void CMMALRenderer::Process()
{
MMAL_BUFFER_HEADER_T *buffer;
while (buffer = mmal_queue_wait(m_release_queue), buffer && buffer != &m_quit_packet)
{
CMMALVideoBuffer *omvb = (CMMALVideoBuffer *)buffer->user_data;
omvb->Release();
}
m_sync.Set();
}
// Fetch a decoded buffer and place it into the frame parameter.
static int ffmmal_read_frame(AVCodecContext *avctx, AVFrame *frame, int *got_frame)
{
MMALDecodeContext *ctx = avctx->priv_data;
MMAL_BUFFER_HEADER_T *buffer = NULL;
MMAL_STATUS_T status = 0;
int ret = 0;
if (ctx->eos_received)
goto done;
while (1) {
// To ensure decoding in lockstep with a constant delay between fed packets
// and output frames, we always wait until an output buffer is available.
// Except during start we don't know after how many input packets the decoder
// is going to return the first buffer, and we can't distinguish decoder
// being busy from decoder waiting for input. So just poll at the start and
// keep feeding new data to the buffer.
// We are pretty sure the decoder will produce output if we sent more input
// frames than what a h264 decoder could logically delay. This avoids too
// excessive buffering.
// We also wait if we sent eos, but didn't receive it yet (think of decoding
// stream with a very low number of frames).
if (ctx->frames_output || ctx->packets_sent > MAX_DELAYED_FRAMES || ctx->eos_sent) {
buffer = mmal_queue_wait(ctx->queue_decoded_frames);
} else {
buffer = mmal_queue_get(ctx->queue_decoded_frames);
}
if (!buffer)
goto done;
ctx->eos_received |= !!(buffer->flags & MMAL_BUFFER_HEADER_FLAG_EOS);
if (ctx->eos_received)
goto done;
if (buffer->cmd == MMAL_EVENT_FORMAT_CHANGED) {
MMAL_COMPONENT_T *decoder = ctx->decoder;
MMAL_EVENT_FORMAT_CHANGED_T *ev = mmal_event_format_changed_get(buffer);
MMAL_BUFFER_HEADER_T *stale_buffer;
av_log(avctx, AV_LOG_INFO, "Changing output format.\n");
if ((status = mmal_port_disable(decoder->output[0])))
goto done;
while ((stale_buffer = mmal_queue_get(ctx->queue_decoded_frames)))
mmal_buffer_header_release(stale_buffer);
mmal_format_copy(decoder->output[0]->format, ev->format);
if ((ret = ffmal_update_format(avctx)) < 0)
goto done;
if ((status = mmal_port_enable(decoder->output[0], output_callback)))
goto done;
if ((ret = ffmmal_fill_output_port(avctx)) < 0)
goto done;
if ((ret = ffmmal_fill_input_port(avctx)) < 0)
goto done;
mmal_buffer_header_release(buffer);
continue;
} else if (buffer->cmd) {
char s[20];
av_get_codec_tag_string(s, sizeof(s), buffer->cmd);
av_log(avctx, AV_LOG_WARNING, "Unknown MMAL event %s on output port\n", s);
goto done;
} else if (buffer->length == 0) {
// Unused output buffer that got drained after format change.
mmal_buffer_header_release(buffer);
continue;
}
ctx->frames_output++;
if ((ret = ffmal_copy_frame(avctx, frame, buffer)) < 0)
goto done;
*got_frame = 1;
break;
}
done:
if (buffer)
mmal_buffer_header_release(buffer);
if (status && ret >= 0)
ret = AVERROR_UNKNOWN;
return ret;
}
