 changed files with 151 additions and 18 deletions
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@ -160,6 +160,9 @@ gst_vaapi_parser_info_h264_new(void)
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* access unit (AU)
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* @GST_VAAPI_PICTURE_FLAG_AU_END: flag that marks the end of an
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* access unit (AU)
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* @GST_VAAPI_PICTURE_FLAG_GHOST: flag that specifies a "non-existing"
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* picture, without any viable GstVideoCodecFrame associated to it.
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* i.e. a dummy picture with some valid contents
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* @GST_VAAPI_PICTURE_FLAG_SHORT_TERM_REFERENCE: flag that specifies
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* "used for short-term reference"
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* @GST_VAAPI_PICTURE_FLAG_LONG_TERM_REFERENCE: flag that specifies
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@ -174,6 +177,7 @@ enum {
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GST_VAAPI_PICTURE_FLAG_ANCHOR = (GST_VAAPI_PICTURE_FLAG_LAST << 3),
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GST_VAAPI_PICTURE_FLAG_AU_START = (GST_VAAPI_PICTURE_FLAG_LAST << 4),
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GST_VAAPI_PICTURE_FLAG_AU_END = (GST_VAAPI_PICTURE_FLAG_LAST << 5),
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GST_VAAPI_PICTURE_FLAG_GHOST = (GST_VAAPI_PICTURE_FLAG_LAST << 6),
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GST_VAAPI_PICTURE_FLAG_SHORT_TERM_REFERENCE = (
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GST_VAAPI_PICTURE_FLAG_REFERENCE),
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@ -705,24 +709,25 @@ dpb_remove_index(GstVaapiDecoderH264 *decoder, guint index)
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static gboolean
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dpb_output(GstVaapiDecoderH264 *decoder, GstVaapiFrameStore *fs)
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{
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GstVaapiPictureH264 *picture;
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GstVaapiPictureH264 *picture = NULL;
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guint i;
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g_return_val_if_fail(fs != NULL, FALSE);
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if (!gst_vaapi_frame_store_is_complete(fs))
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return TRUE;
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picture = fs->buffers[0];
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g_return_val_if_fail(picture != NULL, FALSE);
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picture->output_needed = FALSE;
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if (fs->num_buffers > 1) {
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picture = fs->buffers[1];
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g_return_val_if_fail(picture != NULL, FALSE);
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picture->output_needed = FALSE;
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for (i = 0; i < fs->num_buffers; i++) {
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GstVaapiPictureH264 * const pic = fs->buffers[i];
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g_return_val_if_fail(pic != NULL, FALSE);
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pic->output_needed = FALSE;
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if (!GST_VAAPI_PICTURE_FLAG_IS_SET(pic, GST_VAAPI_PICTURE_FLAG_GHOST))
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picture = pic;
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}
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fs->output_needed = 0;
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if (!picture)
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return TRUE;
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return gst_vaapi_picture_output(GST_VAAPI_PICTURE_CAST(picture));
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}
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@ -753,6 +758,41 @@ dpb_find_picture(GstVaapiDecoderH264 *decoder, GstVaapiPictureH264 *picture)
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return -1;
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}
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/* Finds the picture with the nearest previous POC and same structure */
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static gint
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dpb_find_nearest_prev_poc(GstVaapiDecoderH264 *decoder,
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GstVaapiPictureH264 *picture, guint picture_structure,
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GstVaapiPictureH264 **found_picture_ptr)
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{
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GstVaapiDecoderH264Private * const priv = &decoder->priv;
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GstVaapiPictureH264 *found_picture = NULL;
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guint i, j, found_index;
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g_return_val_if_fail(picture != NULL, -1);
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if (!picture_structure)
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picture_structure = picture->base.structure;
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for (i = 0; i < priv->dpb_count; i++) {
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GstVaapiFrameStore * const fs = priv->dpb[i];
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if (picture->base.view_id != fs->view_id)
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continue;
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for (j = 0; j < fs->num_buffers; j++) {
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GstVaapiPictureH264 * const pic = fs->buffers[j];
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if (pic->base.structure != picture_structure)
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continue;
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if (pic->base.poc >= picture->base.poc)
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continue;
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if (!found_picture || found_picture->base.poc < pic->base.poc)
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found_picture = pic, found_index = i;
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}
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}
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if (found_picture_ptr)
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*found_picture_ptr = found_picture;
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return found_picture ? found_index : -1;
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}
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/* Finds the picture with the lowest POC that needs to be output */
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static gint
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dpb_find_lowest_poc(GstVaapiDecoderH264 *decoder, GstVaapiPictureH264 *picture,
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@ -2899,6 +2939,63 @@ init_picture_refs(
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}
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}
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static GstVaapiPictureH264 *
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fill_picture_other_field_gap(GstVaapiDecoderH264 *decoder,
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GstVaapiPictureH264 *f0)
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{
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GstVaapiPictureH264 *prev_picture, *f1;
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gint prev_picture_index;
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guint picture_structure;
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picture_structure = f0->base.structure;
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switch (picture_structure) {
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case GST_VAAPI_PICTURE_STRUCTURE_TOP_FIELD:
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picture_structure = GST_VAAPI_PICTURE_STRUCTURE_BOTTOM_FIELD;
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break;
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case GST_VAAPI_PICTURE_STRUCTURE_BOTTOM_FIELD:
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picture_structure = GST_VAAPI_PICTURE_STRUCTURE_TOP_FIELD;
