[FFmpeg-devel] [PATCH 13/14] mmal: add option copy_frame to support retrieving sw frames w/o copy

[Wang Bin]

2017-12-16 2:50 GMT+08:00 wm4 <nfxjfg at googlemail.com>:
> On Fri, 15 Dec 2017 15:05:50 +0800
> wbsecg1 at gmail.com wrote:
>
>> From: wang-bin <wbsecg1 at gmail.com>
>>
>> mmal buffer->data is already in host memory. AFAIK decoders implemented in omx must
>> be configured to output frames to either memory or something directly used by renderer,
>> for example mediacodec surface, mmal buffer and omxil eglimage.
>> test result: big buck bunny 1080p fps increases from about 100 to 110 if copy_frame is
>> turned off
>> ---
>>  libavcodec/mmaldec.c | 31 +++++++++++++++++++++++--------
>>  1 file changed, 23 insertions(+), 8 deletions(-)
>>
>> diff --git a/libavcodec/mmaldec.c b/libavcodec/mmaldec.c
>> index c1cfb09283..9cd6c6558f 100644
>> --- a/libavcodec/mmaldec.c
>> +++ b/libavcodec/mmaldec.c
>> @@ -69,6 +69,7 @@ typedef struct MMALDecodeContext {
>>      AVClass *av_class;
>>      int extra_buffers;
>>      int extra_decoder_buffers;
>> +    int copy_frame;
>>
>>      MMAL_COMPONENT_T *decoder;
>>      MMAL_QUEUE_T *queue_decoded_frames;
>> @@ -139,7 +140,6 @@ static int ffmmal_set_ref(AVFrame *frame, FFPoolRef *pool,
>>      atomic_fetch_add_explicit(&ref->pool->refcount, 1, memory_order_relaxed);
>>      mmal_buffer_header_acquire(buffer);
>>
>> -    frame->format = AV_PIX_FMT_MMAL;
>>      frame->data[3] = (uint8_t *)ref->buffer;
>>      return 0;
>>  }
>> @@ -650,20 +650,34 @@ static int ffmal_copy_frame(AVCodecContext *avctx,  AVFrame *frame,
>>
>>          if ((ret = ffmmal_set_ref(frame, ctx->pool_out, buffer)) < 0)
>>              goto done;
>> +        frame->format = AV_PIX_FMT_MMAL;
>>      } else {
>>          int w = FFALIGN(avctx->width, 32);
>>          int h = FFALIGN(avctx->height, 16);
>>          uint8_t *src[4];
>>          int linesize[4];
>>
>> -        if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
>> -            goto done;
>> +        if (ctx->copy_frame) {
>> +            if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
>> +                goto done;
>>
>> -        av_image_fill_arrays(src, linesize,
>> -                             buffer->data + buffer->type->video.offset[0],
>> -                             avctx->pix_fmt, w, h, 1);
>> -        av_image_copy(frame->data, frame->linesize, src, linesize,
>> -                      avctx->pix_fmt, avctx->width, avctx->height);
>> +            av_image_fill_arrays(src, linesize,
>> +                                buffer->data + buffer->type->video.offset[0],
>> +                                avctx->pix_fmt, w, h, 1);
>> +            av_image_copy(frame->data, frame->linesize, src, linesize,
>> +                        avctx->pix_fmt, avctx->width, avctx->height);
>> +        } else {
>> +            if ((ret = ff_decode_frame_props(avctx, frame)) < 0)
>> +                goto done;
>> +            /* buffer->type->video.offset/pitch[i]; is always 0 */
>> +            av_image_fill_arrays(src, linesize,
>> +                                buffer->data + buffer->type->video.offset[0],
>> +                                avctx->pix_fmt, w, h, 1);
>> +            if ((ret = ffmmal_set_ref(frame, ctx->pool_out, buffer)) < 0)
>> +                goto done;
>> +            memcpy(frame->data, src, sizeof(src));
>> +            memcpy(frame->linesize, linesize, sizeof(linesize));
>> +        }
>>      }
>>
>>      frame->pts = buffer->pts == MMAL_TIME_UNKNOWN ? AV_NOPTS_VALUE : buffer->pts;
>> @@ -842,6 +856,7 @@ AVHWAccel ff_wmv3_mmal_hwaccel = {
>>  static const AVOption options[]={
>>      {"extra_buffers", "extra buffers", offsetof(MMALDecodeContext, extra_buffers), AV_OPT_TYPE_INT, {.i64 = 10}, 0, 256, 0},
>>      {"extra_decoder_buffers", "extra MMAL internal buffered frames", offsetof(MMALDecodeContext, extra_decoder_buffers), AV_OPT_TYPE_INT, {.i64 = 10}, 0, 256, 0},
>> +    {"copy_frame", "copy deocded data to avframe", offsetof(MMALDecodeContext, copy_frame), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 256, 0},
>>      {NULL}
>>  };
>>
>
> Didn't check too closely what exactly the patch does, but adding an
> option for it sounds very wrong. The user select in the get_format
> callback whether a GPU surface is output (MMAL pixfmt), or software.

Avoid copying data from mmal buffer->data to avframe data. Instead,
just fill strides and address of each plane in avframe, and add a
reference to mmal buffer.