This allows the application to fallback to another hwaccel, or more
likely, to software decoding.
---
libavcodec/avcodec.h | 4 ++++
libavcodec/utils.c | 64 ++++++++++++++++++++++++++++++++++++++--------------
2 files changed, 51 insertions(+), 17 deletions(-)
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 253e45a..9f7922f 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -1294,6 +1294,10 @@ typedef struct AVCodecContext {
* @param fmt is the list of formats which are supported by the codec,
* it is terminated by -1 as 0 is a valid format, the formats are ordered
by quality.
* The first is always the native one.
+ * @note The callback may be called again immediately if initialization for
+ * the selected (hardware-accelerated) pixel format failed.
+ * @warning Behavior is undefined if the callback returns a value not
+ * in the fmt list of formats.
* @return the chosen format
* - encoding: unused
* - decoding: Set by user, if not set the native format will be chosen.
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index c5fa50d..816a11e 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -902,45 +902,75 @@ static AVHWAccel *find_hwaccel(enum AVCodecID codec_id,
int ff_get_format(AVCodecContext *avctx, const enum AVPixelFormat *fmt)
{
const AVPixFmtDescriptor *desc;
- enum AVPixelFormat ret = avctx->get_format(avctx, fmt);
+ enum AVPixelFormat *choices;
+ enum AVPixelFormat ret;
+ unsigned n = 0;
- desc = av_pix_fmt_desc_get(ret);
- if (!desc)
+ while (fmt[n] != AV_PIX_FMT_NONE)
+ ++n;
+
+ choices = av_malloc_array(n + 1, sizeof(*choices));
+ if (choices == NULL)
return AV_PIX_FMT_NONE;
- if (avctx->hwaccel && avctx->hwaccel->uninit)
- avctx->hwaccel->uninit(avctx);
- av_freep(&avctx->internal->hwaccel_priv_data);
- avctx->hwaccel = NULL;
+ memcpy(choices, fmt, (n + 1) * sizeof(*choices));
- if (desc->flags & AV_PIX_FMT_FLAG_HWACCEL) {
+ for (;;)
+ {
AVHWAccel *hwaccel;
- int err;
+ int err = 0;
+
+ ret = avctx->get_format(avctx, choices);
+
+ desc = av_pix_fmt_desc_get(ret);
+ if (!desc) {
+ ret = AV_PIX_FMT_NONE;
+ break;
+ }
+
+ if (avctx->hwaccel && avctx->hwaccel->uninit)
+ avctx->hwaccel->uninit(avctx);
+ av_freep(&avctx->internal->hwaccel_priv_data);
+ avctx->hwaccel = NULL;
+
+ if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL))
+ break;
hwaccel = find_hwaccel(avctx->codec_id, ret);
if (!hwaccel) {
av_log(avctx, AV_LOG_ERROR,
"Could not find an AVHWAccel for the pixel format: %s",
desc->name);
- return AV_PIX_FMT_NONE;
+ err = AVERROR(ENOENT);
}
- if (hwaccel->priv_data_size) {
+ if (err == 0 && hwaccel->priv_data_size) {
avctx->internal->hwaccel_priv_data =
av_mallocz(hwaccel->priv_data_size);
if (!avctx->internal->hwaccel_priv_data)
- return AV_PIX_FMT_NONE;
+ err = AVERROR(ENOMEM);
}
- if (hwaccel->init) {
+ if (err == 0 && hwaccel->init) {
err = hwaccel->init(avctx);
- if (err < 0) {
+ if (err < 0)
av_freep(&avctx->internal->hwaccel_priv_data);
- return AV_PIX_FMT_NONE;
- }
}
- avctx->hwaccel = hwaccel;
+
+ if (err == 0) {
+ avctx->hwaccel = hwaccel;
+ break;
+ }
+
+ /* Remove failed hwaccel from choices */
+ for (n = 0; choices[n] != ret; n++)
+ av_assert0(choices[n] != AV_PIX_FMT_NONE);
+
+ do
+ choices[n] = choices[n + 1];
+ while (choices[n] != AV_PIX_FMT_NONE);
}
+ av_freep(&choices);
return ret;
}
--
1.8.1.5
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