On Mon, 25 Sep 2017 17:36:30 -0700 Aman Gupta <ffmpeg@tmm1.net> wrote:
From: Aman Gupta <aman@tmm1.net>
If the VideoToolbox session needs to be restarted, and videotoolbox_start() fails for some reason (for instance, if the video is interlaced and the decoder is running on iOS), avcodec will return AVERROR_EXTERNAL. This can be used by the API user to switch to another decoder. --- libavcodec/vda_vt_internal.h | 6 ++++++ libavcodec/videotoolbox.c | 45 +++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 50 insertions(+), 1 deletion(-)
diff --git a/libavcodec/vda_vt_internal.h b/libavcodec/vda_vt_internal.h index e55a813899..49c91791ee 100644 --- a/libavcodec/vda_vt_internal.h +++ b/libavcodec/vda_vt_internal.h @@ -47,6 +47,12 @@ typedef struct VTContext { // Non-NULL if the new hwaccel API is used. This is only a separate struct // to ease compatibility with the old API. struct AVVideotoolboxContext *vt_ctx; + + // Current H264 parameters (used to trigger decoder restart on SPS changes). + uint8_t *sps; + uint32_t sps_len; + unsigned int sps_capa; + bool reconfig_needed; } VTContext;
int ff_videotoolbox_alloc_frame(AVCodecContext *avctx, AVFrame *frame); diff --git a/libavcodec/videotoolbox.c b/libavcodec/videotoolbox.c index f56ab1f8c9..6c8477c2ce 100644 --- a/libavcodec/videotoolbox.c +++ b/libavcodec/videotoolbox.c @@ -41,6 +41,9 @@
#define VIDEOTOOLBOX_ESDS_EXTRADATA_PADDING 12
+static void videotoolbox_stop(AVCodecContext *avctx); +static int videotoolbox_start(AVCodecContext *avctx); + static void videotoolbox_buffer_release(void *opaque, uint8_t *data) { CVPixelBufferRef cv_buffer = (CVImageBufferRef)data; @@ -148,6 +151,33 @@ int ff_videotoolbox_h264_start_frame(AVCodecContext *avctx, return 0; }
+static int videotoolbox_h264_decode_params(AVCodecContext *avctx, + const uint8_t *buffer, + uint32_t size) +{ + VTContext *vtctx = avctx->internal->hwaccel_priv_data; + H264Context *h = avctx->priv_data; + + if (h->is_avc == 1) + return 0;
Should that matter?
+ switch (buffer[0] & 0x1f) { + case H264_NAL_SPS: + if (!vtctx->sps || vtctx->sps_len != size || memcmp(buffer, vtctx->sps, size) != 0) { + vtctx->sps = av_fast_realloc(vtctx->sps, &vtctx->sps_capa, size); + if (vtctx->sps) + memcpy(vtctx->sps, buffer, size); + if (vtctx->sps_len) + vtctx->reconfig_needed = true; + vtctx->sps_len = size; + } + break; + }
To be honest, I think just rebuilding the avcc and testing for a change would be simpler. Unless there's a good reason not to reinit when only the PPS changes. Might also make sense to pass the NAL type as parameter to the AVHWAccel function? Otherwise I'm fine with it.
+ // pass-through new PPS to the decoder + return ff_videotoolbox_h264_decode_slice(avctx, buffer, size); +} + int ff_videotoolbox_h264_decode_slice(AVCodecContext *avctx, const uint8_t *buffer, uint32_t size) @@ -180,6 +210,7 @@ int ff_videotoolbox_uninit(AVCodecContext *avctx) VTContext *vtctx = avctx->internal->hwaccel_priv_data; if (vtctx) { av_freep(&vtctx->bitstream); + av_freep(&vtctx->sps); if (vtctx->frame) CVPixelBufferRelease(vtctx->frame); } @@ -419,7 +450,16 @@ static int videotoolbox_common_end_frame(AVCodecContext *avctx, AVFrame *frame) AVVideotoolboxContext *videotoolbox = videotoolbox_get_context(avctx); VTContext *vtctx = avctx->internal->hwaccel_priv_data;
- if (!videotoolbox->session || !vtctx->bitstream) + if (vtctx->reconfig_needed == true) { + vtctx->reconfig_needed = false; + av_log(avctx, AV_LOG_VERBOSE, "VideoToolbox decoder needs reconfig, restarting..\n"); + videotoolbox_stop(avctx); + if (videotoolbox_start(avctx) != 0) { + return AVERROR_EXTERNAL; + } + } + + if (!videotoolbox->session || !vtctx->bitstream || !vtctx->bitstream_size) return AVERROR_INVALIDDATA;
status = videotoolbox_session_decode_frame(avctx); @@ -432,9 +472,11 @@ static int videotoolbox_common_end_frame(AVCodecContext *avctx, AVFrame *frame) break; case kVTVideoDecoderMalfunctionErr: error = "decoder malfunction"; + vtctx->reconfig_needed = true; break; case kVTInvalidSessionErr: error = "invalid session"; + vtctx->reconfig_needed = true; break; default: error = "unknown"; @@ -824,6 +866,7 @@ AVHWAccel ff_h264_videotoolbox_hwaccel = { .alloc_frame = ff_videotoolbox_alloc_frame, .start_frame = ff_videotoolbox_h264_start_frame, .decode_slice = ff_videotoolbox_h264_decode_slice, + .decode_params = videotoolbox_h264_decode_params, .end_frame = videotoolbox_h264_end_frame, .init = videotoolbox_common_init, .uninit = videotoolbox_uninit,