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Code Issues Releases Activity

vf_hwmap: Add reverse mapping for hardware frames

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This is something of a hack.  It allocates a new hwframe context for
the target format, then maps it back to the source link and overwrites
the input link hw_frames_ctx so that the previous filter will receive
the frames we want from ff_get_video_buffer().  It may fail if
the previous filter imposes any additional constraints on the frames
it wants to use as output.
This commit is contained in:
Mark Thompson 2017-03-04 23:57:42 +00:00
parent 38cb05f1c8
commit 81a4cb8e58
1 changed files with 61 additions and 7 deletions
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68
libavfilter/vf_hwmap.c
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@ -34,7 +34,7 @@ typedef struct HWMapContext {
int mode;
char *derive_device_type;
int map_backwards;
int reverse;
} HWMapContext;
static int hwmap_query_formats(AVFilterContext *avctx)
@ -92,7 +92,8 @@ static int hwmap_config_output(AVFilterLink *outlink)
}
if (inlink->format == hwfc->format &&
(desc->flags & AV_PIX_FMT_FLAG_HWACCEL)) {
(desc->flags & AV_PIX_FMT_FLAG_HWACCEL) &&
!ctx->reverse) {
// Map between two hardware formats (including the case of
// undoing an existing mapping).
@ -113,6 +114,56 @@ static int hwmap_config_output(AVFilterLink *outlink)
goto fail;
}
} else if (inlink->format == hwfc->format &&
(desc->flags & AV_PIX_FMT_FLAG_HWACCEL) &&
ctx->reverse) {
// Map between two hardware formats, but do it in reverse.
// Make a new hwframe context for the target type, and then
// overwrite the input hwframe context with a derived context
// mapped from that back to the source type.
AVBufferRef *source;
AVHWFramesContext *frames;
ctx->hwframes_ref = av_hwframe_ctx_alloc(device);
if (!ctx->hwframes_ref) {
err = AVERROR(ENOMEM);
goto fail;
}
frames = (AVHWFramesContext*)ctx->hwframes_ref->data;
frames->format = outlink->format;
frames->sw_format = hwfc->sw_format;
frames->width = hwfc->width;
frames->height = hwfc->height;
frames->initial_pool_size = 64;
err = av_hwframe_ctx_init(ctx->hwframes_ref);
if (err < 0) {
av_log(avctx, AV_LOG_ERROR, "Failed to initialise "
"target frames context: %d.\n", err);
goto fail;
}
err = av_hwframe_ctx_create_derived(&source,
inlink->format,
hwfc->device_ref,
ctx->hwframes_ref,
ctx->mode);
if (err < 0) {
av_log(avctx, AV_LOG_ERROR, "Failed to create "
"derived source frames context: %d.\n", err);
goto fail;
}
// Here is the naughty bit. This overwriting changes what
// ff_get_video_buffer() in the previous filter returns -
// it will now give a frame allocated here mapped back to
// the format it expects. If there were any additional
// constraints on the output frames there then this may
// break nastily.
av_buffer_unref(&inlink->hw_frames_ctx);
inlink->hw_frames_ctx = source;
} else if ((outlink->format == hwfc->format &&
inlink->format == hwfc->sw_format) ||
inlink->format == hwfc->format) {
@ -144,13 +195,13 @@ static int hwmap_config_output(AVFilterLink *outlink)
if (!device) {
av_log(avctx, AV_LOG_ERROR, "A device reference is "
"required to create new frames with backwards "
"required to create new frames with reverse "
"mapping.\n");
err = AVERROR(EINVAL);
goto fail;
}
ctx->map_backwards = 1;
ctx->reverse = 1;
ctx->hwframes_ref = av_hwframe_ctx_alloc(device);
if (!ctx->hwframes_ref) {
@ -167,7 +218,7 @@ static int hwmap_config_output(AVFilterLink *outlink)
err = av_hwframe_ctx_init(ctx->hwframes_ref);
if (err < 0) {
av_log(avctx, AV_LOG_ERROR, "Failed to create frame "
"context for backward mapping: %d.\n", err);
"context for reverse mapping: %d.\n", err);
goto fail;
}
@ -199,7 +250,7 @@ static AVFrame *hwmap_get_buffer(AVFilterLink *inlink, int w, int h)
AVFilterLink *outlink = avctx->outputs[0];
HWMapContext *ctx = avctx->priv;
if (ctx->map_backwards) {
if (ctx->reverse && !inlink->hw_frames_ctx) {
AVFrame *src, *dst;
int err;
@ -257,7 +308,7 @@ static int hwmap_filter_frame(AVFilterLink *link, AVFrame *input)
goto fail;
}
if (ctx->map_backwards && !input->hw_frames_ctx) {
if (ctx->reverse && !input->hw_frames_ctx) {
// If we mapped backwards from hardware to software, we need
// to attach the hardware frame context to the input frame to
// make the mapping visible to av_hwframe_map().
@ -323,6 +374,9 @@ static const AVOption hwmap_options[] = {
{ "derive_device", "Derive a new device of this type",
OFFSET(derive_device_type), AV_OPT_TYPE_STRING,
{ .str = NULL }, 0, 0, FLAGS },
{ "reverse", "Map in reverse (create and allocate in the sink)",
OFFSET(reverse), AV_OPT_TYPE_INT,
{ .i64 = 0 }, 0, 1, FLAGS },
{ NULL },
};