From: Aman Gupta <a...@tmm1.net> This fixes decoding of H264 video samples with SPS and PPS changes.
See for example https://s3.amazonaws.com/tmm1/videotoolbox/spschange.ts, which previously stalled the decoder and failed to produce any new frames after the SPS change. 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/videotoolbox.c | 43 +++++++++++++++++++++++++++++++++++++++++-- libavcodec/vt_internal.h | 6 ++++++ 2 files changed, 47 insertions(+), 2 deletions(-) diff --git a/libavcodec/videotoolbox.c b/libavcodec/videotoolbox.c index 9db2e1116b..2496e4969c 100644 --- a/libavcodec/videotoolbox.c +++ b/libavcodec/videotoolbox.c @@ -42,6 +42,9 @@ enum { kCMVideoCodecType_HEVC = 'hvc1' }; #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; @@ -307,6 +310,27 @@ int ff_videotoolbox_h264_start_frame(AVCodecContext *avctx, return 0; } +static int videotoolbox_h264_decode_params(AVCodecContext *avctx, + int type, + const uint8_t *buffer, + uint32_t size) +{ + VTContext *vtctx = avctx->internal->hwaccel_priv_data; + + if (type == 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); + vtctx->reconfig_needed = true; + vtctx->sps_len = size; + } + } + + // 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) @@ -339,6 +363,7 @@ 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); } @@ -591,17 +616,30 @@ 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); if (status != noErr) { + if (status == kVTVideoDecoderMalfunctionErr || status == kVTInvalidSessionErr) + vtctx->reconfig_needed = true; av_log(avctx, AV_LOG_ERROR, "Failed to decode frame (%s, %d)\n", videotoolbox_error_string(status), (int)status); return AVERROR_UNKNOWN; } - if (!vtctx->frame) + if (!vtctx->frame) { + vtctx->reconfig_needed = true; return AVERROR_UNKNOWN; + } return videotoolbox_buffer_create(avctx, frame); } @@ -1003,6 +1041,7 @@ 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, diff --git a/libavcodec/vt_internal.h b/libavcodec/vt_internal.h index 607dd7a6d0..fc27dad9f9 100644 --- a/libavcodec/vt_internal.h +++ b/libavcodec/vt_internal.h @@ -38,6 +38,12 @@ 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); -- 2.14.2 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