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break;
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default:
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g_assert(0 && "unexpected picture structure");
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return NULL;
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}
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GST_VAAPI_PICTURE_FLAG_SET(f0, GST_VAAPI_PICTURE_FLAG_ONEFIELD);
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prev_picture_index = dpb_find_nearest_prev_poc(decoder, f0,
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picture_structure, &prev_picture);
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if (prev_picture_index < 0)
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return NULL;
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f1 = gst_vaapi_picture_h264_new_field(f0);
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if (!f1)
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goto error_allocate_field;
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gst_vaapi_surface_proxy_replace(&f1->base.proxy, prev_picture->base.proxy);
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f1->base.surface = GST_VAAPI_SURFACE_PROXY_SURFACE(f1->base.proxy);
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f1->base.surface_id = GST_VAAPI_SURFACE_PROXY_SURFACE_ID(f1->base.proxy);
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f1->base.poc++;
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f1->structure = f1->base.structure;
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/* XXX: clone other H.264 picture specific flags */
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GST_VAAPI_PICTURE_FLAG_SET(f1,
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(GST_VAAPI_PICTURE_FLAG_SKIPPED |
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GST_VAAPI_PICTURE_FLAG_GHOST));
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if (!dpb_add(decoder, f1))
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goto error_append_field;
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gst_vaapi_picture_unref(f1);
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return f1;
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/* ERRORS */
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error_allocate_field:
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GST_ERROR("failed to allocate missing field for previous frame store");
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return NULL;
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error_append_field:
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GST_ERROR("failed to add missing field into previous frame store");
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gst_vaapi_picture_unref(f1);
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return NULL;
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}
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static gboolean
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init_picture(
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GstVaapiDecoderH264 *decoder,
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@ -3519,24 +3616,60 @@ is_new_access_unit(GstVaapiParserInfoH264 *pi, GstVaapiParserInfoH264 *prev_pi)
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return pi->voc < prev_pi->voc;
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}
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/* Determines whether the supplied picture has the same field parity
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than a picture specified through the other slice header */
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static inline gboolean
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same_field_parity(GstVaapiPictureH264 *field, GstH264SliceHdr *slice_hdr)
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{
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g_return_val_if_fail(GST_VAAPI_PICTURE_IS_INTERLACED(field), FALSE);
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return ((field->base.structure == GST_VAAPI_PICTURE_STRUCTURE_BOTTOM_FIELD) ^
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slice_hdr->bottom_field_flag) == 0;
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}
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/* Finds the first field picture corresponding to the supplied picture */
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static GstVaapiPictureH264 *
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find_first_field(GstVaapiDecoderH264 *decoder, GstVaapiParserInfoH264 *pi)
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find_first_field(GstVaapiDecoderH264 *decoder, GstVaapiParserInfoH264 *pi,
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gboolean fill_gaps)
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{
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GstVaapiDecoderH264Private * const priv = &decoder->priv;
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GstH264SliceHdr * const slice_hdr = &pi->data.slice_hdr;
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GstVaapiFrameStore *fs;
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if (!slice_hdr->field_pic_flag)
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return NULL;
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GstVaapiPictureH264 *f0, *f1;
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fs = priv->prev_frames[pi->voc];
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if (!fs || gst_vaapi_frame_store_has_frame(fs))
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if (!fs)
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return NULL;
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if (fs->buffers[0]->frame_num == slice_hdr->frame_num)
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return fs->buffers[0];
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return NULL;
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f0 = fs->buffers[0];
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if (!slice_hdr->field_pic_flag) {
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if (fill_gaps && !gst_vaapi_frame_store_has_frame(fs))
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fill_picture_other_field_gap(decoder, f0);
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return NULL;
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}
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/* At this point, the current frame is known to be interlaced */
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if (gst_vaapi_frame_store_has_frame(fs)) {
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f1 = NULL;
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return f1;
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}
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/* At this point, the previous frame is interlaced and contains a
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single field */
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if (f0->frame_num == slice_hdr->frame_num) {
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f1 = f0;
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if (fill_gaps && same_field_parity(f0, slice_hdr)) {
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fill_picture_other_field_gap(decoder, f0);
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f1 = NULL;
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}
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return f1;
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}
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f1 = NULL;
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if (fill_gaps) {
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fill_picture_other_field_gap(decoder, f0);
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}
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return f1;
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}
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static GstVaapiDecoderStatus
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@ -3566,7 +3699,7 @@ decode_picture(GstVaapiDecoderH264 *decoder, GstVaapiDecoderUnit *unit)
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priv->decoder_state = 0;
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first_field = find_first_field(decoder, pi);
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first_field = find_first_field(decoder, pi, TRUE);
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if (first_field) {
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/* Re-use current picture where the first field was decoded */
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picture = gst_vaapi_picture_h264_new_field(first_field);
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